U.S. patent application number 17/083254 was filed with the patent office on 2022-05-05 for high-band signal generation.
The applicant listed for this patent is QUALCOMM Incorporated. Invention is credited to Venkatraman ATTI, Venkata Subrahmanyam Chandra Sekhar CHEBIYYAM.
Application Number | 20220139410 17/083254 |
Document ID | / |
Family ID | 1000006285011 |
Filed Date | 2022-05-05 |
United States Patent
Application |
20220139410 |
Kind Code |
A9 |
ATTI; Venkatraman ; et
al. |
May 5, 2022 |
HIGH-BAND SIGNAL GENERATION
Abstract
A device for signal processing includes a memory and a
processor. The memory is configured to store a parameter associated
with a bandwidth-extended audio stream. The processor is configured
to select a plurality of non-linear processing functions based at
least in part on a value of the parameter. The processor is also
configured to generate a high-band excitation signal based on the
plurality of non-linear processing functions.
Inventors: |
ATTI; Venkatraman; (San
Diego, CA) ; CHEBIYYAM; Venkata Subrahmanyam Chandra
Sekhar; (Seattle, WA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
QUALCOMM Incorporated |
San Diego |
CA |
US |
|
|
Prior
Publication: |
|
Document Identifier |
Publication Date |
|
US 20210065727 A1 |
March 4, 2021 |
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|
Family ID: |
1000006285011 |
Appl. No.: |
17/083254 |
Filed: |
October 28, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15164583 |
May 25, 2016 |
10847170 |
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17083254 |
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62241065 |
Oct 13, 2015 |
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62181702 |
Jun 18, 2015 |
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Current U.S.
Class: |
704/206 |
Current CPC
Class: |
G10L 19/087 20130101;
G10L 19/167 20130101; G10L 19/03 20130101; G10L 19/24 20130101;
G10L 21/0388 20130101; G10L 19/0204 20130101 |
International
Class: |
G10L 19/087 20060101
G10L019/087; G10L 19/24 20060101 G10L019/24; G10L 19/02 20060101
G10L019/02; G10L 19/03 20060101 G10L019/03; G10L 19/16 20060101
G10L019/16 |
Claims
1. A device for signal processing comprising: a receiver configured
to receive an encoded audio signal, wherein the encoded audio
signal comprises a parameter; a memory configured to store the
parameter associated with a bandwidth-extended audio stream; and a
processor configured to: select a plurality of non-linear
processing functions based at least in part on a value of the
parameter, wherein the plurality of non-linear processing functions
comprise a first non-linear processing function and a second
non-linear processing function, wherein the first non-linear
processing function is different from the second non-linear
processing function; generate a first excitation signal based on
the first non-linear processing function; generate a second
excitation signal based on the second non-linear processing
function; and generate a high-band excitation signal based on the
first excitation signal and the second excitation signal, wherein
the first excitation signal corresponds to a first high-band
frequency sub-range, and wherein the second excitation signal
corresponds to a second high-band frequency sub-range.
2. The device of claim 1, wherein the processor is further
configured to generate a resampled signal based on a low-band
excitation signal, wherein the high-band excitation signal is based
at least in part on the resampled signal.
3. The device of claim 1, wherein the processor is further
configured to: generate a first filtered signal by applying a
low-pass filter to the first excitation signal; and generate a
second filtered signal by applying a high-pass filter to the second
excitation signal, wherein the high-band excitation signal is
generated by combining the first filtered signal and the second
filtered signal.
4. The device of claim 1, wherein the processor is further
configured to: generate the first excitation signal based on
application of the first non-linear processing function of the
plurality of non-linear processing functions to a resampled signal,
and generate the second excitation signal based on application of
the second non-linear processing function of the plurality of
non-linear functions to the resampled signal, wherein the high-band
excitation signal is based on the first excitation signal and the
second excitation signal.
5. The device of claim 4, wherein the processor is further
configured to generate at least one additional excitation signal,
wherein the at least one additional excitation signal is generated
based on application of at least one additional function to the
resampled signal, wherein the high-band excitation signal is
generated further based on the at least one additional excitation
signal, and wherein the first excitation signal corresponds to a
first high-band frequency sub-range, the second excitation signal
corresponds to a second high-band frequency sub-range, and the at
least one additional excitation signal corresponds to at least one
additional high-band frequency sub-range.
6. The device of claim 4, wherein the first function includes a
square function, and wherein the second function includes an
absolute value function.
7. The device of claim 1, wherein the parameter includes a
non-linear configuration mode.
8. The device of claim 1, wherein the first non-linear processing
function corresponds to an absolute value function and the second
non-linear processing function corresponds to a square function,
and wherein the processor is configured to: select the absolute
value function in response to determining that the parameter has a
first value, and select a square function or the plurality of
non-linear processing functions in response to determining that the
parameter has a second value.
9. The device of claim 1, wherein the processor is configured to
select the plurality of non-linear processing functions in response
to determining that the parameter has a second value and that a
second parameter associated with the bandwidth-extended audio
stream has a particular value.
10. The device of claim 9, wherein the second parameter includes a
mix configuration mode.
11. The device of claim 1, further comprising: an antenna coupled
to the receiver.
12. The device of claim 11, further comprising a demodulator
coupled to the receiver, the demodulator configured to demodulate
the encoded audio signal.
13. The device of claim 12, further comprising a decoder coupled to
the processor, the decoder configured to decode the encoded audio
signal, wherein the encoded audio signal corresponds to the
bandwidth-extended audio stream, and wherein the processor is
coupled to the demodulator.
14. The device of claim 13, wherein the receiver, the demodulator,
the processor, and the decoder are integrated into a mobile
communication device.
15. The device of claim 13, wherein the receiver, the demodulator,
the processor, and the decoder are integrated into a base station,
the base station further comprising a transcoder that includes the
decoder.
16. The device of claim 1, wherein the processor and the memory are
integrated into a media playback device or a media broadcast
device.
17. A signal processing method comprising: receiving, at a device,
an encoded audio signal, wherein the encoded audio signal comprises
a parameter; selecting, at the device, a plurality of non-linear
processing functions based at least in part on a value of the
parameter, wherein the plurality of non-linear processing functions
comprise a first non-linear processing function and a second
non-linear processing function, wherein the first non-linear
processing function is different from the second non-linear
processing function; generating, at the device, a first excitation
signal based on the first non-linear processing function;
generating, at the device, a second excitation signal based on the
second non-linear processing function; and generating, at the
device, a high-band excitation signal based on the first excitation
signal and the second excitation signal, wherein the first
excitation signal corresponds to a first high-band frequency
sub-range, and wherein the second excitation signal corresponds to
a second high-band frequency sub-range.
18. The method of claim 17, wherein the device comprises a media
playback device or a media broadcast device.
19. The method of claim 17, wherein the device comprises a mobile
communication device.
20. The method of claim 17, wherein the device comprises a base
station.
21. A computer-readable storage device storing instructions that,
when executed by a processor, cause the processor to perform
operations comprising: selecting a plurality of non-linear
processing functions based at least in part on a value of a
parameter, wherein the plurality of non-linear processing functions
comprise a first non-linear processing function and a second
non-linear processing function, wherein the first non-linear
processing function is different from the second non-linear
processing function, wherein the parameter received from an encoder
in an encoded audio signal; generating a first excitation signal
based on the first non-linear processing function; generating a
second excitation signal based on the second non-linear processing
function; and generating a high-band excitation signal based on the
first excitation signal and the second excitation signal, wherein
the first excitation signal corresponds to a first high-band
frequency sub-range, and wherein the second excitation signal
corresponds to a second high-band frequency sub-range.
22. The computer-readable storage device of claim 21, wherein the
plurality of non-linear processing functions is selected in
response to determining that the parameter has a first particular
value and that a second parameter associated with the
bandwidth-extended audio stream has a second particular value.
23. An apparatus comprising: means for receiving an encoded audio
signal, wherein the encoded audio signal comprises a parameter;
means for storing the parameter associated with a
bandwidth-extended audio stream; means for generating a first
excitation signal based on the first non-linear processing
function, wherein the first non-linear processing function selected
based at least in part on a value of the parameter; means for
generating a second excitation signal based on the second
non-linear processing function, wherein the second non-linear
processing function selected based at least in part on a value of
the parameter, wherein the first non-linear processing function is
different from the second non-linear processing function; and means
for generating a high-band excitation signal based on the first
excitation signal and the second excitation signal, wherein the
first excitation signal corresponds to a first high-band frequency
sub-range, and wherein the second excitation signal corresponds to
a second high-band frequency sub-range.
Description
I. CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. Non-Provisional
application Ser. No. 15/164,583, filed May 25, 2016, and entitled
"HIGH-BAND SIGNAL GENERATION" (Atty. Dkt. No. 154081U1); which
claims the benefit of and priority to U.S. Provisional Application
No. 62/181,702, filed Jun. 18, 2015 and entitled "HIGH-BAND SIGNAL
GENERATION" (Atty. Dkt. No. 154081P1), and U.S. Provisional Patent
Application No. 62/241,065, filed Oct. 13, 2015 and entitled
"HIGH-BAND SIGNAL GENERATION" (Atty. Dkt. No. 154081P2); the
contents of each of the applications are expressly incorporated
herein by reference in their entirety.
II. FIELD
[0002] The present disclosure is generally related to high-band
signal generation.
III. DESCRIPTION OF RELATED ART
[0003] Advances in technology have resulted in smaller and more
powerful computing devices. For example, there currently exist a
variety of portable personal computing devices, including wireless
telephones such as mobile and smart phones, tablets and laptop
computers that are small, lightweight, and easily carried by users.
These devices can communicate voice and data packets over wireless
networks. Further, many such devices incorporate additional
functionality such as a digital still camera, a digital video
camera, a digital recorder, and an audio file player. Also, such
devices can process executable instructions, including software
applications, such as a web browser application, that can be used
to access the Internet. As such, these devices can include
significant computing capabilities.
[0004] Transmission of audio, such as voice, by digital techniques
is widespread. If speech is transmitted by sampling and digitizing,
a data rate on the order of sixty-four kilobits per second (kbps)
may be used to achieve a speech quality of an analog telephone.
Compression techniques may be used to reduce the amount of
information that is sent over a channel while maintaining a
perceived quality of reconstructed speech. Through the use of
speech analysis, followed by coding, transmission, and re-synthesis
at a receiver, a significant reduction in the data rate may be
achieved.
[0005] Speech coders may be implemented as time-domain coders,
which attempt to capture the time-domain speech waveform by
employing high time-resolution processing to encode small segments
of speech (e.g., 5 millisecond (ms) sub-frames) at a time. For each
sub-frame, a high-precision representative from a codebook space is
found by means of a search algorithm.
[0006] One time-domain speech coder is the Code Excited Linear
Predictive (CELP) coder. In a CELP coder, the short-term
correlations, or redundancies, in the speech signal are removed by
a linear prediction (LP) analysis, which finds the coefficients of
a short-term formant filter. Applying the short-term prediction
filter to the incoming speech frame generates an LP residue signal,
which is further modeled and quantized with long-term prediction
filter parameters and a subsequent stochastic codebook. Thus, CELP
coding divides the task of encoding the time-domain speech waveform
into the separate tasks of encoding the LP short-term filter
coefficients and encoding the LP residue. Time-domain coding can be
performed at a fixed rate (i.e., using the same number of bits, No,
for each frame) or at a variable rate (in which different bit rates
are used for different types of frame contents). Variable-rate
coders attempt to use the amount of bits needed to encode the
parameters to a level adequate to obtain a target quality.
[0007] Wideband coding techniques involve encoding and transmitting
a lower frequency portion of a signal (e.g., 50 Hertz (Hz) to 7
kiloHertz (kHz), also called the "low-band"). In order to improve
coding efficiency, the higher frequency portion of the signal
(e.g., 7 kHz to 16 kHz, also called the "high-band") may not be
fully encoded and transmitted. Properties of the low-band signal
may be used to generate the high-band signal. For example, a
high-band excitation signal may be generated based on a low-band
residual using a non-linear model.
IV. SUMMARY
[0008] In a particular aspect, a device for signal processing
includes a memory and a processor. The memory is configured to
store a parameter associated with a bandwidth-extended audio
stream. The processor is configured to select a plurality of
non-linear processing functions based at least in part on a value
of the parameter. The processor is also configured to generate a
high-band excitation signal based on the plurality of non-linear
processing functions.
[0009] In another particular aspect, a signal processing method
includes selecting, at a device, a plurality of non-linear
processing functions based at least in part on a value of a
parameter. The parameter is associated with a bandwidth-extended
audio stream. The method also includes generating, at the device, a
high-band excitation signal based on the plurality of non-linear
processing functions.
[0010] In another particular aspect, a computer-readable storage
device stores instructions that, when executed by a processor,
cause the processor to perform operations including selecting a
plurality of non-linear processing functions based at least in part
on a value of a parameter. The parameter is associated with a
bandwidth-extended audio stream. The operations also include
generating a high-band excitation signal based on the plurality of
non-linear processing functions.
[0011] In another particular aspect, a device for signal processing
includes a receiver and a high-band excitation signal generator.
The receiver is configured to receive a parameter associated with a
bandwidth-extended audio stream. The high-band excitation signal
generator is configured to determine a value of the parameter. The
high-band excitation signal generator is also configured to select,
based on the value of the parameter, one of target gain information
associated with the bandwidth-extended audio stream or filter
information associated with the bandwidth-extended audio stream.
The high-band excitation signal generator is further configured to
generate a high-band excitation signal based on the one of the
target gain information or the filter information.
[0012] In another particular aspect, a signal processing method
includes receiving, at a device, a parameter associated with a
bandwidth-extended audio stream. The method also includes
determining, at the device, a value of the parameter. The method
further includes selecting, based on the value of the parameter,
one of target gain information associated with the
bandwidth-extended audio stream or filter information associated
with the bandwidth-extended audio stream. The method also includes
generating, at the device, a high-band excitation signal based on
the one of the target gain information or the filter
information.
[0013] In another particular aspect, a computer-readable storage
device stores instructions that, when executed by a processor,
cause the processor to perform operations including receiving a
parameter associated with a bandwidth-extended audio stream. The
operations also include determining a value of the parameter. The
operations further include selecting, based on the value of the
parameter, one of target gain information associated with the
bandwidth-extended audio stream or filter information associated
with the bandwidth-extended audio stream. The operations also
include generating a high-band excitation signal based on the one
of the target gain information or the filter information.
[0014] In another particular aspect, a device includes an encoder
and a transmitter. The encoder is configured to receive an audio
signal. The encoder is also configured to generate a signal
modeling parameter based on a harmonicity indicator, a peakiness
indicator, or both. The signal modeling parameter is associated
with a high-band portion of the audio signal. The transmitter is
configured to transmit the signal modeling parameter in conjunction
with a bandwidth-extended audio stream corresponding to the audio
signal.
[0015] In another particular aspect, a device includes an encoder
and a transmitter. The encoder is configured to receive an audio
signal. The encoder is also configured to generate a high-band
excitation signal based on a high-band portion of the audio signal.
The encoder is further configured to generate a modeled high-band
excitation signal based on a low-band portion of the audio signal.
The encoder is also configured to select a filter based on a
comparison of the modeled high-band excitation signal and the
high-band excitation signal. The transmitter is configured to
transmit filter information corresponding to the filter in
conjunction with a bandwidth-extended audio stream corresponding to
the audio signal.
[0016] In another particular aspect, a device includes an encoder
and a transmitter. The encoder is configured to receive an audio
signal. The encoder is also configured to generate a high-band
excitation signal based on a high-band portion of the audio signal.
The encoder is further configured to generate a modeled high-band
excitation signal based on a low-band portion of the audio signal.
The encoder is also configured to generate filter coefficients
based on a comparison of the modeled high-band excitation signal
and the high-band excitation signal. The encoder is further
configured to generate filter information by quantizing the filter
coefficients. The transmitter is configured to transmit the filter
information in conjunction with a bandwidth-extended audio stream
corresponding to the audio signal.
[0017] In another particular aspect, a method includes receiving an
audio signal at a first device. The method also includes
generating, at the first device, a signal modeling parameter based
on a harmonicity indicator, a peakiness indicator, or both. The
signal modeling parameter is associated with a high-band portion of
the audio signal. The method further includes sending, from the
first device to a second device, the signal modeling parameter in
conjunction with a bandwidth-extended audio stream corresponding to
the audio signal.
[0018] In another particular aspect, a method includes receiving an
audio signal at a first device. The method also includes
generating, at the first device, a high-band excitation signal
based on a high-band portion of the audio signal. The method
further includes generating, at the first device, a modeled
high-band excitation signal based on a low-band portion of the
audio signal. The method also includes selecting, at the first
device, a filter based on a comparison of the modeled high-band
excitation signal and the high-band excitation signal. The method
further includes sending, from the first device to a second device,
filter information corresponding to the filter in conjunction with
a bandwidth-extended audio stream corresponding to the audio
signal.
[0019] In another particular aspect, a method includes receiving an
audio signal at a first device. The method also includes
generating, at the first device, a high-band excitation signal
based on a high-band portion of the audio signal. The method
further includes generating, at the first device, a modeled
high-band excitation signal based on a low-band portion of the
audio signal. The method also includes generating, at the first
device, filter coefficients based on a comparison of the modeled
high-band excitation signal and the high-band excitation signal.
The method further includes generating, at the first device, filter
information by quantizing the filter coefficients. The method also
includes sending, from the first device to a second device, the
filter information in conjunction with a bandwidth-extended audio
stream corresponding to the audio signal.
[0020] In another particular aspect, a computer-readable storage
device stores instructions that, when executed by a processor,
cause the processor to perform operations including generating a
signal modeling parameter based on a harmonicity indicator, a
peakiness indicator, or both. The signal modeling parameter is
associated with a high-band portion of the audio signal. The
operations also include causing the signal modeling parameter to be
sent in conjunction with a bandwidth-extended audio stream
corresponding to the audio signal.
[0021] In another particular aspect, a computer-readable storage
device stores instructions that, when executed by a processor,
cause the processor to perform operations including generating a
high-band excitation signal based on a high-band portion of an
audio signal. The operations further include generating a modeled
high-band excitation signal based on a low-band portion of the
audio signal. The operations also include selecting a filter based
on a comparison of the modeled high-band excitation signal and the
high-band excitation signal. The operations further include causing
filter information corresponding to the filter to be sent in
conjunction with a bandwidth-extended audio stream corresponding to
the audio signal.
[0022] In another particular aspect, a computer-readable storage
device stores instructions that, when executed by a processor,
cause the processor to perform operations including generating a
high-band excitation signal based on a high-band portion of an
audio signal. The operations further include generating a modeled
high-band excitation signal based on a low-band portion of the
audio signal. The operations also include generating filter
coefficients based on a comparison of the modeled high-band
excitation signal and the high-band excitation signal. The
operations further include generating filter information by
quantizing the filter coefficients. The operations also include
causing the filter information to be sent in conjunction with a
bandwidth-extended audio stream corresponding to the audio
signal.
[0023] In another particular aspect, a device includes a resampler
and a harmonic extension module. The resampler is configured to
generate a resampled signal based on a low-band excitation signal.
The harmonic extension module is configured to generate at least a
first excitation signal corresponding to a first high-band
frequency sub-range and a second excitation signal corresponding to
a second high-band frequency sub-range based on the resampled
signal. The first excitation signal is generated based on
application of a first function to the resampled signal. The second
excitation signal is generated based on application of a second
function to the resampled signal. The harmonic extension module is
further configured to generate a high-band excitation signal based
on the first excitation signal and the second excitation
signal.
[0024] In another particular aspect, a device includes a receiver
and a harmonic extension module. The receiver is configured to
receive a parameter associated with a bandwidth-extended audio
stream. The harmonic extension module is configured to select one
or more non-linear processing functions based at least in part on a
value of the parameter. The harmonic extension module is also
configured to generate a high-band excitation signal based on the
one or more non-linear processing functions.
[0025] In another particular aspect, a device includes a receiver
and a high-band excitation signal generator. The receiver is
configured to receive a parameter associated with a
bandwidth-extended audio stream. The high-band excitation signal
generator is configured to determine a value of the parameter. The
high-band excitation signal generator is also configured,
responsive to the value of the parameter, to generate a high-band
excitation signal based on target gain information associated with
the bandwidth-extended audio stream or based on filter information
associated with the bandwidth-extended audio stream.
[0026] In another particular aspect, a device includes a receiver
and a high-band excitation signal generator. The receiver is
configured to filter information associated with a
bandwidth-extended audio stream audio stream. The high-band
excitation signal generator is configured to determine a filter
based on the filter information and to generate a modified
high-band excitation signal based on application of the filter to a
first high-band excitation signal.
[0027] In another particular aspect, a device includes a high-band
excitation signal generator configured to generate a modulated
noise signal by applying spectral shaping to a first noise signal
and to generate a high-band excitation signal by combining the
modulated noise signal and a harmonically extended signal.
[0028] In another particular aspect, a device includes a receiver
and a high-band excitation signal generator. The receiver is
configured to receive a low-band voicing factor and a mixing
configuration parameter associated with a bandwidth-extended audio
stream. The high-band excitation signal generator is configured to
determine a high-band mixing configuration based on the low-band
voicing factor and the mixing configuration parameter. The
high-band excitation signal generator is also configured to
generate a high-band excitation signal based on the high-band
mixing configuration.
[0029] In another particular aspect, a signal processing method
includes generating, at a device, a resampled signal based on a
low-band excitation signal. The method also includes generating, at
the device, at least a first excitation signal corresponding to a
first high-band frequency sub-range and a second excitation signal
corresponding to a second high-band frequency sub-range based on
the resampled signal. The first excitation signal is generated
based on application of a first function to the resampled signal.
The second excitation signal is generated based on application of a
second function to the resampled signal. The method also includes
generating, at the device, a high-band excitation signal based on
the first excitation signal and the second excitation signal.
[0030] In another particular aspect, a signal processing method
includes receiving, at a device, a parameter associated with a
bandwidth-extended audio stream. The method also includes
selecting, at the device, one or more non-linear processing
functions based at least in part on a value of the parameter. The
method further includes generating, at the device, a high-band
excitation signal based on the one or more non-linear processing
functions.
[0031] In another particular aspect, a signal processing method
includes receiving, at a device, a parameter associated with a
bandwidth-extended audio stream. The method also includes
determining, at the device, a value of the parameter. The method
further includes, responsive to the value of the parameter,
generating a high-band excitation signal based on target gain
information associated with the bandwidth-extended audio stream or
based on filter information associated with the bandwidth-extended
audio stream.
[0032] In another particular aspect, a signal processing method
includes receiving, at a device, filter information associated with
a bandwidth-extended audio stream audio stream. The method also
includes determining, at the device, a filter based on the filter
information. The method further includes generating, at the device,
a modified high-band excitation signal based on application of the
filter to a first high-band excitation signal.
[0033] In another particular aspect, a signal processing method
includes generating, at a device, a modulated noise signal by
applying spectral shaping to a first noise signal. The method also
includes generating, at the device, a high-band excitation signal
by combining the modulated noise signal and a harmonically extended
signal.
[0034] In another particular aspect, a signal processing method
includes receiving, at a device, a low-band voicing factor and a
mixing configuration parameter associated with a bandwidth-extended
audio stream. The method also includes determining, at the device,
a high-band mixing configuration based on the low-band voicing
factor and the mixing configuration parameter. The method further
includes generating, at the device, a high-band excitation signal
based on the high-band mixing configuration.
[0035] Other aspects, advantages, and features of the present
disclosure will become apparent after review of the entire
application, including the following sections: Brief Description of
the Drawings, Detailed Description, and the Claims.
V. BRIEF DESCRIPTION OF THE DRAWINGS
[0036] FIG. 1 is a block diagram of a particular illustrative
aspect of a system that includes devices that are operable to
generate a high-band signal;
[0037] FIG. 2 is a diagram of another aspect of a system that
includes devices that are operable to generate a high-band
signal;
[0038] FIG. 3 is a diagram of another aspect of a system that
includes devices that are operable to generate a high-band
signal;
[0039] FIG. 4 is a diagram of another aspect of a system that
includes devices that are operable to generate a high-band
signal;
[0040] FIG. 5 is a diagram of a particular illustrative aspect of a
resampler that may be included in one or more of the systems of
FIGS. 1-4;
[0041] FIG. 6 is a diagram of a particular illustrative aspect of
spectral flipping of a signal that may be performed by one or more
of the systems of FIGS. 1-4;
[0042] FIG. 7 is a flowchart to illustrate an aspect of a method of
high band signal generation;
[0043] FIG. 8 is a flowchart to illustrate another aspect of a
method of high band signal generation;
[0044] FIG. 9 is a flowchart to illustrate another aspect of a
method of high band signal generation;
[0045] FIG. 10 is a flowchart to illustrate another aspect of a
method of high band signal generation;
[0046] FIG. 11 is a flowchart to illustrate another aspect of a
method of high band signal generation;
[0047] FIG. 12 is a flowchart to illustrate another aspect of a
method of high band signal generation;
[0048] FIG. 13 is a diagram of another aspect of a system that
includes devices that are operable to generate a high-band
signal;
[0049] FIG. 14 is a diagram of components of the system of FIG.
13;
[0050] FIG. 15 is a diagram to illustrate another aspect of a
method of high-band signal generation;
[0051] FIG. 16 is a diagram to illustrate another aspect of a
method of high-band signal generation;
[0052] FIG. 17 is a diagram of components of the system of FIG.
13;
[0053] FIG. 18 is a diagram to illustrate another aspect of a
method of high-band signal generation;
[0054] FIG. 19 is a diagram of components of the system of FIG.
13;
[0055] FIG. 20 is a diagram to illustrate another aspect of a
method of high-band signal generation;
[0056] FIG. 21 is a flowchart to illustrate another aspect of a
method of high band signal generation;
[0057] FIG. 22 is a flowchart to illustrate another aspect of a
method of high band signal generation;
[0058] FIG. 23 is a flowchart to illustrate another aspect of a
method of high band signal generation;
[0059] FIG. 24 is a flowchart to illustrate another aspect of a
method of high band signal generation;
[0060] FIG. 25 is a flowchart to illustrate another aspect of a
method of high band signal generation;
[0061] FIG. 26 is a block diagram of a device operable to perform
high band signal generation in accordance with the systems and
methods of FIGS. 1-25; and
[0062] FIG. 27 is a block diagram of a base station operable to
perform high band signal generation in accordance with the systems
and methods of FIGS. 1-26.
VI. DETAILED DESCRIPTION
[0063] Referring to FIG. 1, a particular illustrative aspect of a
system that includes devices that are operable to generate a
high-band signal is disclosed and generally designated 100.
[0064] The system 100 includes a first device 102 in communication,
via a network 107, with a second device 104. The first device 102
may include a processor 106. The processor 106 may be coupled to or
may include an encoder 108. The second device 104 may be coupled to
or in communication with one or more speakers 122. The second
device 104 may include a processor 116, a memory 132, or both. The
processor 116 may be coupled to or may include a decoder 118. The
decoder 118 may include a first decoder 134 (e.g., an algebraic
code-excited linear prediction (ACELP) decoder) and a second
decoder 136 (e.g., a time-domain bandwidth extension (TBE)
decoder). In illustrative aspects, one or more techniques described
herein may be included in an industry standard, including but not
limited to a standard for moving pictures experts group (MPEG)-H
three dimensional (3D) audio.
[0065] The second decoder 136 may include a TBE frame converter 156
coupled to a bandwidth extension module 146, a decoding module 162,
or both. The decoding module 162 may include a high-band (HB)
excitation signal generator 147, a HB signal generator 148, or
both. The bandwidth extension module 146 may be coupled, via the
decoding module to a signal generator 138. The first decoder 134
may be coupled to the second decoder 136, the signal generator 138,
or both. For example, the first decoder 134 may be coupled to the
bandwidth extension module 146, the HB excitation signal generator
147, or both. The HB excitation signal generator 147 may be coupled
to the HB signal generator 148. The memory 132 may be configured to
store instructions to perform one or more functions (e.g., a first
function 164, a second function 166, or both). The first function
164 may include a first non-linear function (e.g., a square
function) and the second function 166 may include a second
non-linear function (e.g., an absolute value function) that is
distinct from the first non-linear function. Alternatively, such
functions may be implemented using hardware (e.g., circuitry) at
the second device 104. The memory 132 may be configured to store
one or more signals (e.g., a first excitation signal 168, a second
excitation signal 170, or both). The second device 104 may further
include a receiver 192. In a particular implementation, the
receiver 192 may be included in a transceiver.
[0066] During operation, the first device 102 may receive (or
generate) an input signal 114. The input signal 114 may correspond
to speech of one or more users, background noise, silence, or a
combination thereof. In a particular aspect, the input signal 114
may include data in the frequency range from approximately 50 hertz
(Hz) to approximately 16 kilohertz (kHz). The low-band portion of
the input signal 114 and the high-band portion of the input signal
114 may occupy non-overlapping frequency bands of 50 Hz-7 kHz and 7
kHz-16 kHz, respectively. In an alternate aspect, the low-band
portion and the high-band portion may occupy non-overlapping
frequency bands of 50 Hz-8 kHz and 8 kHz-16 kHz, respectively. In
another alternate aspect, the low-band portion and the high-band
portion may overlap (e.g., 50 Hz-8 kHz and 7 kHz-16 kHz,
respectively).
[0067] The encoder 108 may generate audio data 126 by encoding the
input signal 114. For example, the encoder 108 may generate a first
bit-stream 128 (e.g., an ACELP bit-stream) based on a low-band
signal of the input signal 114. The first bit-stream 128 may
include low-band parameter information (e.g., low-band linear
prediction coefficients (LPCs), low-band line spectral frequencies
(LSFs), or both) and a low-band excitation signal (e.g., a low-band
residual of the input signal 114).
[0068] In a particular aspect, the encoder 108 may generate a
high-band excitation signal and may encode a high-band signal of
the input signal 114 based on the high-band excitation signal. For
example, the encoder 108 may generate a second bit-stream 130
(e.g., a TBE bit-stream) based on the high-band excitation signal.
The second bit-stream 130 may include bit-stream parameters, as
further described with reference to FIG. 3. For example, the
bit-stream parameters may include one or more bit-stream parameters
160 as illustrated in FIG. 1, a non-linear (NL) configuration mode
158, or a combination thereof. The bit-stream parameters may
include high-band parameter information. For example, the second
bit-stream 130 may include at least one of high-band LPC
coefficients, high-band LSF, high-band line spectral pair (LSP)
coefficients, gain shape information (e.g., temporal gain
parameters corresponding to sub-frames of a particular frame), gain
frame information (e.g., gain parameters corresponding to an energy
ratio of high-band to low-band for a particular frame), and/or
other parameters corresponding to a high-band portion of the input
signal 114. In a particular aspect, the encoder 108 may determine
the high-band LPC coefficients using at least one of a vector
quantizer, a hidden markov model (HMM), a gaussian mixture model
(GMM), or another model or method. The encoder 108 may determine
the high-band LSF, the high-band LSP, or both, based on the LPC
coefficients.
[0069] The encoder 108 may generate high-band parameter information
based on the high-band signal of the input signal 114. For example,
a "local" decoder of the first device 102 may emulate the decoder
118 of the second device 104. The "local" decoder may generate a
synthesized audio signal based on the high-band excitation signal.
The encoder 108 may generate gain values (e.g., gain shape, gain
frame, or both) based on a comparison of the synthesized audio
signal and the input signal 114. For example, the gain values may
correspond to a difference between the synthesized audio signal and
the input signal 114. The audio data 126 may include the first
bit-stream 128, the second bit-stream 130, or both. The first
device 102 may transmit the audio data 126 to the second device 104
via the network 107.
[0070] The receiver 192 may receive the audio data 126 from the
first device 102 and may provide the audio data 126 to the decoder
118. The receiver 192 may also store the audio data 126 (or
portions thereof) in the memory 132. In an alternate
implementation, the memory 132 may store the input signal 114, the
audio data 126, or both. In this implementation, the input signal
114, the audio data 126, or both, may be generated by the second
device 104. For example, the audio data 126 may correspond to media
(e.g., music, movies, television shows, etc.) that is stored at the
second device 104 or that is being streamed by the second device
104.
[0071] The decoder 118 may provide the first bit-stream 128 to the
first decoder 134 and the second bit-stream 130 to the second
decoder 136. The first decoder 134 may extract (or decode) low-band
parameter information, such as low-band LPC coefficients, low-band
LSF, or both, and a low-band (LB) excitation signal 144 (e.g., a
low-band residual of the input signal 114) from the first
bit-stream 128. The first decoder 134 may provide the LB excitation
signal 144 to the bandwidth extension module 146. The first decoder
134 may generate a LB signal 140 based on the low-band parameters
and the LB excitation signal 144 using a particular LB model. The
first decoder 134 may provide the LB signal 140 to the signal
generator 138, as shown.
[0072] The first decoder 134 may determine a LB voicing factor (VF)
154 (e.g., a value from 0.0 to 1.0) based on the LB parameter
information. The LB VF 154 may indicate a voiced/unvoiced nature
(e.g., strongly voiced, weakly voiced, weakly unvoiced, or strongly
unvoiced) of the LB signal 140. The first decoder 134 may provide
the LB VF 154 to the HB excitation signal generator 147.
[0073] The TBE frame converter 156 may generate bit-stream
parameters by parsing the second bit-stream 130. For example, the
bit-stream parameters may include the bit-stream parameters 160,
the NL configuration mode 158, or a combination thereof, as further
described with reference to FIG. 3. The TBE frame converter 156 may
provide the NL configuration mode 158 to the bandwidth extension
module 146, the bit-stream parameters 160 to the decoding module
162, or both.
[0074] The bandwidth extension module 146 may generate an extended
signal 150 (e.g., a harmonically extended high-band excitation
signal) based on the LB excitation signal 144, the NL configuration
mode 158, or both, as described with reference to FIGS. 4-5. The
bandwidth extension module 146 may provide the extended signal 150
to the HB excitation signal generator 147. The HB excitation signal
generator 147 may synthesize a HB excitation signal 152 based on
the bit-stream parameters 160, the extended signal 150, the LB VF
154, or a combination thereof, as further described with reference
to FIG. 4. The HB signal generator 148 may generate an HB signal
142 based on the HB excitation signal 152, the bit-stream
parameters 160, or a combination thereof, as further described with
reference to FIG. 4. The HB signal generator 148 may provide the HB
signal 142 to the signal generator 138.
[0075] The signal generator 138 may generate an output signal 124
based on the LB signal 140, the HB signal 142, or both. For
example, the signal generator 138 may generate an upsampled HB
signal by upsampling the HB signal 142 by a particular factor
(e.g., 2). The signal generator 138 may generate a spectrally
flipped HB signal by spectrally flipping the upsampled HB signal in
a time-domain, as described with reference to FIG. 6. The
spectrally flipped HB signal may correspond to a high-band (e.g.,
32 kHz) signal. The signal generator 138 may generate an upsampled
LB signal by upsampling the LB signal 140 by a particular factor
(e.g., 2). The upsampled LB signal may correspond to a 32 kHz
signal. The signal generator 138 may generate a delayed HB signal
by delaying the spectrally flipped HB signal to time-align the
delayed HB signal and the upsampled LB signal. The signal generator
138 may generate the output signal 124 by combining the delayed HB
signal and the upsampled LB signal. The signal generator 138 may
store the output signal 124 in the memory 132. The signal generator
138 may output, via the speakers 122, the output signal 124.
[0076] Referring to FIG. 2, a system is disclosed and generally
designated 200. In a particular aspect, the system 200 may
correspond to the system 100 of FIG. 1. The system 200 may include
a resampler and filterbank 202, the encoder 108, or both. The
resampler and filterbank 202, the encoder 108, or both, may be
included in the first device 102 of FIG. 1. The encoder 108 may
include a first encoder 204 (e.g., an ACELP encoder) and a second
encoder 296 (e.g., a TBE encoder). The second encoder 296 may
include an encoder bandwidth extension module 206, an encoding
module 208 (e.g., a TBE encoder), or both. The encoder bandwidth
extension module 206 may perform non-linear processing and
modeling, as described with reference to FIG. 13. In a particular
aspect, a receiving/decoding device may be coupled to or may
include media storage 292. For example, the media storage 292 may
store encoded media. Audio for the encoded media may be represented
by an ACELP bit-stream and a TBE bit-stream. Alternatively, the
media storage 292 may correspond to a network accessible server
from which the ACELP bit-stream and the TBE bit-stream are received
during a streaming session.
[0077] The system 200 may include the first decoder 134, the second
decoder 136, the signal generator 138 (e.g., a resampler, a delay
adjuster, and a mixer), or a combination thereof. The second
decoder 136 may include the bandwidth extension module 146, the
decoding module 162, or both. The bandwidth extension module 146
may perform non-linear processing and modeling, as described with
reference to FIGS. 1 and 4.
[0078] During operation, the resampler and filterbank 202 may
receive the input signal 114. The resampler and filterbank 202 may
generate a first LB signal 240 by applying a low-pass filter to the
input signal 114 and may provide the first LB signal 240 to the
first encoder 204. The resampler and filterbank 202 may generate a
first HB signal 242 by applying a high-pass filter to the input
signal 114 and may provide the first HB signal 242 to the encoding
module 208.
[0079] The first encoder 204 may generate a first LB excitation
signal 244 (e.g., an LB residual), the first bit-stream 128, or
both, based on the first LB signal 240. The first encoder 204 may
provide the first LB excitation signal 244 to the encoder bandwidth
extension module 206. The first encoder 204 may provide the first
bit-stream 128 to the first decoder 134.
[0080] The encoder bandwidth extension module 206 may generate a
first extended signal 250 based on the first LB excitation signal
244. The encoder bandwidth extension module 206 may provide the
first extended signal 250 to the encoding module 208. The encoding
module 208 may generate the second bit-stream 130 based on the
first HB signal 242 and the first extended signal 250. For example,
the encoding module 208 may generate a synthesized HB signal based
on the first extended signal 250, may generate the bit-stream
parameters 160 of FIG. 1 to reduce a difference between the
synthesized HB signal and the first HB signal 242, and may generate
the second bit-stream 130 including the bit-stream parameters
160.
[0081] The first decoder 134 may receive the first bit-stream 128
from the first encoder 204. The decoding module 162 may receive the
second bit-stream 130 from the encoding module 208. In a particular
implementation, the first decoder 134 may receive the first
bit-stream 128, the second bit-stream 130, or both, from the media
storage 292. For example, the first bit-stream 128, the second
bit-stream 130, or both, may correspond to media (e.g., music or a
movie) stored at the media storage 292. In a particular aspect, the
media storage 292 may correspond to a network device that is
streaming the first bit-stream 128 to the first decoder 134 and the
second bit-stream 130 to the decoding module 162. The first decoder
134 may generate the LB signal 140, the LB excitation signal 144,
or both, based on the first bit-stream 128, as described with
reference to FIG. 1. The LB signal 140 may include a synthesized LB
signal that approximates the first LB signal 240. The first decoder
134 may provide the LB signal 140 to the signal generator 138. The
first decoder 134 may provide the LB excitation signal 144 to the
bandwidth extension module 146. The bandwidth extension module 146
may generate the extended signal 150 based on the LB excitation
signal 144, as described with reference to FIG. 1. The bandwidth
extension module 146 may provide the extended signal 150 to the
decoding module 162. The decoding module 162 may generate the HB
signal 142 based on the second bit-stream 130 and the extended
signal 150, as described with reference to FIG. 1. The HB signal
142 may include a synthesized HB signal that approximates the first
HB signal 242. The decoding module 162 may provide the HB signal
142 to the signal generator 138. The signal generator 138 may
generate the output signal 124 based on the LB signal 140 and the
HB signal 142, as described with reference to FIG. 1.
[0082] Referring to FIG. 3, a system is disclosed and generally
designated 300. In a particular aspect, the system 300 may
correspond to the system 100 of FIG. 1, the system 200 of FIG. 2,
or both. The system 300 may include the first decoder 134, the TBE
frame converter 156, the bandwidth extension module 146, the
decoding module 162, or a combination thereof. The first decoder
134 may include an ACELP decoder, a MPEG decoder, an MPEG-H 3D
audio decoder, a linear prediction domain (LPD) decoder, or a
combination thereof.
[0083] During operation, the TBE frame converter 156 may receive
the second bit-stream 130, as described with reference to FIG. 1.
The second bit-stream 130 may correspond to a data structure
tbe_data( ) illustrated in Table 1:
TABLE-US-00001 TABLE 1 Syntax No. of bits tbe_data( ) { tbe_heMode;
1 idxFrameGain; 5 idxSubGains; 5 lsf_idx[0]; 7 lsf_idx[1]; 7 if
(tbe_heMode==0) { tbe_hrConfig; 1 tbe_nlConfig; 1 idxMixConfig; 2
if (tbe_hrConfig==1) { idxShbFrGain; 6 idxResSubGains; 5 } else {
idxShbExcResp[0]; 7 idxShbExcResp[1]; 4 } } }
[0084] The TBE frame converter 156 may generate the bit-stream
parameters 160, the NL configuration mode 158, or a combination
thereof, by parsing the second bit-stream 130. The bit-stream
parameters 160 may include a high-efficiency (HE) mode 360 (e.g.,
tbe_heMode), gain information 362 (e.g., idxFrameGain and
idxSubGains), HB LSF data 364 (e.g., lsf_idx[0,1]), a high
resolution (HR) configuration mode 366 (e.g., tbe_hrConfig), a mix
configuration mode 368 (e.g., idxMixConfig, alternatively referred
to as a "mixing configuration parameter"), HB target gain data 370
(e.g., idxShbFrGain), gain shape data 372 (e.g., idxResSubGains),
filter information 374 (e.g., idxShbExcResp[0,1]), or a combination
thereof. The TBE frame converter 156 may provide the NL
configuration mode 158 to the bandwidth extension module 146. The
TBE frame converter 156 may also provide one or more of the
bit-stream parameters 160 to the decoding module 162, as shown.
[0085] In a particular aspect, the filter information 374 may
indicate a finite impulse response (FIR) filter. The gain
information 362 may include HB reference gain information, temporal
sub-frame residual gain shape information, or both. The HB target
gain data 370 may indicate frame energy.
[0086] In a particular aspect, the TBE frame converter 156 may
extract the NL configuration mode 158 from the second bit-stream
130 in response to determining that the HE mode 360 has a first
value (e.g., 0). Alternatively, the TBE frame converter 156 may set
the NL configuration mode 158 to a default value (e.g., 1) in
response to determining that the HE mode 360 has a second value
(e.g., 1). In a particular aspect, the TBE frame converter 156 may
set the NL configuration mode 158 to the default value (e.g., 1) in
response to determining that the NL configuration mode 158 has a
first particular value (e.g., 2) and that the mix configuration
mode 368 has a second particular value (e.g., a value greater than
1).
[0087] In a particular aspect, the TBE frame converter 156 may
extract the HR configuration mode 366 from the second bit-stream
130 in response to determining that the HE mode 360 has the first
value (e.g., 0). Alternatively, the TBE frame converter 156 may set
the HR configuration mode 366 to a default value (e.g., 0) in
response to determining that the HE mode 360 has the second value
(e.g., 1). The first decoder 134 may receive the first bit-stream
128, as described with reference to FIG. 1.
[0088] Referring to FIG. 4, a system is disclosed and generally
designated 400. In a particular aspect, the system 400 may
correspond to the system 100 of FIG. 1, the system 200 of FIG. 2,
the system 300 of FIG. 3, or a combination thereof. The system 400
may include the bandwidth extension module 146, the HB excitation
signal generator 147, the HB signal generator 148, or a combination
thereof. The bandwidth extension module 146 may include a resampler
402, a harmonic extension module 404, or both. The HB excitation
signal generator 147 may include a spectral flip and decimation
module 408, an adaptive whitening module 410, a temporal envelope
modulator 412, an HB excitation estimator 414, or a combination
thereof. The HB signal generator 148 may include an HB linear
prediction module 416, a synthesis module 418, or both.
[0089] During operation, the bandwidth extension module 146 may
generate the extended signal 150 by extending the LB excitation
signal 144, as described herein. The resampler 402 may receive the
LB excitation signal 144 from the first decoder 134 of FIG. 1, such
as ACELP decoder. The resampler 402 may generate a resampled signal
406 based on the LB excitation signal 144, as described with
reference to FIG. 5. The resampler 402 may provide the resampled
signal 406 to the harmonic extension module 404.
[0090] The harmonic extension module 404 may receive the NL
configuration mode 158 from the TBE frame converter 156 of FIG. 1.
The harmonic extension module 404 may generate the extended signal
150 (e.g., an HB excitation signal) by harmonically extending the
resampled signal 406 in a time-domain based on the NL configuration
mode 158. In a particular aspect, the harmonic extension module 404
may generate the extended signal 150 (E.sub.HE) based on Equation
1:
E H .times. E = { E L .times. B , if .times. .times. .times.
tbe_nlConfig = 1 N .times. sign .function. ( E L .times. B )
.times. E L .times. B 2 , if .times. .times. tbe_nlConfig = 0 H L
.times. P .function. ( z ) .times. N .times. sign .function. ( E L
.times. B ) .times. E L .times. B 2 + H H .times. P .times. E L
.times. B , if .times. .times. tbe_nlConfig = 0 .times. .times. AND
.times. .times. idxMixConfi .times. g .times. .ltoreq. 1 , Equation
.times. .times. 1 ##EQU00001##
where E.sub.LB corresponds to the resampled signal 406,
.epsilon..sub.N corresponds to an energy normalization factor
between E.sub.LB and E.sub.LB.sup.2, and tbe_nlConfig corresponds
to the NL configuration mode 158. The energy normalization factor
may correspond to a ratio of frame energies of E.sub.LB and
E.sub.LB.sup.2. H.sub.LP and H.sub.HP correspond to a low-pass
filter and high-pass filter respectively, with a particular cut-off
frequency (e.g., 3/4 f.sub.s or approximately 12 kHz). A transfer
function of the H.sub.LP may be based on Equation 2:
H L .times. P .function. ( z ) = 0 . 5 .times. 7 .times. ( 1 + 2
.times. z - 1 + z - 2 ) 1 + 0.94 .times. z - 1 + 0 . 3 .times. 3
.times. z - 2 , Equation .times. .times. 2 ##EQU00002##
[0091] A transfer function of the H.sub.HP may be based on Equation
3:
H H .times. P .function. ( z ) = 0 . 0 .times. 9 .times. 8 .times.
( 1 - 2 .times. z - 1 + z - 2 ) 1 + 0.94 .times. z - 1 + 0 .times.
3 .times. 3 .times. z - 2 , Equation .times. .times. 3
##EQU00003##
[0092] For example, the harmonic extension module 404 may select
the first function 164, the second function 166, or both, based on
a value of the NL configuration mode 158. To illustrate, the
harmonic extension module 404 may select the first function 164
(e.g., a square function) in response to determining that the NL
configuration mode 158 has a first value (e.g., NL_HARMONIC or 0).
The harmonic extension module 404 may, in response to selecting the
first function 164, generate the extended signal 150 by applying
the first function 164 (e.g., the square function) to the resampled
signal 406. The square function may preserve the sign information
of the resampled signal 406 in the extended signal 150 and may
square values of the resampled signal 406.
[0093] In a particular aspect, the harmonic extension module 404
may select the second function 166 (e.g., an absolute value
function) in response to determining that the NL configuration mode
158 has a second value (e.g., NL_SMOOTH or 1). The harmonic
extension module 404 may, in response to selecting the second
function 166, generate the extended signal 150 by applying the
second function 166 (e.g., the absolute value function) to the
resampled signal 406.
[0094] In a particular aspect, the harmonic extension module 404
may select a hybrid function in response to determining that the NL
configuration mode 158 has a third value (e.g., NL_HYBRID or 2). In
this aspect, the TBE frame converter 156 may provide the mix
configuration mode 368 to the harmonic extension module 404. The
hybrid function may include a combination of multiple functions
(e.g., the first function 164 and the second function 166).
[0095] The harmonic extension module 404 may, in response to
selecting the hybrid function, generate a plurality of excitation
signals (e.g., at least the first excitation signal 168 and the
second excitation signal 170) corresponding to a plurality of
high-band frequency sub-ranges based on the resampled signal 406.
For example, the harmonic extension module 404 may generate the
first excitation signal 168 by applying the first function 164 to
the resampled signal 406 or a portion thereof. The first excitation
signal 168 may correspond to a first high-band frequency sub-range
(e.g., approximately 8-12 kHz). The harmonic extension module 404
may generate the second excitation signal 170 by applying the
second function 166 to the resampled signal 406 or a portion
thereof. The second excitation signal 170 may correspond to a
second high-band frequency sub-range (e.g., approximately 12-16
kHz).
[0096] The harmonic extension module 404 may generate a first
filtered signal by applying a first filter (e.g., a low-pass
filter, such as a 8-12 kHz filter) to the first excitation signal
168 and may generate a second filtered signal by applying a second
filter (e.g., a high-pass filter, such as a 12-16 kHz filter) to
the second excitation signal 170. The first filter and the second
filter may have a particular cut-off frequency (e.g., 12 kHz). The
harmonic extension module 404 may generate the extended signal 150
by combining the first filtered signal and the second filtered
signal. The first high-band frequency sub-range (e.g.,
approximately 8-12 kHz) may correspond to harmonic data (e.g.,
weakly voiced or strongly voiced). The second high-band frequency
sub-range (e.g., approximately 12-16 kHz) may correspond to
noise-like data (e.g., weakly unvoiced or strongly unvoiced). The
harmonic extension module 404 may thus use distinct non-linear
processing functions for distinct bands in the spectrum.
[0097] In a particular implementation, the harmonic extension
module 404 may select the second function 166 in response to
determining that the NL configuration mode 158 has the second value
(e.g., NL_SMOOTH or 1) and that the mix configuration mode 368 has
a particular value (e.g., a value greater than 1). Alternatively,
the harmonic extension module 404 may select the hybrid function in
response to determining that the NL configuration mode 158 has the
second value (e.g., NL_SMOOTH or 1) and that the mix configuration
mode 368 has another particular value (e.g., a value less than or
equal to 1).
[0098] In a particular aspect, the harmonic extension module 404
may, in response to determining that the HE mode 360 has the first
value (e.g., 0), generate the extended signal 150 (e.g., an HB
excitation signal) by harmonically extending the resampled signal
406 in a time-domain based on the NL configuration mode 158. The
harmonic extension module 404 may, in response to determining that
the HE mode 360 has the second value (e.g., 1), generate the extend
signal 150 (e.g., an HB excitation signal) by harmonically
extending the resampled signal 406 in a time-domain based on the
gain information 362 (e.g., idxSubGains). For example, the harmonic
extension module 404 may generate the extended signal 150 using the
tbe_nlConfig=1 configuration (e.g., E.sub.HE=|E.sub.LB) in response
to determining that the gain information 362 (e.g., idxSubGains)
corresponds to a particular value (e.g., an odd value) and may
generate the extended signal 150 using the tbe_nlConfig=0
configuration (e.g.,
E.sub.HE=.epsilon..sub.Nsign(E.sub.LB)E.sub.LB.sup.2) otherwise. To
illustrate, the harmonic extension module 404 may, in response to
determining that the gain information 362 (e.g., idxSubGains) does
not correspond to the particular value (e.g., an odd value) or that
the gain information 362 (e.g., idxSubGains) corresponds to another
value (e.g., an even value), may generate the extended signal 150
using the tbe_nlConfig=0 configuration (e.g.,
E.sub.HE=.epsilon..sub.Nsign(E.sub.LB)E.sub.LB.sup.2).
[0099] The harmonic extension module 404 may provide the extended
signal 150 to the spectral flip and decimation module 408. The
spectral flip and decimation module 408 may generate a spectrally
flipped signal by performing spectral flipping of the extended
signal 150 in the time-domain based on Equation 4:
E.sub.HE.sup.f(n)=(-1).sup.nE.sub.HE(n), n=0,1,2, . . . ,N-1,
Equation 4
where E.sub.HE.sup.f(n) corresponds to the spectrally flipped
signal and N (e.g., 512) corresponds to a number of samples per
frame.
[0100] The spectral flip and decimation module 408 may generate a
first signal 450 (e.g., a HB excitation signal) by decimating the
spectrally flipped signal based on a first all-pass filter and a
second all-pass filter. The first all-pass filter may correspond to
a first transfer function indicated by Equation 5:
H A .times. P .times. 1 .function. ( z ) = ( a 0 , 1 + z - 1 1 + a
0 , 1 .times. z - 1 ) .times. ( a 1 , 1 + z - 1 1 + a 1 , 1 .times.
z - 1 ) .times. ( a 2 , 1 + z - 1 1 + a 2 , 1 .times. z - 1 ) .
Equation .times. .times. 5 ##EQU00004##
[0101] The second all-pass filter may correspond to a second
transfer function indicated by Equation 6:
H A .times. P .times. 2 .function. ( z ) = ( a 0 , 2 + z - 1 1 + a
0 , 2 .times. z - 1 ) .times. ( a 1 , 2 + z - 1 1 + a 1 , 2 .times.
z - 1 ) .times. ( a 2 , 2 + z - 1 1 + a 2 , 2 .times. z - 1 ) .
Equation .times. .times. 6 ##EQU00005##
[0102] Exemplary values of the all-pass filter coefficients are
provided in Table 2 below:
TABLE-US-00002 TABLE 2 a.sub.0, 1 0.06056541924291 a.sub.1, 1
0.42943401549235 a.sub.2, 1 0.80873048306552 a.sub.0, 2
0.22063024829630 a.sub.1, 2 0.63593943961708 a.sub.2, 2
0.94151583095682
[0103] The spectral flip and decimation module 408 may generate a
first filtered signal by applying the first all-pass filter to
filter even samples of the spectrally flipped signal. The spectral
flip and decimation module 408 may generate a second filtered
signal by applying the second all-pass filter to filter odd samples
of the spectrally flipped signal. The spectral flip and decimation
module 408 may generate the first signal 450 by averaging the first
filtered signal and the second filtered signal.
[0104] The spectral flip and decimation module 408 may provide the
first signal 450 to the adaptive whitening module 410. The adaptive
whitening module 410 may generate a second signal 452 (e.g., an HB
excitation signal) by flattening a spectrum of the first signal 450
by performing fourth-order LP whitening of the first signal 450.
For example, the adaptive whitening module 410 may estimate
auto-correlation coefficients of the first signal 450. The adaptive
whitening module 410 may generate first coefficients by applying
bandwidth expansion to the auto-correlation coefficients based on
multiplying the auto-correlation coefficients by an expansion
function. The adaptive whitening module 410 may generate first LPCs
by applying an algorithm (e.g., a Levinson-Durbin algorithm) to the
first coefficients. The adaptive whitening module 410 may generate
the second signal 452 by inverse filtering the first LPCs.
[0105] In a particular implementation, the adaptive whitening
module 410 may modulate the second signal 452 based on normalized
residual energy in response to determining that the HR
configuration mode 366 has a particular value (e.g., 1). The
adaptive whitening module 410 may determine the normalized residual
energy based on the gain shape data 372. Alternatively, the
adaptive whitening module 410 may filter the second signal 452
based on a particular filter (e.g., a FIR filter) in response to
determining that the HR configuration mode 366 has a first value
(e.g., 0). The adaptive whitening module 410 may determine (or
generate) the particular filter based on the filter information
374. The adaptive whitening module 410 may provide the second
signal 452 to the temporal envelope modulator 412, the HB
excitation estimator 414, or both.
[0106] The temporal envelope modulator 412 may receive the second
signal 452 from the adaptive whitening module 410, a noise signal
440 from a random noise generator, or both. The random noise
generator may be coupled to or may be included in the second device
104. The temporal envelope modulator 412 may generate a third
signal 454 based on the noise signal 440, the second signal 452, or
both. For example, the temporal envelope modulator 412 may generate
a first noise signal by applying temporal shaping to the noise
signal 440. The temporal envelope modulator 412 may generate a
signal envelope based on the second signal 452 (or the LB
excitation signal 144). The temporal envelope modulator 412 may
generate the first noise signal based on the signal envelope and
the noise signal 440. For example, the temporal envelope modulator
412 may combine the signal envelope and the noise signal 440.
Combining the signal envelope and the noise signal 440 may modulate
amplitude of the noise signal 440. The temporal envelope modulator
412 may generate the third signal 454 by applying spectral shaping
to the first noise signal. In an alternate implementation, the
temporal envelope modulator 412 may generate the first noise signal
by applying spectral shaping to the noise signal 440 and may
generate the third signal 454 by applying temporal shaping to the
first noise signal. Thus, spectral and temporal shaping may be
applied in any order to the noise signal 440. The temporal envelope
modulator 412 may provide the third signal 454 to the HB excitation
estimator 414.
[0107] The HB excitation estimator 414 may receive the second
signal 452 from the adaptive whitening module 410, the third signal
454 from the temporal envelope modulator 412, or both. The HB
excitation estimator 414 may generate the HB excitation signal 152
by combining the second signal 452 and the third signal 454.
[0108] In a particular aspect, the HB excitation estimator 414 may
combine the second signal 452 and the third signal 454 based on the
LB VF 154. For example, the HB excitation estimator 414 may
determine a HB VF based on one or more LB parameters. The HB VF may
correspond to a HB mixing configuration. The one or more LB
parameters may include the LB VF 154. The HB excitation estimator
414 may determine the HB VF based on application of a sigmoid
function on the LB VF 154. For example, the HB excitation estimator
414 may determine the HB VF based on Equation 7:
V .times. F i = 1 1 + e - 4 .times. .alpha. .times. i , i = 1 , 2 ,
3 , 4 , Equation .times. .times. 7 ##EQU00006##
[0109] where VF.sub.i may correspond to a HB VF corresponding to a
sub-frame i, and al may correspond to a normalized correlation from
the LB. In a particular aspect, at may correspond to the LB VF 154
for the sub-frame i. The HB excitation estimator 414 may "smoothen"
the HB VF to account for sudden variations in the LB VF 154. For
example the HB excitation estimator 414 may reduce variations in
the HB VF based on the mix configuration mode 368 in response to
determining that the HR configuration mode 366 has a particular
value (e.g., 1). Modifying the HB VF based on the mix configuration
mode 368 may compensate for a mismatch between the LB VF 154 and
the HB VF. The HB excitation estimator 414 may power normalize the
third signal 454 so that the third signal 454 has the same power
level as the second signal 452.
[0110] The HB excitation estimator 414 may determine a first weight
(e.g., HB VF) and a second weight (e.g., 1-HB VF). The HB
excitation estimator 414 may generate the HB excitation signal 152
by performing a weighted sum of the second signal 452 and the third
signal 454, where the first weight is assigned to the second signal
452 and the second weight is assigned to the third signal 454. For
example, the HB excitation estimator 414 may generate sub-frame (i)
of the HB excitation signal 152 by mixing sub-frame (i) of the
second signal 452 that is scaled based on VF.sub.i (e.g., scaled
based on a square root of VF.sub.i) and sub-frame (i) of the third
signal 454 that is scaled based on (1-VF.sub.i) (e.g., scaled based
on a square root of (1-VF.sub.i)). The HB excitation estimator 414
may provide the HB excitation signal 152 to the synthesis module
418.
[0111] The HB linear prediction module 416 may receive the
bit-stream parameters 160 from the TBE frame converter 156. The HB
linear prediction module 416 may generate LSP coefficients 456
based on the HB LSF data 364. For example, the HB linear prediction
module 416 may determine LSFs based on the HB LSF data 364 and may
convert the LSFs to the LSP coefficients 456. The bit-stream
parameters 160 may correspond to a first audio frame of a sequence
of audio frames. The HB linear prediction module 416 may
interpolate the LSP coefficients 456 based on second LSP
coefficients associated with another frame in response to
determining that the other frame corresponds to a TBE frame. The
other frame may precede the first audio frame in the sequence of
audio frames. The LSP coefficients 456 may be interpolated over a
particular number of (e.g., four) sub-frames. The HB linear
prediction module 416 may refrain from interpolating the LSP
coefficients 456 in response to determining that the other frame
does not correspond to a TBE frame. The HB linear prediction module
416 may provide the LSP coefficients 456 to the synthesis module
418.
[0112] The synthesis module 418 may generate the HB signal 142
based on the LSP coefficients 456, the HB excitation signal 152, or
both. For example, the synthesis module 418 may generate (or
determine) high-band synthesis filters based on the LSP
coefficients 456. The synthesis module 418 may generate a first HB
signal by applying the high-band synthesis filters to the HB
excitation signal 152. The synthesis module 418 may, in response to
determining that the HR configuration mode 366 has a particular
value (e.g., 1), perform a memory-less synthesis to generate the
first HB signal. For example, the first HB signal may be generated
with past LP filter memories set to zero. The synthesis module 418
may match energy of the first HB signal to target signal energy
indicated by the HB target gain data 370. The gain information 362
may include frame gain information and gain shape information. The
synthesis module 418 may generate scaled HB signal by scaling the
first HB signal based on the gain shape information. The synthesis
module 418 may generate the HB signal 142 by multiplying the scaled
HB signal by gain frame indicated by the frame gain information.
The synthesis module 418 may provide the HB signal 142 to the
signal generator 138 of FIG. 1.
[0113] In a particular implementation, the synthesis module 418 may
modify the HB excitation signal 152 prior to generating the first
HB signal. For example, the synthesis module 418 may generate a
modified HB excitation signal based on the HB excitation signal 152
and may generate the first HB signal by applying the high-band
synthesis filters to the modified HB excitation signal. To
illustrate, the synthesis module 418 may, in response to
determining that the HR configuration mode 366 has a first value
(e.g., 0), generate a filter (e.g., a FIR filter) based on the
filter information 374. The synthesis module 418 may generate the
modified HB excitation signal by applying the filter to at least a
portion (e.g., a harmonic portion) of the HB excitation signal 152.
Applying the filter to the HB excitation signal 152 may reduce
distortion between the HB signal 142 generated at the second device
104 and an HB signal of the input signal 114. Alternatively, the
synthesis module 418 may, in response to determining that the HR
configuration mode 366 has a second value (e.g., 1), generate the
modified HB excitation signal based on target gain information. The
target gain information may include the gain shape data 372, the HB
target gain data 370, or both.
[0114] In a particular implementation, the HB excitation estimator
414 may modify the second signal 452 prior to generating the HB
excitation signal 152. For example, the HB excitation estimator 414
may generate a modified second signal based on the second signal
452 and may generate the HB excitation signal 152 by combining the
modified second signal and the third signal 454. To illustrate, the
HB excitation estimator 414 may, in response to determining that
the HR configuration mode 366 has a first value (e.g., 0), generate
a filter (e.g., a FIR filter) based on the filter information 374.
The HB excitation estimator 414 may generate the modified second
signal by applying the filter to at least a portion (e.g., a
harmonic portion) of the second signal 452. Alternatively, the HB
excitation estimator 414 may, in response to determining that the
HR configuration mode 366 has a second value (e.g., 1), generate
the modified second signal based on target gain information. The
target gain information may include the gain shape data 372, the HB
target gain data 370, or both.
[0115] Referring to FIG. 5, the resampler 402 is shown. The
resampler 402 may include a first scaling module 502, a resampling
module 504, an adder 514, a second scaling module 508, or a
combination thereof.
[0116] During operation, the first scaling module 502 may receive
the LB excitation signal 144 and may generate a first scaled signal
510 by scaling the LB excitation signal 144 based on a fixed
codebook (FCB) gain (g.sub.c). The first scaling module 502 may
provide the first scaled signal 510 to the resampling module 504.
The resampling module 504 may generate a resampled signal 512 by
upsampling the first scaled signal 510 by a particular factor
(e.g., 2). The resampling module 504 may provide the resampled
signal 512 to the adder 514. The second scaling module 508 may
generate a second scaled signal 516 by scaling a second resampled
signal 515 based on a pitch gain (g.sub.p). The second resampled
signal 515 may correspond to a previous resampled signal. For
example, the resampled signal 406 may correspond to an nth audio
frame of a sequence of frames. The previous resampled signal may
correspond to the (n-1)th audio frame of the sequence of frames.
The second scaling module 508 may provide the second scaled signal
516 to the adder 514. The adder 514 may combine the resampled
signal 512 and the second scaled signal 516 to generate the
resampled signal 406. The adder 514 may provide the resampled
signal 406 to the second scaling module 508 to be used during
processing of the (n+1)th audio frame. The adder 514 may provide
the resampled signal 406 to the harmonic extension module 404 of
FIG. 4.
[0117] Referring to FIG. 6, a diagram is shown and generally
designated 600. The diagram 600 may illustrate spectral flipping of
a signal. The spectral flipping of the signal may be performed by
one or more of the systems of FIGS. 1-4. For example, the signal
generator 138 may perform a spectral flipping of the high-band
signal 142 in the time-domain, as described with reference to FIG.
1. The diagram 600 includes a first graph 602 and a second graph
604.
[0118] The first graph 602 may correspond to a first signal prior
to spectral flipping. The first signal may correspond to the
high-band signal 142. For example, the first signal may include an
upsampled HB signal generated by upsampling the high-band signal
142 by a particular factor (e.g., 2), as described with reference
to FIG. 1. The second graph 604 may correspond to a spectrally
flipped signal generated by spectrally flipping the first signal.
For example, the spectrally flipped signal may be generated by
spectrally flipping the upsampled HB signal in a time-domain. The
first signal may be flipped at a particular frequency (e.g.,
f.sub.s/2 or approximately 8 kHz). Data of the first signal in a
first frequency range (e.g., 0-f.sub.s/2) may correspond to second
data of the spectrally flipped signal in a second frequency range
(e.g., f.sub.s-f.sub.s/2).
[0119] Referring to FIG. 7, a flowchart of an aspect of a method of
high band signal generation is shown and generally designated 700.
The method 700 may be performed by one or more components of the
systems 100-400 of FIGS. 1-4. For example, the method 700 may be
performed by the second device 104, the bandwidth extension module
146 of FIG. 1, the resampler 402, the harmonic extension module 404
of FIG. 4, or a combination thereof.
[0120] The method 700 includes generating, at a device, a resampled
signal based on a low-band excitation signal, at 702. For example,
the resampler 402 may generate the resampled signal 406, as
described with reference to FIG. 4.
[0121] The method 700 also includes generating, at the device, at
least a first excitation signal corresponding to a first high-band
frequency sub-range and a second excitation signal corresponding to
a second high-band frequency sub-range based on the resampled
signal, at 704. For example, the harmonic extension module 404 may
generate at least the first excitation signal 168 and the second
excitation signal 170 based on the resampled signal 406, as
described with reference to FIG. 4. The first excitation signal 168
may correspond to a first high-band frequency sub-range (e.g., 8-12
kHz). The second excitation signal 170 may correspond to a second
high-band frequency sub-range (e.g., 12-16 kHz). The harmonic
extension module 404 may generate the first excitation signal 168
based on application of the first function 164 to the resampled
signal 406. The harmonic extension module 404 may generate the
second excitation signal 170 based on application of the second
function 166 to the resampled signal 406.
[0122] The method 700 further includes generating, at the device, a
high-band excitation signal based on the first excitation signal
and the second excitation signal, at 706. For example, the harmonic
extension module 404 may generate the extended signal 150 based on
the first excitation signal 168 and the second excitation signal
170, as described with reference to FIG. 4.
[0123] Referring to FIG. 8, a flowchart of an aspect of a method of
high band signal generation is shown and generally designated 800.
The method 800 may be performed by one or more components of the
systems 100-400 of FIGS. 1-4. For example, the method 800 may be
performed by the second device 104, the receiver 192, the bandwidth
extension module 146 of FIG. 1, the harmonic extension module 404
of FIG. 4, or a combination thereof.
[0124] The method 800 includes receiving, at a device, a parameter
associated with a bandwidth-extended audio stream, at 802. For
example, the receiver 192 may receive the NL configuration mode 158
associated with the audio data 126, as described with reference to
FIGS. 1 and 3.
[0125] The method 800 also includes selecting, at the device, one
or more non-linear processing functions based at least in part on a
value of the parameter, at 804. For example, the harmonic extension
module 404 may select the first function 164, the second function
166, or both, based at least in part on a value of the NL
configuration mode 158.
[0126] The method 800 further includes generating, at the device, a
high-band excitation signal based on the one or more non-linear
processing functions, at 806. For example, the harmonic extension
module 404 may generate the extended signal 150 based on the first
function 164, the second function 166, or both.
[0127] Referring to FIG. 9, a flowchart of an aspect of a method of
high band signal generation is shown and generally designated 900.
The method 900 may be performed by one or more components of the
systems 100-400 of FIGS. 1-4. For example, the method 900 may be
performed by the second device 104, the receiver 192, the HB
excitation signal generator 147, the decoding module 162, the
second decoder 136, the decoder 118, the processor 116 of FIG. 1,
or a combination thereof.
[0128] The method 900 includes receiving, at a device, a parameter
associated with a bandwidth-extended audio stream, at 902. For
example, the receiver 192 may receive the HR configuration mode 366
associated with the audio data 126, as described with reference to
FIGS. 1 and 3.
[0129] The method 900 also includes determining, at the device, a
value of the parameter, at 904. For example, the synthesis module
418 may determine a value of the HR configuration mode 366, as
described with reference to FIG. 4.
[0130] The method 900 further includes, responsive to the value of
the parameter, generating a high-band excitation signal based on
target gain information associated with the bandwidth-extended
audio stream or based on filter information associated with the
bandwidth-extended audio stream, at 906. For example, when the
value of the HR configuration mode 366 is 1, the synthesis module
418 may generate a modified excitation signal based on target gain
information, such as one or more of the gain shape data 372, the HB
target gain data 370, or the gain information 362, as described
with reference to FIG. 4. When the value of the HR configuration
mode 366 is 0, the synthesis module 418 may generate the modified
excitation signal based on the filter information 374, as described
with reference to FIG. 4.
[0131] Referring to FIG. 10, a flowchart of an aspect of a method
of high band signal generation is shown and generally designated
1000. The method 1000 may be performed by one or more components of
the systems 100-400 of FIGS. 1-4. For example, the method 1000 may
be performed by the second device 104, the receiver 192, the HB
excitation signal generator 147 of FIG. 1, or a combination
thereof.
[0132] The method 1000 includes receiving, at a device, filter
information associated with a bandwidth-extended audio stream audio
stream, at 1002. For example, the receiver 192 may receive the
filter information 374 associated with the audio data 126, as
described with reference to FIGS. 1 and 3.
[0133] The method 1000 also includes determining, at the device, a
filter based on the filter information, at 1004. For example, the
synthesis module 418 may determine a filter (e.g., FIR filter
coefficients) based on the filter information 374, as described
with reference to FIG. 4.
[0134] The method 1000 further includes generating, at the device,
a modified high-band excitation signal based on application of the
filter to a first high-band excitation signal, at 1006. For
example, the synthesis module 418 may generate a modified high band
excitation signal based on application of the filter to the HB
excitation signal 152, as described with reference to FIG. 4.
[0135] Referring to FIG. 11, a flowchart of an aspect of a method
of high band signal generation is shown and generally designated
1100. The method 1100 may be performed by one or more components of
the systems 100-400 of FIGS. 1-4. For example, the method 1100 may
be performed by the second device 104, the HB excitation signal
generator 147 of FIG. 1, or both.
[0136] The method 1100 includes generating, at a device, a
modulated noise signal by applying spectral shaping to a first
noise signal, at 1102. For example, the HB excitation estimator 414
may generate a modulated noise signal by applying spectral shaping
to a first signal, as described with reference to FIG. 4. The first
signal may be based on the noise signal 440.
[0137] The method 1100 also includes generating, at the device, a
high-band excitation signal by combining the modulated noise signal
and a harmonically extended signal, at 1104. For example, the HB
excitation estimator 414 may generate the HB excitation signal 152
by combining the modulated noise signal and the second signal 442.
The second signal 442 may be based on the extended signal 150.
[0138] Referring to FIG. 12, a flowchart of an aspect of a method
of high band signal generation is shown and generally designated
1200. The method 1200 may be performed by one or more components of
the systems 100-400 of FIGS. 1-4. For example, the method 1200 may
be performed by the second device 104, the receiver 192, the HB
excitation signal generator 147 of FIG. 1, or a combination
thereof.
[0139] The method 1200 includes receiving, at a device, a low-band
voicing factor and a mixing configuration parameter associated with
a bandwidth-extended audio stream, at 1202. For example, the
receiver 192 may receive the LB VF 154 and the mix configuration
mode 368 associated with the audio data 126, as described with
reference to FIG. 1.
[0140] The method 1200 also includes determining, at the device, a
high-band voicing factor based on the low-band voicing factor and
the mixing configuration parameter, at 1204. For example, the HB
excitation estimator 414 may determine a HB VF based on the LB VF
154 and the mix configuration mode 368, as described with reference
to FIG. 4. In an illustrative aspect, the HB excitation estimator
414 may determine the HB VF based on application of a sigmoid
function to the LB VF 154.
[0141] The method 1200 further includes generating, at the device,
a high-band excitation signal based on the high-band mixing
configuration, at 1206. For example, the HB excitation estimator
414 may generate the HB excitation signal 152 based on the HB VF,
as described with reference to FIG. 4.
[0142] Referring to FIG. 13, a particular illustrative aspect of a
system that includes devices that are operable to generate a
high-band signal is disclosed and generally designated 1300.
[0143] The system 1300 includes the first device 102 in
communication, via the network 107, with the second device 104. The
first device 102 may include the processor 106, a memory 1332, or
both. The processor 106 may be coupled to or may include the
encoder 108, the resampler and filterbank 202, or both. The encoder
108 may include the first encoder 204 (e.g., an ACELP encoder) and
the second encoder 296 (e.g., a TBE encoder). The second encoder
296 may include the encoder bandwidth extension module 206, the
encoding module 208, or both. The encoding module 208 may include a
high-band (HB) excitation signal generator 1347, a bit-stream
parameter generator 1348, or both. The second encoder 296 may
further include a configuration module 1305, an energy normalizer
1306, or both. The resampler and filterbank 202 may be coupled to
the first encoder 204, the second encoder 296, one or more
microphones 1338, or a combination thereof.
[0144] The memory 1332 may be configured to store instructions to
perform one or more functions (e.g., the first function 164, the
second function 166, or both). The first function 164 may include a
first non-linear function (e.g., a square function) and the second
function 166 may include a second non-linear function (e.g., an
absolute value function) that is distinct from the first non-linear
function. Alternatively, such functions may be implemented using
hardware (e.g., circuitry) at the first device 102. The memory 1332
may be configured to store one or more signals (e.g., a first
excitation signal 1368, a second excitation signal 1370, or both).
The first device 102 may further include a transmitter 1392. In a
particular implementation, the transmitter 1392 may be included in
a transceiver.
[0145] During operation, the first device 102 may receive (or
generate) an input signal 114. For example, the resampler and
filterbank 202 may receive the input signal 114 via the microphones
1338. The resampler and filterbank 202 may generate the first LB
signal 240 by applying a low-pass filter to the input signal 114
and may provide the first LB signal 240 to the first encoder 204.
The resampler and filterbank 202 may generate the first HB signal
242 by applying a high-pass filter to the input signal 114 and may
provide the first HB signal 242 to the second encoder 296.
[0146] The first encoder 204 may generate the first LB excitation
signal 244 (e.g., an LB residual), the first bit-stream 128, or
both, based on the first LB signal 240. The first bit-stream 128
may include LB parameter information (e.g., LPC coefficients, LSFs,
or both). The first encoder 204 may provide the first LB excitation
signal 244 to the encoder bandwidth extension module 206. The first
encoder 204 may provide the first bit-stream 128 to the first
decoder 134 of FIG. 1. In a particular aspect, the first encoder
204 may store the first bit-stream 128 in the memory 1332. The
audio data 126 may include the first bit-stream 128.
[0147] The first encoder 204 may determine a LB voicing factor (VF)
1354 (e.g., a value from 0.0 to 1.0) based on the LB parameter
information. The LB VF 1354 may indicate a voiced/unvoiced nature
(e.g., strongly voiced, weakly voiced, weakly unvoiced, or strongly
unvoiced) of the first LB signal 240. The first encoder 204 may
provide the LB VF 1354 to the configuration module 1305. The first
encoder 204 may determine an LB pitch based on the first LB signal
240. The first encoder 204 may provide LB pitch data 1358
indicating the LB pitch to the configuration module 1305.
[0148] The configuration module 1305 may generate estimated mix
factors (e.g., mix factors 1353), a harmonicity indicator 1364
(e.g., indicating a high band coherence), a peakiness indicator
1366, the NL configuration mode 158, or a combination thereof, as
described with reference to FIG. 14. The configuration module 1305
may provide the NL configuration mode 158 to the encoder bandwidth
extension module 206. The configuration module 1305 may provide the
harmonicity indicator 1364, the mix factors 1353, or both, to the
HB excitation signal generator 1347.
[0149] The encoder bandwidth extension module 206 may generate the
first extended signal 250 based on the first LB excitation signal
244, the NL configuration mode 158, or both, as described with
reference to FIG. 17. The encoder bandwidth extension module 206
may provide the first extended signal 250 to the energy normalizer
1306. The energy normalizer 1306 may generate a second extended
signal 1350 based on the first extended signal 250, as described
with reference to FIG. 19.
[0150] The energy normalizer 1306 may provide the second extended
signal 1350 to the encoding module 208. The HB excitation signal
generator 1347 may generate an HB excitation signal 1352 based on
the second extended signal 1350, as described with reference to
FIG. 17. The bit-stream parameter generator 1348 may generate the
bit-stream parameters 160 to reduce a difference between the HB
excitation signal 1352 and the first HB signal 242. The encoding
module 208 may generate the second bit-stream 130 including the
bit-stream parameters 160, the NL configuration mode 158, or both.
The audio data 126 may include the first bit-stream 128, the second
bit-stream 130, or both. The first device 102 may transmit the
audio data 126, via the transmitter 1392, to the second device 104.
The second device 104 may generate the output signal 124 based on
the audio data 126, as described with reference to FIG. 1.
[0151] Referring to FIG. 14, a diagram of an illustrative aspect of
the configuration module 305 is depicted. The configuration module
1305 may include a peakiness estimator 1402, a LB to HB pitch
extension measure estimator 1404, a configuration mode generator
1406, or a combination thereof.
[0152] The configuration module 1305 may generate a particular HB
excitation signal (e.g., an HB residual) associated with the first
HB signal 242. The peakiness estimator 1402 may determine the
peakiness indicator 1366 based on the first HB signal 242 or the
particular HB excitation signal. The peakiness indicator 1366 may
correspond to a peak-to-average energy ratio associated with the
first HB signal 242 or the particular HB excitation signal. The
peakiness indicator 1366 may thus indicate a level of temporal
peakiness of the first HB signal 242. The peakiness estimator 1402
may provide the peakiness indicator 1366 to the configuration mode
generator 1406. The peakiness estimator 1402 may also store the
peakiness indicator 1366 in the memory 1332 of FIG. 13.
[0153] The LB to HB pitch extension measure estimator 1404 may
determine the harmonicity indicator 1364 (e.g., a LB to HB pitch
extension measure) based on the first HB signal 242 or the
particular HB excitation signal, as described with reference to
FIG. 15. The harmonicity indicator 1364 may indicate a voicing
strength of the first HB signal 242 (or the particular HB
excitation signal). The LB to HB pitch extension measure estimator
1404 may determine the harmonicity indicator 1364 based on the LB
pitch data 1358. For example, the LB to HB pitch extension measure
estimator 1404 may determine a pitch lag based on a LB pitch
indicated by the LB pitch data 1358 and may determine
auto-correlation coefficients corresponding to the first HB signal
242 (or the particular HB excitation signal) based on the pitch
lag. The harmonicity indicator 1364 may indicate a particular
(e.g., maximum) value of the auto-correlation coefficients. The
harmonicity indicator 1364 may thus be distinguished from an
indicator of tonal harmonicity. The LB to HB pitch extension
measure estimator 1404 may provide the harmonicity indicator 1364
to the configuration mode generator 1406. The LB to HB pitch
extension measure estimator 1404 may also store the harmonicity
indicator 1364 in the memory 1332 of FIG. 13.
[0154] The LB to HB pitch extension measure estimator 1404 may
determine the mix factors 1353 based on the LB VF 1354. For
example, the HB excitation estimator 414 may determine a HB VF
based on the LB VF 1354. The HB VF may correspond to a HB mixing
configuration. In a particular aspect, the LB to HB pitch extension
measure estimator 1404 determines the HB VF based on application of
a sigmoid function to the LB VF 1354. For example, the LB to HB
pitch extension measure estimator 1404 may determine the HB VF
based on Equation 7, as described with reference to FIG. 4, where
VF.sub.i may correspond to a HB VF corresponding to a sub-frame i,
and a may correspond to a normalized correlation from the LB. In a
particular aspect, at of Equation 7 may correspond to the LB VF
1354 for the sub-frame i. The LB to HB pitch extension measure
estimator 1404 may determine a first weight (e.g., HB VF) and a
second weight (e.g., 1-HB VF). The mix factors 1353 may indicate
the first weight and the second weight. The LB to HB pitch
extension measure estimator 1404 may also store the mix factors
1353 in the memory 1332 of FIG. 13.
[0155] The configuration mode generator 1406 may generate the NL
configuration mode 158 based on the peakiness indicator 1366, the
harmonicity indicator 1364, or both. For example, the configuration
mode generator 1406 may generate the NL configuration mode 158
based on the harmonicity indicator 1364, as described with
reference to FIG. 16.
[0156] In a particular implementation, the configuration mode
generator 1406 may generate the NL configuration mode 158 having a
first value (e.g., NL_HARMONIC or 0) in response to determining
that the harmonicity indicator 1364 satisfies a first threshold,
that the peakiness indicator 1366 satisfies a second threshold, or
both. The configuration mode generator 1406 may generate the NL
configuration mode 158 having a second value (e.g., NL_SMOOTH or 1)
in response to determining that the harmonicity indicator 1364
fails to satisfy the first threshold, that the peakiness indicator
1366 fails to satisfy the second threshold, or both. The
configuration mode generator 1406 may generate the NL configuration
mode 158 having a third value (e.g., NL_HYBRID or 2) in response to
determining that the harmonicity indicator 1364 fails to satisfy
the first threshold and that the peakiness indicator 1366 satisfies
the second threshold. In another aspect, the configuration mode
generator 1406 may generate the NL configuration mode 158 having
the third value (e.g., NL_HYBRID or 2) in response to determining
that the harmonicity indicator 1364 satisfies the first threshold
and that the peakiness indicator 1366 fails to satisfy the second
threshold.
[0157] In a particular implementation, the configuration module
1305 may generate the NL configuration mode 158 having the second
value (e.g., NL_SMOOTH or 1) and the mix configuration mode 368 of
FIG. 3 having a particular value (e.g., a value greater than 1) in
response to determining that the harmonicity indicator 1364 fails
to satisfy the first threshold, that the peakiness indicator 1366
fails to satisfy the second threshold, or both. The configuration
module 1305 may generate the NL configuration mode 158 having the
second value (e.g., NL_SMOOTH or 1) and the mix configuration mode
368 having another particular value (e.g., a value less than or
equal to 1) in response to determining that one of the harmonicity
indicator 1364 and the peakiness indicator 1366 satisfies a
corresponding threshold and the other of the harmonicity indicator
1364 and the peakiness indicator 1366 fails to satisfy a
corresponding threshold. The configuration mode generator 1406 may
also store the NL configuration mode 158 in the memory 1332 of FIG.
13.
[0158] Advantageously, determining the NL configuration mode 158
based on high band parameters (e.g., the peakiness indicator 1366,
the harmonicity indicator 1364, or both) may be robust to cases
where there is little (e.g., no) correlation between the first LB
signal 240 and the first HB signal 242. For example, the high-band
signal 142 may approximate the first HB signal 242 when the NL
configuration mode 158 is determined based on the high band
parameters.
[0159] Referring to FIG. 15, a diagram of an illustrative aspect of
a method of high band signal generation is shown and generally
designated 1500. The method 1500 may be performed by one or more
components of the systems 100-200, 1300-1400 of FIGS. 1-2, 13-14.
For example, the method 1500 may be performed by the first device
102, the processor 106, the encoder 108 of FIG. 1, the second
encoder 296 of FIG. 2, the configuration module 1305 of FIG. 13,
the LB to HB pitch extension measure estimator 1404 of FIG. 14, or
a combination thereof.
[0160] The method 1500 may include estimating an auto-correlation
of a HB signal at lag indices (T-L to T+L), at 1502. For example,
the configuration module 1305 of FIG. 13 may generate a particular
HB excitation signal (e.g., an HB residual signal) based on the
first HB signal 242. The LB to HB pitch extension measure estimator
1404 of FIG. 14 may generate an auto-correlation signal (e.g.,
auto-correlation coefficients 1512) based on the first HB signal
242 or the particular HB excitation signal. The LB to HB pitch
extension measure estimator 1404 may generate the auto-correlation
coefficients 1512 (R) based on lag indices within a threshold
distance (e.g., T-L to T+L) of an LB pitch (T) indicated by the LB
pitch data 1358. The auto-correlation coefficients 1512 may include
a first number (e.g., 2L) of coefficients.
[0161] The method 1500 may also include interpolating the
auto-correlation coefficients (R), at 1506. For example, the LB to
HB pitch extension measure estimator 1404 of FIG. 14 may generate
second auto-correlation coefficients 1514 (R_interp) by applying a
windowed sinc function 1504 to the auto-correlation coefficients
1512 (R). The windowed sine function 1504 may correspond to a
scaling factor (e.g., N). The second auto-correlation coefficients
1514 (R_interp) may include a second number (e.g., 2LN) of
coefficients.
[0162] The method 1500 includes estimating normalized, interpolated
auto-correlation coefficients, at 1508. For example, the LB to HB
pitch extension measure estimator 1404 may determine a second
auto-correlation signal (e.g., normalized auto-correlation
coefficients) by normalizing the second auto-correlation
coefficients 1514 (R_interp). The LB to HB pitch extension measure
estimator 1404 may determine the harmonicity indicator 1364 based
on a particular (e.g., maximum) value of the second
auto-correlation signal (e.g., the normalized auto-correlation
coefficients). The harmonicity indicator 1364 may indicate a
strength of a repetitive pitch component in the first HB signal
242. The harmonicity indicator 1364 may indicate a relative
coherence associated with the first HB signal 242. The harmonicity
indicator 1364 may indicate an LB pitch to HB pitch extension
measure.
[0163] Referring to FIG. 16, a diagram of an illustrative aspect of
a method of high band signal generation is shown and generally
designated 1600. The method 1600 may be performed by one or more
components of the systems 100-200, 1300-1400 of FIGS. 1-2, 13-14.
For example, the method 1600 may be performed by the first device
102, the processor 106, the encoder 108 of FIG. 1, the second
encoder 296 of FIG. 2, the configuration module 1305 of FIG. 13,
the configuration mode generator 1406 of FIG. 14, or a combination
thereof.
[0164] The method 1600 includes determining whether an LB to HB
pitch extension measure satisfies a threshold, at 1602. For
example, the configuration mode generator 1406 of FIG. 14 may
determine whether the harmonicity indicator 1364 (e.g., an LB to HB
pitch extension measure) satisfies a first threshold.
[0165] The method 1600 includes, in response to determining that
the LB to HB pitch extension measure satisfies the threshold, at
1602, selecting a first NL configuration mode, at 1604. For
example, the configuration mode generator 1406 of FIG. 14 may, in
response to determining that the harmonicity indicator 1364
satisfies the first threshold, generate the NL configuration mode
158 having a first value (e.g., NL_HARMONIC or 0).
[0166] Alternatively, in response to determining that the LB to HB
pitch extension measure fails to satisfy the threshold, at 1602,
the method 1600 determining whether the LB to HB pitch extension
measure fails to satisfy a second threshold, at 1606. For example,
the configuration mode generator 1406 of FIG. 14 may, in response
to determining that the harmonicity indicator 1364 fails to satisfy
the first threshold, determine whether the harmonicity indicator
1364 satisfies a second threshold.
[0167] The method 1600 includes, in response to determining that
the LB to HB pitch extension measure satisfies the second
threshold, at 1606, selecting a second NL configuration mode, at
1608. For example, the configuration mode generator 1406 of FIG. 14
may, in response to determining that the harmonicity indicator 1364
satisfies the second threshold, generate the NL configuration mode
158 having a second value (e.g., NL_SMOOTH or 1).
[0168] In response to determining that the LB to HB pitch extension
measure fails to satisfy the second threshold, at 1606, the method
1600 includes selecting a third NL configuration mode, at 1610. For
example, the configuration mode generator 1406 of FIG. 14 may, in
response to determining that the harmonicity indicator 1364 fails
to satisfy the second threshold, generate the NL configuration mode
158 having a third value (e.g., NL_HYBRID or 2).
[0169] Referring to FIG. 17, a system is disclosed and generally
designated 1700. In a particular aspect, the system 1700 may
correspond to the system 100 of FIG. 1, the system 200 of FIG. 2,
the system 1300 of FIG. 13, or a combination thereof. The system
1700 may include the encoder bandwidth extension module 206, the
energy normalizer 1306, the HB excitation signal generator 1347,
the bit-stream parameter generator 1348, or a combination thereof.
The encoder bandwidth extension module 206 may include the
resampler 402, the harmonic extension module 404, or both. The HB
excitation signal generator 1347 may include the spectral flip and
decimation module 408, the adaptive whitening module 410, the
temporal envelope modulator 412, the HB excitation estimator 414,
or a combination thereof.
[0170] During operation, the encoder bandwidth extension module 206
may generate the first extended signal 250 by extending the first
LB excitation signal 244, as described herein. The resampler 402
may receive the first LB excitation signal 244 from the first
encoder 204 of FIGS. 2 and 13. The resampler 402 may generate a
resampled signal 1706 based on the first LB excitation signal 244,
as described with reference to FIG. 5. The resampler 402 may
provide the resampled signal 1706 to the harmonic extension module
404.
[0171] The harmonic extension module 404 may generate the first
extended signal 250 (e.g., an HB excitation signal) by harmonically
extending the resampled signal 1706 in a time-domain based on the
NL configuration mode 158, as described with reference to FIG. 4.
The NL configuration mode 158 may be generated by the configuration
module 1305, as described with reference to FIG. 14. For example,
the harmonic extension module 404 may select the first function
164, the second function 166, or a hybrid function based on a value
of the NL configuration mode 158. The hybrid function may include a
combination of multiple functions (e.g., the first function 164 and
the second function 166). The harmonic extension module 404 may
generate the first extended signal 250 based on the selected
function (e.g., the first function 164, the second function 166, or
the hybrid function).
[0172] The harmonic extension module 404 may provide the first
extended signal 150 to the energy normalizer 1306. The energy
normalizer 1306 may generate the second extended signal 1350 based
on the first extended signal 250, as described with reference to
FIG. 19. The energy normalizer 1306 may provide the second extended
signal 1350 to the spectral flip and decimation module 408.
[0173] The spectral flip and decimation module 408 may generate a
spectrally flipped signal by performing spectral flipping of the
second extended signal 1350 in the time-domain, as described with
reference to FIG. 4. The spectral flip and decimation module 408
may generate a first signal 1750 (e.g., a HB excitation signal) by
decimating the spectrally flipped signal based on a first all-pass
filter and a second all-pass filter, as described with reference to
FIG. 4.
[0174] The spectral flip and decimation module 408 may provide the
first signal 1750 to the adaptive whitening module 410. The
adaptive whitening module 410 may generate a second signal 1752
(e.g., an HB excitation signal) by flattening a spectrum of the
first signal 1750 by performing fourth-order LP whitening of the
first signal 1750, as described with reference to FIG. 4. The
adaptive whitening module 410 may provide the second signal 452 to
the temporal envelope modulator 412, the HB excitation estimator
414, or both.
[0175] The temporal envelope modulator 412 may receive the second
signal 1752 from the adaptive whitening module 410, a noise signal
1740 from a random noise generator, or both. The random noise
generator may be coupled to or may be included in the first device
102. The temporal envelope modulator 412 may generate a third
signal 1754 based on the noise signal 1740, the second signal 1752,
or both. For example, the temporal envelope modulator 412 may
generate a first noise signal by applying temporal shaping to the
noise signal 1740. The temporal envelope modulator 412 may generate
a signal envelope based on the second signal 1752 (or the first LB
excitation signal 244). The temporal envelope modulator 412 may
generate the first noise signal based on the signal envelope and
the noise signal 1740. For example, the temporal envelope modulator
412 may combine the signal envelope and the noise signal 1740.
Combining the signal envelope and the noise signal 1740 may
modulate amplitude of the noise signal 1740. The temporal envelope
modulator 412 may generate the third signal 1754 by applying
spectral shaping to the first noise signal. In an alternate
implementation, the temporal envelope modulator 412 may generate
the first noise signal by applying spectral shaping to the noise
signal 1740 and may generate the third signal 1754 by applying
temporal shaping to the first noise signal. Thus, spectral and
temporal shaping may be applied in any order to the noise signal
1740. The temporal envelope modulator 412 may provide the third
signal 1754 to the HB excitation estimator 414.
[0176] The HB excitation estimator 414 may receive the second
signal 1752 from the adaptive whitening module 410, the third
signal 1754 from the temporal envelope modulator 412, the
harmonicity indicator 1364, the mix factors 1353 from the
configuration module 1305, or a combination thereof. The HB
excitation estimator 414 may generate the HB excitation signal 1352
by combining the second signal 1752 and the third signal 1754 based
on the harmonicity indicator 1364, the mix factors 1353, or
both.
[0177] The mix factors 1353 may indicate a HB VF, as described with
reference to FIG. 14. For example, the mix factors 1353 may
indicate a first weight (e.g., HB VF) and a second weight (e.g.,
1-HB VF). The HB excitation estimator 414 may adjust the mix
factors 1353 based on the harmonicity indicator 1364, as described
with reference to FIG. 18. The HB excitation estimator 414 may
power normalize the third signal 1754 so that the third signal 1754
has the same power level as the second signal 1752.
[0178] The HB excitation estimator 414 may generate the HB
excitation signal 1352 by performing a weighted sum of the second
signal 1752 and the third signal 1754 based on the adjusted mix
factors 1353, where the first weight is assigned to the second
signal 1752 and the second weight is assigned to the third signal
1754. For example, the HB excitation estimator 414 may generate
sub-frame (i) of the HB excitation signal 1352 by mixing sub-frame
(i) of the second signal 1752 that is scaled based on VF.sub.i of
Equation 7 (e.g., scaled based on a square root of VF.sub.i) and
sub-frame (i) of the third signal 1754 that is scaled based on
(1-VF.sub.i) of Equation 7 (e.g., scaled based on a square root of
(1-VF.sub.i)). The HB excitation estimator 414 may provide the HB
excitation signal 1352 to the bit-stream parameter generator
1348.
[0179] The bit-stream parameter generator 1348 may generate the
bit-stream parameters 160. For example, the bit-stream parameters
160 may include the mix configuration mode 368. The mix
configuration mode 368 may correspond to the mix factors 1353
(e.g., the adjusted mix factors 1353). As another example, the
bit-stream parameters 160 may include the NL configuration mode
158, the filter information 374, the HB LSF data 364, or a
combination thereof. The filter information 374 may include an
index generated by the energy normalizer 1306, as further described
with reference to FIG. 19. The HB LSF data 364 may correspond to a
quantized filter (e.g., quantized LSFs) generated by the energy
normalizer 1306, as further described with reference to FIG.
19.
[0180] The bit-stream parameter generator 1348 may generate target
gain information (e.g., the HB target gain data 370, the gain shape
data 372, or both) based on a comparison of the HB excitation
signal 1352 and the first HB signal 242. The bit-stream parameter
generator 1348 may update the target gain information based on the
harmonicity indicator 1364, the peakiness indicator 1366, or both.
For example, the bit-stream parameter generator 1348 may reduce an
HB gain frame indicated by the target gain information when the
harmonicity indicator 1364 indicates a strong harmonic component,
the peakiness indicator 1366 indicates a high peakiness, or both.
To illustrate, the bit-stream parameter generator 1348 may, in
response to determining that the peakiness indicator 1366 satisfies
a first threshold and the harmonicity indicator 1364 satisfies a
second threshold, reduce the HB gain frame indicated by the target
gain information.
[0181] The bit-stream parameter generator 1348 may update the
target gain information to modify a gain shape of a particular
sub-frame when the peakiness indicator 1366 indicates spikes of
energy in the first HB signal 242. The peakiness indicator 1366 may
include sub-frame peakiness values. For example, the peakiness
indicator 1366 may indicate a peakiness value of the particular
sub-frame. The sub-frame peakiness values may be "smoothed" to
determine whether the first HB signal 242 corresponds to a harmonic
HB, a non-harmonic HB, or a HB with one or more spikes. For
example, the bit-stream parameter generator 1348 may perform
smoothing by applying an approximating function (e.g., a moving
average) to the peakiness indicator 1366. Additionally, or
alternatively, the bit-stream parameter generator 1348 may update
the target gain information to modify (e.g., attenuate) a gain
shape of the particular sub-frame. The bit-stream parameters 160
may include the target gain information.
[0182] Referring to FIG. 18, a diagram of an illustrative aspect of
a method of high band signal generation is shown and generally
designated 1800. The method 1800 may be performed by one or more
components of the systems 100-200, 1300-1400 of FIGS. 1-2, 13-14.
For example, the method 1800 may be performed by the first device
102, the processor 106, the encoder 108 of FIG. 1, the second
encoder 296 of FIG. 2, the HB excitation signal generator 1347 of
FIG. 13, the LB to HB pitch extension measure estimator 1404 of
FIG. 14, or a combination thereof.
[0183] The method 1800 includes receiving a LB to HB pitch
extension measure, at 1802. For example, the HB excitation
estimator 414 may receive the harmonicity indicator 1364 (e.g., a
HB coherence value) from the configuration module 1305, as
described with reference to FIGS. 13-14 and 17.
[0184] The method 1800 also includes receiving estimated mix
factors based on low band voicing information, at 1804. For
example, the HB excitation estimator 414 may receive the mix
factors 1353 from the configuration module 1305, as described with
reference to FIGS. 13-14 and 17. The mix factors 1353 may be based
on the LB VF 1354, as described with reference to FIG. 14.
[0185] The method 1800 further includes adjusting estimated mix
factors based on knowledge of HB coherence (e.g., the LB to HB
pitch extension measure), at 1806. For example, the HB excitation
estimator 414 may adjust the mix factors 1353 based on the
harmonicity indicator 1364, as described with reference to FIG.
17.
[0186] FIG. 18 also includes a diagram of an illustrative aspect of
a method of adjusting estimated mix factors that is generally
designated 1820. The method 1820 may correspond to the step 1806 of
the method 1800.
[0187] The method 1820 includes determining whether a LB VF is
greater than a first threshold and HB coherence is less than a
second threshold, at 1808. For example, the HB excitation estimator
414 may determine whether the LB VF 1354 is greater than a first
threshold and the harmonicity indicator 1364 is less than a second
threshold. In a particular aspect, the mix factors 1353 may
indicate the LB VF 1354.
[0188] The method 1820 includes, in response to determining that
the LB VF is greater than the first threshold and that the HB
coherence is less than the second threshold, at 1808, attenuating
mix factors, at 1810. For example, the HB excitation estimator 414
may attenuate the mix factors 1353 in response to determining that
the LB VF 1354 is greater than the first threshold and that the
harmonicity indicator 1364 fails to satisfy is less than the second
threshold.
[0189] The method 1820 includes, in response to determining that
the LB VF is less than or equal to the first threshold or that the
HB coherence is greater than or equal to the second threshold, at
1808, determining whether the LB VF is less than the first
threshold and that the HB coherence is less than the second
threshold, at 1812. For example, the HB excitation estimator 414
may, in response to determining that the LB VF 1354 is less than or
equal to the first threshold or that the harmonicity indicator 1364
is greater than or equal to the second threshold, determine whether
the LB VF 1354 is less than the first threshold and that the
harmonicity indicator 1364 is greater than the second
threshold.
[0190] The method 1820 includes, in response to determining that
the LB VF is less than the first threshold and that the HB
coherence is less than the second threshold, at 1812, boosting mix
factors, at 1814. For example, the HB excitation estimator 414 may,
in response to determining that the LB VF 1354 is less than the
first threshold and that the harmonicity indicator 1364 is greater
than the second threshold, boost the mix factors 1353.
[0191] The method 1820 includes, in response to determining that
the LB VF is greater than or equal to the first threshold or that
the HB coherence is greater than or equal to the second threshold,
at 1812, leaving mix factors unchanged, at 1816. For example, the
HB excitation estimator 414 may, in response to determining that
the LB VF 1354 is greater than or equal to the first threshold or
that the harmonicity indicator 1364 is less than or equal to the
second threshold, leave the mix factors 1353 unchanged. To
illustrate, the HB excitation estimator 414 may leave the mix
factors 1353 unchanged in response to determining that the LB VF
1354 is equal to the first threshold, that the harmonicity
indicator 1364 is equal to the second threshold, that the LB VF
1354 is less than the first threshold and the harmonicity indicator
1364 is less than the second threshold, or that the LB VF 1354 is
greater than the first threshold and the harmonicity indicator 1364
is greater than the second threshold.
[0192] The HB excitation estimator 414 may adjust the mix factors
1353 based on the harmonicity indicator 1364, the LB VF 1354, or
both. The mix factors 1353 may indicate the HB VF, as described
with reference to FIG. 14. The HB excitation estimator 414 may
reduce (or increase) variations in the HB VF based on the
harmonicity indicator 1364, the LB VF 1354, or both. Modifying the
HB VF based on the harmonicity indicator 1364 and the LB VF 1354
may compensate for a mismatch between the LB VF 1354 and the HB
VF.
[0193] Lower frequencies of voiced speech signals may generally
exhibit a stronger harmonic structure than higher frequencies. An
output (e.g., the extended signal 150 of FIG. 1) of non-linear
modeling may sometimes over-emphasize harmonics in a high-band
portion and may lead to unnatural buzzy-sounding artifacts.
Attenuating the mix factors may produce a pleasant sounding
high-band signal (e.g., the high-band signal 142 of FIG. 1).
[0194] Referring to FIG. 19, a diagram of an illustrative aspect of
the energy normalizer 1306 is depicted. The energy normalizer 1306
may include a filter estimator 1902, a filter applicator 1912, or
both.
[0195] The filter estimator 1902 may include a filter adjuster
1908, an adder 1914, or both. The second encoder 296 (e.g., the
filter estimator 1902) may generate a particular HB excitation
signal (e.g., an HB residual) associated with the first HB signal
242. The filter estimator 1902 may select (or generate) a filter
1906 based on a comparison of the first extended signal 250 and the
first HB signal 242 (or the particular HB excitation signal). For
example, the filter estimator 1902 may select (or generate) the
filter 1906 to reduce (e.g., eliminate) distortion between the
first extended signal 250 and the first HB signal 242 (or the
particular HB excitation signal), as described herein. The filter
adjuster 1908 may generate a scaled signal 1916 by applying the
filter 1906 (e.g., a FIR filter) to the first extended signal 250.
The filter adjuster 1908 may provide the scaled signal 1916 to the
adder 1914. The adder 1914 may generate an error signal 1904
corresponding to a distortion (e.g., a difference) between the
scaled signal 1916 and the first HB signal 242 (or the particular
HB excitation signal). For example, the error signal 1904 may
correspond to a mean-squared error between the scaled signal 1916
and the first HB signal 242 (or the particular HB excitation
signal). The adder 1914 may generate the error signal 1904 based on
a least mean squares (LMS) algorithm. The adder 1914 may provide
the error signal 1904 to the filter adjuster 1908.
[0196] The filter adjuster 1908 may select (e.g., adjust) the
filter 1906 based on the error signal 1904. For example, the filter
adjuster 1908 may iteratively adjust the filter 1906 to reduce a
distortion metric (e.g., a mean-squared error metric) between a
first harmonic component of the scaled signal 1916 and a second
harmonic component of the first HB signal 242 (or the particular HB
excitation signal) by reducing (or eliminating) an energy of the
error signal 1904. The filter adjuster 1908 may generate the scaled
signal 1916 by applying the adjusted filter 1906 to the first
extended signal 250. The filter estimator 1902 may provide the
filter 1906 (e.g., the adjusted filter 1906) to the filter
applicator 1912.
[0197] The filter applicator 1912 may include a quantizer 1918, a
FIR filter engine 1924, or both. The quantizer 1918 may generate a
quantized filter 1922 based on the filter 1906. For example, the
quantizer 1918 may generate filter coefficients (e.g., LSP
coefficients, or LPCs) corresponding to the filter 1906. The
quantizer 1918 may generate quantized filter coefficients by
performing a multi-stage (e.g., 2-stage) vector quantization (VQ)
on the filter coefficients. The quantized filter 1922 may include
the quantized filter coefficients. The quantizer 1918 may provide a
quantization index 1920 corresponding to the quantized filter 1922
to the bit-stream parameter generator 1348 of FIG. 13. The
bit-stream parameters 160 may include the filter information 374
indicating the quantization index 1920, the HB LSF data 364
corresponding to the quantized filter 1922 (e.g., the quantized LSP
coefficients or the quantized LPCs), or both.
[0198] The quantizer 1918 may provide the quantized filter 1922 to
the FIR filter engine 1924. The FIR filter engine 1924 may generate
the second extended signal 1350 by filtering the first extended
signal 250 based on the quantized filter 1922. The FIR filter
engine 1924 may provide the second extended signal 1350 to the HB
excitation signal generator 1347 of FIG. 13.
[0199] Referring to FIG. 20, a diagram of an aspect of a method of
high band signal generation is shown and generally designated 2000.
The method 2000 may be performed by one or more components of the
systems 100, 200, or 1300 of FIG. 1, 2 or 13. For example, the
method 2000 may be performed by the first device 102, the processor
106, the encoder 108 of FIG. 1, the second encoder 296 of FIG. 2,
the energy normalizer 1306 of FIG. 13, the filter estimator 1902,
the filter applicator 1912 of FIG. 19, or a combination
thereof.
[0200] The method 2000 includes receiving a high band signal and a
first extended signal, at 2002. For example, the energy normalizer
1306 of FIG. 13 may receive the first HB signal 242 and the first
extended signal 250, as described with reference to FIG. 13.
[0201] The method 2000 also includes estimating a filter (h(n))
which minimizes (or reduces) energy of error, at 2004. For example,
the filter estimator 1902 of FIG. 19 may estimate the filter 1906
to reduce an energy of the error signal 1904, as described with
reference to FIG. 19.
[0202] The method 2000 further includes quantizing and transmitting
an index corresponding to h(n), at 2006. For example, the quantizer
1918 may generate the quantized filter 1922 by quantizing the
filter 1906, as described with reference to FIG. 19. The quantizer
1918 may generate the quantization index 1920 corresponding to the
filter 1906, as described with reference to FIG. 19.
[0203] The method 2000 also includes using the quantized filter and
filtering the first extended signal to generate a second extended
signal, at 2008. For example, the FIR filter engine 1924 may
generate the second extended signal 1350 by filtering the first
extended signal 250 based on the quantized filter 1922.
[0204] Referring to FIG. 21, a flowchart of an aspect of a method
of high band signal generation is shown and generally designated
2100. The method 2100 may be performed by one or more components of
the systems 100, 200, or 1300 of FIG. 1, 2 or 13. For example, the
method 2100 may be performed by the first device 102, the processor
106, the encoder 108 of FIG. 1, the first encoder 204, the second
encoder 296 of FIG. 2, the bit-stream parameter generator 1348, the
transmitter 1392 of FIG. 13, or a combination thereof.
[0205] The method 2100 includes receiving an audio signal at a
first device, at 2102. For example, the encoder 108 of the second
device 104 may receive the input signal 114, as described with
reference to FIG. 13.
[0206] The method 2100 also includes generating, at the first
device, a signal modeling parameter based on a harmonicity
indicator, a peakiness indicator, or both, the signal modeling
parameter associated with a high-band portion of the audio signal,
at 2104. For example, the encoder 108 of the second device 104 may
generate the NL configuration mode 158, the mix configuration mode
368, target gain information (e.g., the HB target gain data 370,
the gain shape data 372, or both), or a combination thereof, as
described with reference to FIGS. 13, 14, 16, and 17. To
illustrate, the configuration mode generator 1406 may generate the
NL configuration mode 158, as described with reference to FIGS. 14
and 16. The HB excitation estimator 414 may generate the mix
configuration mode 368 based on the mix factors 1353, the
harmonicity indicator 1364, or both, as described with reference to
FIG. 17. The bit-stream parameter generator 1348 may generate the
target gain information, as described with reference to FIG.
17.
[0207] The method 2100 further includes sending, from the first
device to a second device, the signal modeling parameter in
conjunction with a bandwidth-extended audio stream corresponding to
the audio signal, at 2106. For example, the transmitter 1392 of
FIG. 13 may transmit, from the second device 104 to the first
device 102, the NL configuration mode 158, the mix configuration
mode 368, the HB target gain data 370, the gain shape data 372, or
a combination thereof, in conjunction with the audio data 126.
[0208] Referring to FIG. 22, a flowchart of an aspect of a method
of high band signal generation is shown and generally designated
2200. The method 2200 may be performed by one or more components of
the systems 100, 200, or 1300 of FIG. 1, 2 or 13. For example, the
method 2200 may be performed by the first device 102, the processor
106, the encoder 108 of FIG. 1, the first encoder 204, the second
encoder 296 of FIG. 2, the bit-stream parameter generator 1348, the
transmitter 1392 of FIG. 13, or a combination thereof.
[0209] The method 2200 includes receiving an audio signal at a
first device, at 2202. For example, the encoder 108 of the second
device 104 may receive the input signal 114 (e.g., an audio
signal), as described with reference to FIG. 13.
[0210] The method 2200 also includes generating, at the first
device, a high-band excitation signal based on a high-band portion
of the audio signal, at 2204. For example, the resampler and
filterbank 202 of the second device 104 may generate the first HB
signal 242 based on a high-band portion of the input signal 114, as
described with reference to FIG. 13. The second encoder 296 may
generate a particular HB excitation signal (e.g., an HB residual)
based on the first HB signal 242.
[0211] The method 2200 further includes generating, at the first
device, a modeled high-band excitation signal based on a low-band
portion of the audio signal, at 2206. For example, the encoder
bandwidth extension module 206 of the second device 104 may
generate the first extended signal 250 based on the first LB signal
240, as described with reference to FIG. 13. The first LB signal
240 may correspond to a low-band portion of the input signal
114.
[0212] The method 2200 also includes selecting, at the first
device, a filter based on a comparison of the modeled high-band
excitation signal and the high-band excitation signal, at 2208. For
example, the filter estimator 1902 of the second device 104 may
select the filter 1906 based on a comparison of the first extended
signal 250 and the first HB signal 242 (or the particular HB
excitation signal), as described with reference to FIG. 19.
[0213] The method 2200 further includes sending, from the first
device to a second device, filter information corresponding to the
filter in conjunction with a bandwidth-extended audio stream
corresponding to the audio signal, at 2210. For example, the
transmitter 1392 may transmit, from the second device 104 to the
first device 102, the filter information 374, the HB LSF data 364,
or both, in conjunction with the audio data 126 corresponding to
the input signal 114, as described with reference to FIGS. 13 and
19.
[0214] Referring to FIG. 23, a flowchart of an aspect of a method
of high band signal generation is shown and generally designated
2300. The method 2300 may be performed by one or more components of
the systems 100, 200, or 1300 of FIG. 1, 2 or 13. For example, the
method 2300 may be performed by the first device 102, the processor
106, the encoder 108 of FIG. 1, the first encoder 204, the second
encoder 296 of FIG. 2, the bit-stream parameter generator 1348, the
transmitter 1392 of FIG. 13, or a combination thereof.
[0215] The method 2300 includes receiving an audio signal at a
first device, at 2302. For example, the encoder 108 of the second
device 104 may receive the input signal 114 (e.g., an audio
signal), as described with reference to FIG. 13.
[0216] The method 2300 also includes generating, at the first
device, a high-band excitation signal based on a high-band portion
of the audio signal, at 2304. For example, the resampler and
filterbank 202 of the second device 104 may generate the first HB
signal 242 based on a high-band portion of the input signal 114, as
described with reference to FIG. 13. The second encoder 296 may
generate a particular HB excitation signal (e.g., an HB residual)
based on the first HB signal 242.
[0217] The method 2300 further includes generating, at the first
device, a modeled high-band excitation signal based on a low-band
portion of the audio signal, at 2306. For example, the encoder
bandwidth extension module 206 of the second device 104 may
generate the first extended signal 250 based on the first LB signal
240, as described with reference to FIG. 13. The first LB signal
240 may correspond to a low-band portion of the input signal
114.
[0218] The method 2300 also includes generating, at the first
device, filter coefficients based on a comparison of the modeled
high-band excitation signal and the high-band excitation signal, at
2308. For example, the filter estimator 1902 of the second device
104 may generate filter coefficients corresponding to the filter
1906 based on a comparison of the first extended signal 250 and the
first HB signal 242 (or the particular HB excitation signal), as
described with reference to FIG. 19.
[0219] The method 2300 further includes generating, at the first
device, filter information by quantizing the filter coefficients,
at 2310. For example, the quantizer 1918 of the second device 104
may generate the quantization index 1920 and the quantized filter
1922 (e.g., quantized filter coefficients) by quantizing the filter
coefficients corresponding to the filter 1906, as described with
reference to FIG. 19. The quantizer 1918 may generate the filter
information 374 indicating the quantization index 1920, the HB LSF
data 364 indicating the quantized filter coefficients, or both.
[0220] The method 2300 also includes sending, from the first device
to a second device, the filter information in conjunction with a
bandwidth-extended audio stream corresponding to the audio signal,
at 2210. For example, the transmitter 1392 may transmit, from the
second device 104 to the first device 102, the filter information
374, the HB LSF data 364, or both, in conjunction with the audio
data 126 corresponding to the input signal 114, as described with
reference to FIGS. 13 and 19.
[0221] Referring to FIG. 24, a flowchart of an aspect of a method
of high band signal generation is shown and generally designated
2400. The method 2400 may be performed by one or more components of
the systems 100, 200, or 1300 of FIG. 1, 2 or 13. For example, the
method 2400 may be performed by the first device 102, the processor
106, the encoder 108, the second device 104, the processor 116, the
decoder 118, the second decoder 136, the decoding module 162, the
HB excitation signal generator 147 of FIG. 1, the second encoder
296, the encoding module 208, the encoder bandwidth extension
module 206 of FIG. 2, the system 400, the harmonic extension module
404 of FIG. 4, or a combination thereof.
[0222] The method 2400 includes selecting, at a device, a plurality
of non-linear processing functions based at least in part on a
value of a parameter, at 2402. For example, the harmonic extension
module 404 may select the first function 164 and the second
function 166 of FIG. 1 based at least in part on a value of the NL
configuration mode 158, as described with reference to FIGS. 4 and
17.
[0223] The method 2400 also includes generating, at the device, a
high-band excitation signal based on the plurality of non-linear
processing functions, at 2404. For example, the harmonic extension
module 404 may generate the extended signal 150 based on the first
function 164 and the second function 166, as described with
reference to FIG. 4. As another example, the harmonic extension
module 404 may generate the first extended signal 250 based on the
first function 164 and the second function 166, as described with
reference to FIG. 17.
[0224] The method 2400 may thus enable selection of a plurality of
non-linear functions based on a value of a parameter. A high-band
excitation signal may be generated, at an encoder, a decoder, or
both, based on the plurality of non-linear functions.
[0225] Referring to FIG. 25, a flowchart of an aspect of a method
of high band signal generation is shown and generally designated
2500. The method 2500 may be performed by one or more components of
the systems 100, 200, or 1300 of FIG. 1, 2 or 13. For example, the
method 2500 may be performed by the second device 104, the receiver
192, the HB excitation signal generator 147, the decoding module
162, the second decoder 136, the decoder 118, the processor 116 of
FIG. 1, or a combination thereof.
[0226] The method 2500 includes receiving, at a device, a parameter
associated with a bandwidth-extended audio stream, at 2502. For
example, the receiver 192 may receive the HR configuration mode 366
associated with the audio data 126, as described with reference to
FIGS. 1 and 3.
[0227] The method 2500 also includes determining, at the device, a
value of the parameter, at 2504. For example, the synthesis module
418 may determine a value of the HR configuration mode 366, as
described with reference to FIG. 4.
[0228] The method 2500 further includes selecting, based on the
value of the parameter, one of target gain information associated
with the bandwidth-extended audio stream or filter information
associated with the bandwidth-extended audio stream, at 2506. For
example, when the value of the HR configuration mode 366 is 1, the
synthesis module 418 may select target gain information, such as
one or more of the gain shape data 372, the HB target gain data
370, or the gain information 362, as described with reference to
FIG. 4. When the value of the HR configuration mode 366 is 0, the
synthesis module 418 may select the filter information 374, as
described with reference to FIG. 4.
[0229] The method 2500 also includes generating, at the device, a
high-band excitation signal based on the one of the target gain
information or the filter information, at 2508. For example, the
synthesis module 418 may generate a modified excitation signal
based on the selected one of the target gain information or the
filter information 374, as described with reference to FIG. 4.
[0230] The method 2500 may thus enable selection of target gain
information or filter information based on a value of a parameter.
A high-band excitation signal may be generated, at a decoder, based
on the selected one of the target gain information or the filter
information.
[0231] Referring to FIG. 26, a block diagram of a particular
illustrative aspect of a device (e.g., a wireless communication
device) is depicted and generally designated 2600. In various
aspects, the device 2600 may have fewer or more components than
illustrated in FIG. 26. In an illustrative aspect, the device 2600
may correspond to the first device 102 or the second device 104 of
FIG. 1. In an illustrative aspect, the device 2600 may perform one
or more operations described with reference to systems and methods
of FIGS. 1-25.
[0232] In a particular aspect, the device 2600 includes a processor
2606 (e.g., a central processing unit (CPU)). The device 2600 may
include one or more additional processors 2610 (e.g., one or more
digital signal processors (DSPs)). The processors 2610 may include
a media (e.g., speech and music) coder-decoder (CODEC) 2608, and an
echo canceller 2612. The media CODEC 2608 may include the decoder
118, the encoder 108, or both. The decoder 118 may include the
first decoder 134, the second decoder 136, the signal generator
138, or a combination thereof. The second decoder 136 may include
the TBE frame converter 156, the bandwidth extension module 146,
the decoding module 162, or a combination thereof. The decoding
module 162 may include the HB excitation signal generator 147, the
HB signal generator 148, or both. The encoder 108 may include the
first encoder 204, the second encoder 296, the resampler and
filterbank 202, or a combination thereof. The second encoder 296
may include the energy normalizer 1306, the encoding module 208,
the encoder bandwidth extension module 206, the configuration
module 1305, or a combination thereof. The encoding module 208 may
include the HB excitation signal generator 1347, the bit-stream
parameter generator 1348, or both.
[0233] Although the media CODEC 2608 is illustrated as a component
of the processors 2610 (e.g., dedicated circuitry and/or executable
programming code), in other aspects one or more components of the
media CODEC 2608, such as the decoder 118, the encoder 108, or
both, may be included in the processor 2606, the CODEC 2634,
another processing component, or a combination thereof.
[0234] The device 2600 may include a memory 2632 and a CODEC 2634.
The memory 2632 may correspond to the memory 132 of FIG. 1, the
memory 1332 of FIG. 13, or both. The device 2600 may include a
transceiver 2650 coupled to an antenna 2642. The transceiver 2650
may include the receiver 192 of FIG. 1, the transmitter 1392 of
FIG. 13, or both. The device 2600 may include a display 2628
coupled to a display controller 2626. One or more speakers 2636,
one or more microphones 2638, or a combination thereof, may be
coupled to the CODEC 2634. In a particular aspect, the speakers
2636 may correspond to the speakers 122 of FIG. 1. The microphones
2638 may correspond to the microphones 1338 of FIG. 13. The CODEC
2634 may include a digital-to-analog converter (DAC) 2602 and an
analog-to-digital converter (ADC) 2604.
[0235] The memory 2632 may include instructions 2660 executable by
the processor 2606, the processors 2610, the CODEC 2634, another
processing unit of the device 2600, or a combination thereof, to
perform one or more operations described with reference to FIGS.
1-25.
[0236] One or more components of the device 2600 may be implemented
via dedicated hardware (e.g., circuitry), by a processor executing
instructions to perform one or more tasks, or a combination
thereof. As an example, the memory 2632 or one or more components
of the processor 2606, the processors 2610, and/or the CODEC 2634
may be a memory device, such as a random access memory (RAM),
magnetoresistive random access memory (MRAM), spin-torque transfer
MRAM (STT-MRAM), flash memory, read-only memory (ROM), programmable
read-only memory (PROM), erasable programmable read-only memory
(EPROM), electrically erasable programmable read-only memory
(EEPROM), registers, hard disk, a removable disk, or a compact disc
read-only memory (CD-ROM). The memory device may include
instructions (e.g., the instructions 2660) that, when executed by a
computer (e.g., a processor in the CODEC 2634, the processor 2606,
and/or the processors 2610), may cause the computer to perform one
or more operations described with reference to FIGS. 1-25. As an
example, the memory 2632 or the one or more components of the
processor 2606, the processors 2610, the CODEC 2634 may be a
non-transitory computer-readable medium that includes instructions
(e.g., the instructions 2660) that, when executed by a computer
(e.g., a processor in the CODEC 2634, the processor 2606, and/or
the processors 2610), cause the computer perform one or more
operations described with reference to FIGS. 1-25.
[0237] In a particular aspect, the device 2600 may be included in a
system-in-package or system-on-chip device (e.g., a mobile station
modem (MSM)) 2622. In a particular aspect, the processor 2606, the
processors 2610, the display controller 2626, the memory 2632, the
CODEC 2634, and the transceiver 2650 are included in a
system-in-package or the system-on-chip device 2622. In a
particular aspect, an input device 2630, such as a touchscreen
and/or keypad, and a power supply 2644 are coupled to the
system-on-chip device 2622. Moreover, in a particular aspect, as
illustrated in FIG. 26, the display 2628, the input device 2630,
the speakers 2636, the microphones 2638, the antenna 2642, and the
power supply 2644 are external to the system-on-chip device 2622.
However, each of the display 2628, the input device 2630, the
speakers 2636, the microphones 2638, the antenna 2642, and the
power supply 2644 can be coupled to a component of the
system-on-chip device 2622, such as an interface or a
controller.
[0238] The device 2600 may include a wireless telephone a mobile
communication device, a smart phone, a cellular phone, a laptop
computer, a desktop computer, a computer, a tablet computer, a set
top box, a personal digital assistant, a display device, a
television, a gaming console, a music player, a radio, a video
player, an entertainment unit, a communication device, a fixed
location data unit, a personal media player, a digital video
player, a digital video disc (DVD) player, a tuner, a camera, a
navigation device, a decoder system, an encoder system, a media
playback device, a media broadcast device, or any combination
thereof.
[0239] In a particular aspect, one or more components of the
systems described with reference to FIGS. 1-25 and the device 2600
may be integrated into a decoding system or apparatus (e.g., an
electronic device, a CODEC, or a processor therein), into an
encoding system or apparatus, or both. In other aspects, one or
more components of the systems described with reference to FIGS.
1-25 and the device 2600 may be integrated into a wireless
telephone, a tablet computer, a desktop computer, a laptop
computer, a set top box, a music player, a video player, an
entertainment unit, a television, a game console, a navigation
device, a communications device, a personal digital assistant
(PDA), a fixed location data unit, a personal media player, or
another type of device.
[0240] It should be noted that various functions performed by the
one or more components of the systems described with reference to
FIGS. 1-25 and the device 2600 are described as being performed by
certain components or modules. This division of components and
modules is for illustration only. In an alternate aspect, a
function performed by a particular component or module may be
divided amongst multiple components or modules. Moreover, in an
alternate aspect, two or more components or modules described with
reference to FIGS. 1-26 may be integrated into a single component
or module. Each component or module illustrated in FIGS. 1-26 may
be implemented using hardware (e.g., a field-programmable gate
array (FPGA) device, an application-specific integrated circuit
(ASIC), a DSP, a controller, etc.), software (e.g., instructions
executable by a processor), or any combination thereof.
[0241] In conjunction with the described aspects, an apparatus is
disclosed that includes means for storing a parameter associated
with a bandwidth-extended audio stream. For example, the means for
storing may include the second device 104, memory 132 of FIG. 1,
the media storage 292 of FIG. 2, the memory 2632 of FIG. 25, one or
more devices configured to store a parameter, or a combination
thereof.
[0242] The apparatus also includes means for generating a high-band
excitation signal based on a plurality of non-linear processing
functions. For example, the means for generating may include the
first device 102, the processor 106, the encoder 108, the second
device 104, the processor 116, the decoder 118, the second decoder
136, the decoding module 162 of FIG. 1, the second encoder 296, the
encoding module 208, the encoder bandwidth extension module 206 of
FIG. 2, the system 400, the harmonic extension module 404 of FIG.
4, the processors 2610, the media codec 2608, the device 2600 of
FIG. 25, one or more devices configured to generate a high-band
excitation signal based on a plurality of non-linear processing
functions (e.g., a processor executing instructions stored at a
computer-readable storage device), or a combination thereof. The
plurality of non-linear processing functions may be selected based
at least in part on a value of the parameter.
[0243] Also, in conjunction with the described aspects, an
apparatus is disclosed that includes means for receiving a
parameter associated with a bandwidth-extended audio stream. For
example, the means for receiving may include the receiver 192 of
FIG. 1, the transceiver 2695 of FIG. 25, one or more devices
configured to receive a parameter associated with a
bandwidth-extended audio stream, or a combination thereof.
[0244] The apparatus also includes means for generating a high-band
excitation signal based on one of target gain information
associated with the bandwidth-extended audio stream or filter
information associated with the bandwidth-extended audio stream.
For example, the means for generating may include the HB excitation
signal generator 147, the decoding module 162, the second decoder
136, the decoder 118, the processor 116, the second device 104 of
FIG. 1, the synthesis module 418 of FIG. 4, the processors 2610,
the media codec 2608, the device 2600 of FIG. 25, one or more
devices configured to generate a high-band excitation signal, or a
combination thereof. The one of the target gain information or the
filter information may be selected based on a value of the
parameter.
[0245] Further, in conjunction with the described aspects, an
apparatus is disclosed that includes means for generating a signal
modeling parameter based on a harmonicity indicator, a peakiness
indicator, or both. For example, the means for generating may
include the first device 102, the processor 106, the encoder 108 of
FIG. 1, the second encoder 296, the encoding module 208 of FIG. 2,
the configuration module 1305, the energy normalizer 1306, the
bit-stream parameter generator 1348 of FIG. 13, one or more devices
configured to generate a signal modeling parameter based on the
harmonicity indicator, the peakiness indicator, or both (e.g., a
processor executing instructions stored at a computer-readable
storage device), or a combination thereof. The signal modeling
parameter may be associated with a high-band portion of an audio
signal.
[0246] The apparatus also includes means for transmitting the
signal modeling parameter in conjunction with a bandwidth-extended
audio stream corresponding to the audio signal. For example, the
means for transmitting may include the transmitter 1392 of FIG. 13,
the transceiver 2695 of FIG. 25, one or more devices configured to
transmit the signal modeling parameter, or a combination
thereof.
[0247] Also, in conjunction with the described aspects, an
apparatus is disclosed that includes means for selecting a filter
based on a comparison of a modeled high-band excitation signal and
a high-band excitation signal. For example, the means for selecting
may include the first device 102, the processor 106, the encoder
108 of FIG. 1, the second encoder 296, the encoding module 208 of
FIG. 2, the energy normalizer 1306 of FIG. 13, the filter estimator
1902 of FIG. 19, one or more devices configured to select the
filter (e.g., a processor executing instructions stored at a
computer-readable storage device), or a combination thereof. The
high-band excitation signal may be based on a high-band portion of
an audio signal. The modeled high-band excitation signal may be
based on a low-band portion of the audio signal.
[0248] The apparatus also includes means for transmitting filter
information corresponding to the filter in conjunction with a
bandwidth-extended audio stream corresponding to the audio signal.
For example, the means for transmitting may include the transmitter
1392 of FIG. 13, the transceiver 2695 of FIG. 25, one or more
devices configured to transmit the signal modeling parameter, or a
combination thereof.
[0249] Further, in conjunction with the described aspects, an
apparatus includes means for quantizing filter coefficients that
are generated based on a comparison of a modeled high-band
excitation signal and a high-band excitation signal. For example,
the means for quantizing filter coefficients may include the first
device 102, the processor 106, the encoder 108 of FIG. 1, the
second encoder 296, the encoding module 208 of FIG. 2, the energy
normalizer 1306 of FIG. 13, the filter applicator 1912, the
quantizer 1918 of FIG. 19, one or more devices configured to
quantize filter coefficients (e.g., a processor executing
instructions stored at a computer-readable storage device), or a
combination thereof. The high-band excitation signal may be based
on a high-band portion of an audio signal. The modeled high-band
excitation signal may be based on a low-band portion of the audio
signal.
[0250] The apparatus also includes means for transmitting filter
information in conjunction with a bandwidth-extended audio stream
corresponding to the audio signal. For example, the means for
transmitting may include the transmitter 1392 of FIG. 13, the
transceiver 2695 of FIG. 25, one or more devices configured to
transmit the signal modeling parameter, or a combination thereof.
The filter information may be based on the quantized filter
coefficients.
[0251] Referring to FIG. 27, a block diagram of a particular
illustrative example of a base station 2700 is depicted. In various
implementations, the base station 2700 may have more components or
fewer components than illustrated in FIG. 27. In an illustrative
example, the base station 2700 may include the first device 102,
the second device 104 of FIG. 1, or both. In an illustrative
example, the base station 2700 may perform one or more operations
described with reference to FIGS. 1-26.
[0252] The base station 2700 may be part of a wireless
communication system. The wireless communication system may include
multiple base stations and multiple wireless devices. The wireless
communication system may be a Long Term Evolution (LTE) system, a
Code Division Multiple Access (CDMA) system, a Global System for
Mobile Communications (GSM) system, a wireless local area network
(WLAN) system, or some other wireless system. A CDMA system may
implement Wideband CDMA (WCDMA), CDMA 1.times., Evolution-Data
Optimized (EVDO), Time Division Synchronous CDMA (TD-SCDMA), or
some other version of CDMA.
[0253] The wireless devices may also be referred to as user
equipment (UE), a mobile station, a terminal, an access terminal, a
subscriber unit, a station, etc. The wireless devices may include a
cellular phone, a smartphone, a tablet, a wireless modem, a
personal digital assistant (PDA), a handheld device, a laptop
computer, a smartbook, a netbook, a tablet, a cordless phone, a
wireless local loop (WLL) station, a Bluetooth device, etc. The
wireless devices may include or correspond to the device 2600 of
FIG. 26.
[0254] Various functions may be performed by one or more components
of the base station 2700 (and/or in other components not shown),
such as sending and receiving messages and data (e.g., audio data).
In a particular example, the base station 2700 includes a processor
2706 (e.g., a CPU). The processor 2706 may correspond to the
processor 106, the processor 116 of FIG. 1, or both. The base
station 2700 may include a transcoder 2710. The transcoder 2710 may
include an audio CODEC 2708. For example, the transcoder 2710 may
include one or more components (e.g., circuitry) configured to
perform operations of the audio CODEC 2708. As another example, the
transcoder 2710 may be configured to execute one or more
computer-readable instructions to perform the operations of the
audio CODEC 2708. Although the audio CODEC 2708 is illustrated as a
component of the transcoder 2710, in other examples one or more
components of the audio CODEC 2708 may be included in the processor
2706, another processing component, or a combination thereof. For
example, a vocoder decoder 2738 may be included in a receiver data
processor 2764. As another example, a vocoder encoder 2736 may be
included in a transmission data processor 2766.
[0255] The transcoder 2710 may function to transcode messages and
data between two or more networks. The transcoder 2710 may be
configured to convert message and audio data from a first format
(e.g., a digital format) to a second format. To illustrate, the
vocoder decoder 2738 may decode encoded signals having a first
format and the vocoder encoder 2736 may encode the decoded signals
into encoded signals having a second format. Additionally or
alternatively, the transcoder 2710 may be configured to perform
data rate adaptation. For example, the transcoder 2710 may
downconvert a data rate or upconvert the data rate without changing
a format the audio data. To illustrate, the transcoder 2710 may
downconvert 64 kbit/s signals into 16 kbit/s signals.
[0256] The audio CODEC 2708 may include the vocoder encoder 2736
and the vocoder decoder 2738. The vocoder encoder 2736 may include
an encoder selector, a speech encoder, and a non-speech encoder.
The vocoder encoder 2736 may include the encoder 108. The vocoder
decoder 2738 may include a decoder selector, a speech decoder, and
a non-speech decoder. The vocoder decoder 2738 may include the
decoder 118.
[0257] The base station 2700 may include a memory 2732. The memory
2732, such as a computer-readable storage device, may include
instructions. The instructions may include one or more instructions
that are executable by the processor 2706, the transcoder 2710, or
a combination thereof, to perform one or more operations described
with reference to FIGS. 1-26. The base station 2700 may include
multiple transmitters and receivers (e.g., transceivers), such as a
first transceiver 2752 and a second transceiver 2754, coupled to an
array of antennas. The array of antennas may include a first
antenna 2742 and a second antenna 2744. The array of antennas may
be configured to wirelessly communicate with one or more wireless
devices, such as the device 2600 of FIG. 26. For example, the
second antenna 2744 may receive a data stream 2714 (e.g., a bit
stream) from a wireless device. The data stream 2714 may include
messages, data (e.g., encoded speech data), or a combination
thereof.
[0258] The base station 2700 may include a network connection 2760,
such as backhaul connection. The network connection 2760 may be
configured to communicate with a core network or one or more base
stations of the wireless communication network. For example, the
base station 2700 may receive a second data stream (e.g., messages
or audio data) from a core network via the network connection 2760.
The base station 2700 may process the second data stream to
generate messages or audio data and provide the messages or the
audio data to one or more wireless device via one or more antennas
of the array of antennas or to another base station via the network
connection 2760. In a particular implementation, the network
connection 2760 may be a wide area network (WAN) connection, as an
illustrative, non-limiting example.
[0259] The base station 2700 may include a demodulator 2762 that is
coupled to the transceivers 2752, 2754, the receiver data processor
2764, and the processor 2706, and the receiver data processor 2764
may be coupled to the processor 2706. The demodulator 2762 may be
configured to demodulate modulated signals received from the
transceivers 2752, 2754 and to provide demodulated data to the
receiver data processor 2764. The receiver data processor 2764 may
be configured to extract a message or audio data from the
demodulated data and send the message or the audio data to the
processor 2706.
[0260] The base station 2700 may include a transmission data
processor 2766 and a transmission multiple input-multiple output
(MIMO) processor 2768. The transmission data processor 2766 may be
coupled to the processor 2706 and the transmission MIMO processor
2768. The transmission MIMO processor 2768 may be coupled to the
transceivers 2752, 2754 and the processor 2706. The transmission
data processor 2766 may be configured to receive the messages or
the audio data from the processor 2706 and to code the messages or
the audio data based on a coding scheme, such as CDMA or orthogonal
frequency-division multiplexing (OFDM), as an illustrative,
non-limiting examples. The transmission data processor 2766 may
provide the coded data to the transmission MIMO processor 2768.
[0261] The coded data may be multiplexed with other data, such as
pilot data, using CDMA or OFDM techniques to generate multiplexed
data. The multiplexed data may then be modulated (i.e., symbol
mapped) by the transmission data processor 2766 based on a
particular modulation scheme (e.g., Binary phase-shift keying
("BPSK"), Quadrature phase-shift keying ("QSPK"), M-ary phase-shift
keying ("M-PSK"), M-ary Quadrature amplitude modulation ("M-QAM"),
etc.) to generate modulation symbols. In a particular
implementation, the coded data and other data may be modulated
using different modulation schemes. The data rate, coding, and
modulation for each data stream may be determined by instructions
executed by processor 2706.
[0262] The transmission MIMO processor 2768 may be configured to
receive the modulation symbols from the transmission data processor
2766 and may further process the modulation symbols and may perform
beamforming on the data. For example, the transmission MIMO
processor 2768 may apply beamforming weights to the modulation
symbols. The beamforming weights may correspond to one or more
antennas of the array of antennas from which the modulation symbols
are transmitted.
[0263] During operation, the second antenna 2744 of the base
station 2700 may receive a data stream 2714. The second transceiver
2754 may receive the data stream 2714 from the second antenna 2744
and may provide the data stream 2714 to the demodulator 2762. The
demodulator 2762 may demodulate modulated signals of the data
stream 2714 and provide demodulated data to the receiver data
processor 2764. The receiver data processor 2764 may extract audio
data from the demodulated data and provide the extracted audio data
to the processor 2706. In a particular aspect, the data stream 2714
may correspond to the audio data 126.
[0264] The processor 2706 may provide the audio data to the
transcoder 2710 for transcoding. The vocoder decoder 2738 of the
transcoder 2710 may decode the audio data from a first format into
decoded audio data and the vocoder encoder 2736 may encode the
decoded audio data into a second format. In some implementations,
the vocoder encoder 2736 may encode the audio data using a higher
data rate (e.g., upconvert) or a lower data rate (e.g.,
downconvert) than received from the wireless device. In other
implementations the audio data may not be transcoded. Although
transcoding (e.g., decoding and encoding) is illustrated as being
performed by a transcoder 2710, the transcoding operations (e.g.,
decoding and encoding) may be performed by multiple components of
the base station 2700. For example, decoding may be performed by
the receiver data processor 2764 and encoding may be performed by
the transmission data processor 2766.
[0265] The vocoder decoder 2738 and the vocoder encoder 2736 may
select a corresponding decoder (e.g., a speech decoder or a
non-speech decoder) and a corresponding encoder to transcode (e.g.,
decode and encode) the frame. Encoded audio data generated at the
vocoder encoder 2736, such as transcoded data, may be provided to
the transmission data processor 2766 or the network connection 2760
via the processor 2706.
[0266] The transcoded audio data from the transcoder 2710 may be
provided to the transmission data processor 2766 for coding
according to a modulation scheme, such as OFDM, to generate the
modulation symbols. The transmission data processor 2766 may
provide the modulation symbols to the transmission MIMO processor
2768 for further processing and beamforming. The transmission MIMO
processor 2768 may apply beamforming weights and may provide the
modulation symbols to one or more antennas of the array of
antennas, such as the first antenna 2742 via the first transceiver
2752. Thus, the base station 2700 may provide a transcoded data
stream 2716, that corresponds to the data stream 2714 received from
the wireless device, to another wireless device. The transcoded
data stream 2716 may have a different encoding format, data rate,
or both, than the data stream 2714. In other implementations, the
transcoded data stream 2716 may be provided to the network
connection 2760 for transmission to another base station or a core
network.
[0267] The base station 2700 may therefore include a
computer-readable storage device (e.g., the memory 2732) storing
instructions that, when executed by a processor (e.g., the
processor 2706 or the transcoder 2710), cause the processor to
perform operations including selecting a plurality of non-linear
processing functions based at least in part on a value of a
parameter. The parameter is associated with a bandwidth-extended
audio stream. The operations also include generating a high-band
excitation signal based on the plurality of non-linear processing
functions.
[0268] In a particular aspect, the base station 2700 may include a
computer-readable storage device (e.g., the memory 2732) storing
instructions that, when executed by a processor (e.g., the
processor 2706 or the transcoder 2710), cause the processor to
perform operations including receiving a parameter associated with
a bandwidth-extended audio stream. The operations also include
determining a value of the parameter. The operations further
include selecting, based on the value of the parameter, one of
target gain information associated with the bandwidth-extended
audio stream or filter information associated with the
bandwidth-extended audio stream. The operations also include
generating a high-band excitation signal based on the one of the
target gain information or the filter information.
[0269] Those of skill would further appreciate that the various
illustrative logical blocks, configurations, modules, circuits, and
algorithm steps described in connection with the aspects disclosed
herein may be implemented as electronic hardware, computer software
executed by a processing device such as a hardware processor, or
combinations of both. Various illustrative components, blocks,
configurations, modules, circuits, and steps have been described
above generally in terms of their functionality. Whether such
functionality is implemented as hardware or executable software
depends upon the particular application and design constraints
imposed on the overall system. Skilled artisans may implement the
described functionality in varying ways for each particular
application, but such implementation decisions should not be
interpreted as causing a departure from the scope of the present
disclosure.
[0270] The steps of a method or algorithm described in connection
with the aspects disclosed herein may be embodied directly in
hardware, in a software module executed by a processor, or in a
combination of the two. A software module may reside in a memory
device, such as random access memory (RAM), magnetoresistive random
access memory (MRAM), spin-torque transfer MRAM (STT-MRAM), flash
memory, read-only memory (ROM), programmable read-only memory
(PROM), erasable programmable read-only memory (EPROM),
electrically erasable programmable read-only memory (EEPROM),
registers, hard disk, a removable disk, or a compact disc read-only
memory (CD-ROM). An exemplary memory device is coupled to the
processor such that the processor can read information from, and
write information to, the memory device. In the alternative, the
memory device may be integral to the processor. The processor and
the storage medium may reside in an application-specific integrated
circuit (ASIC). The ASIC may reside in a computing device or a user
terminal. In the alternative, the processor and the storage medium
may reside as discrete components in a computing device or a user
terminal.
[0271] The previous description of the disclosed aspects is
provided to enable a person skilled in the art to make or use the
disclosed aspects. Various modifications to these aspects will be
readily apparent to those skilled in the art, and the principles
defined herein may be applied to other aspects without departing
from the scope of the disclosure. Thus, the present disclosure is
not intended to be limited to the aspects shown herein but is to be
accorded the widest scope possible consistent with the principles
and novel features as defined by the following claims.
* * * * *