U.S. patent application number 10/047282 was filed with the patent office on 2002-08-22 for transmission system.
Invention is credited to Ibaraki, Susumu, Mori, Toshiaki, Yamamoto, Akihiro.
Application Number | 20020114359 10/047282 |
Document ID | / |
Family ID | 18873667 |
Filed Date | 2002-08-22 |
United States Patent
Application |
20020114359 |
Kind Code |
A1 |
Ibaraki, Susumu ; et
al. |
August 22, 2002 |
Transmission system
Abstract
The present invention provide a transmission system comprising a
transmission apparatus for transmitting audio data of multi
channels and auxiliary data required for playback of the audio
data, and a receiving apparatus for receiving the audio data and
the auxiliary data which are transmitted by the transmission
apparatus. A multiplexer of the transmission apparatus creates
block data that is composed of 8 frames, and first 1 byte of each
frame is allocated to a header having Sync, OE and the like, the
second byte is allocated to the auxiliary data including AUX data
and copyright protect information, and remaining bytes are used to
transmit the audio data. An encryptor carries out an encryption
process for the second and later bytes of each frame, and a
communication means outputs encrypted data. A communication means
of the receiving apparatus receives the encrypted data from the
transmission apparatus, a decoder decodes the encrypted data, and a
demultiplexer demultiplexes the audio data and the auxiliary data.
Therefore, this transmission system transmits multi-channel audio
data of the DVD-Audio or the like efficiently on a transmission
line using fixed length frames according to the MOST method, and
takes measures for copyright protection of audio data.
Inventors: |
Ibaraki, Susumu; (Osaka,
JP) ; Yamamoto, Akihiro; (Osaka, JP) ; Mori,
Toshiaki; (Osaka, JP) |
Correspondence
Address: |
WALL MARJAMA & BILINSKI
101 SOUTH SALINA STREET
SUITE 400
SYRACUSE
NY
13202
US
|
Family ID: |
18873667 |
Appl. No.: |
10/047282 |
Filed: |
January 14, 2002 |
Current U.S.
Class: |
370/535 ;
370/260; G9B/20.002; G9B/20.014 |
Current CPC
Class: |
G11B 20/10527 20130101;
G11B 20/00086 20130101; G11B 20/00818 20130101; H04H 20/88
20130101; G11B 20/00507 20130101; G11B 20/0021 20130101; G11B
20/00181 20130101; G11B 20/00775 20130101; G11B 20/00746
20130101 |
Class at
Publication: |
370/535 ;
370/260 |
International
Class: |
H04J 003/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 12, 2001 |
JP |
2001-005640 |
Claims
What is claimed is:
1. A transmission system comprising: a transmission apparatus for
transmitting audio data of multi channels and auxiliary data
required for playback of the audio data; and a receiving apparatus
for receiving the audio data and the auxiliary data which are
transmitted by the transmission apparatus, wherein the auxiliary
data include channel assignment information of the audio data.
2. The transmission system of claim 1 wherein the auxiliary data
further includes sampling frequency information.
3. The transmission system of claim 1 wherein the auxiliary data
further includes quantization bit information.
4. The transmission system of claim 1 wherein the channel
assignment information of the audio data is based on DVD-Audio
standards.
5. The transmission system of claim 1 wherein the transmission
apparatus comprises a multiplexer for multiplexing the audio data
and the auxiliary data, to create multiplexed data, and the
receiving apparatus comprises a demultiplexer for receiving the
multiplexed data transmitted from the transmission apparatus, and
demultiplexing the data into audio data and auxiliary data.
6. The transmission system of claim 1 wherein when transmitting
audio data having various sampling frequencies to the receiving
apparatus, the transmission apparatus multiplexes and transmits
first-generated audio data first.
7. The transmission system of claim 1 wherein according to a method
for transmitting the audio data and the auxiliary data, the data
are time divided into transmission frames, and as for transmission
of the audio data, prescribed bits are assigned to each
transmission frame.
8. The transmission system of claim 1 wherein a method for
transmitting the audio data and the auxiliary data complies with a
MOST method.
9. A transmission system comprising a transmission apparatus for
transmitting digital data and auxiliary data required for playback
of the digital data; and a receiving apparatus for receiving the
digital data and the auxiliary data which are transmitted from the
transmission apparatus, wherein the transmission apparatus
comprises: a multiplexer for multiplexing the digital data and the
auxiliary data, to create block data which is composed of n frames
as a multiple of a predetermined encryption unit; and an encryptor
for encrypting the block data in the predetermined encryption unit,
to create encrypted data, and the receiving apparatus comprises: a
decoder for decoding the encrypted data transmitted from the
transmission apparatus; and a demultiplexer for demultiplexing the
block data decoded by the decoder into digital data and auxiliary
data.
10. The transmission system of claim 9 wherein the predetermined
encryption unit is 8 bytes.
11. The transmission system of claim 9 wherein the multiplexer
multiplexes copyright protect information as information for
protecting copyright concerning the digital data, in plural frames
within the block data.
12. The transmission system of claim 11 wherein the copyright
protection information includes at least copy permission
information indicating whether copying of the digital data is
permitted or not, in a first one of the frames in which the
information is multiplexed.
13. The transmission system of claim 11 wherein the copyright
protect information includes copy permission information indicating
whether copying of the digital data is permitted or not, copy times
information indicating how many times of copying is permitted when
the copying is permitted, copy quality information indicating the
quality of copying when the copying is permitted, and audio
transaction information indicating whether special audio access
control is performed or not.
14. The transmission system of claim 9 wherein according to a
method for transmitting the digital data and the auxiliary data,
the data are time divided into transmission frames, and as for
transmission of the digital data and the auxiliary data, prescribed
bits are assigned to each transmission frame.
15. The transmission system of claim 9 wherein a method for
transmitting the digital data and the auxiliary data complies with
a MOST method.
16. A transmission apparatus which receives audio data and
copyright protect information that is information for protecting
copyright of the audio data, and generates a periodic signal with
eight transmission frames as one cycle, comprising: a first
multiplexer means for multiplexing the copyright protect
information in synchronization with the periodic signal; an
encryptor means for performing encryption in synchronization with
the periodic signal; and a second multiplexer means for
multiplexing periodic information indicating information of the
periodic signal in synchronization with the periodic signal.
17. The transmission apparatus of claim 16 wherein a method for
transmitting the data complies with a MOST method.
18. A receiving apparatus which receives audio data and copyright
protect information, from a transmission apparatus which receives
the audio data and the copyright protect information that is
information for protecting copyright of the audio data and
generates a periodic signal with eight transmission frames as one
cycle, comprising: a first demultiplexer means for generating a
periodic signal on the basis of periodic information as information
of the periodic signal detected from the received data; a decoder
means for performing decoding in synchronization with the periodic
signal; and a second demultiplexer means for demultiplexing the
copyright protect information in synchronization with the periodic
signal.
19. The receiving apparatus of claim 18 wherein a method for
transmitting the data complies with a MOST method.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a transmission system for
transmitting real time data, typified by digital audio data.
BACKGROUND OF THE INVENTION
[0002] As an example of methods for transmitting data recorded on a
conventional compact disc (CD) or the like, there is a method
called MOST (Media Oriented Synchronous Transfer). (Reference:
Patrick Heck et al., "Media Oriented Synchronous Transfer--A
Network Protocol for High Quality, Low Cost Transfer of
Synchronous, Asynchronous, and Control Data on Fiber Optics",
Presented AES 103rd, September 1997, Preprint 4551.)
[0003] Hereinafter, the conventional data transmission method
according to the MOST method will be described with reference to
FIGS. 11 and 12.
[0004] FIGS. 11(a) and 11(b) are diagrams illustrating a data
structure of a frame included in data to be transmitted.
[0005] As shown in FIG. 11(a), according to the conventional
transmission method, data are transmitted in frames, which are
transmitted at 44.1 kHz, i.e., once every 22.67 msec. The data
length of one frame is 512 bits. As shown in FIG. 11(b), the frame
is composed of a preamble 501, a boundary descriptor 502, a
synchronous channel area 503, an asynchronous channel area 504, a
control frame 505, a frame control data 506 and a parity 507. Here,
the cycle of the frame is not limited to 44.1 kHz but it may be 48
kHz.
[0006] Here, the preamble 501, the boundary descriptor 502 and the
synchronous channel area 503 in the frame are described, while the
asynchronous channel area 504, the control frame 505, the frame
control data 506 and the parity 507 will not be described here
because they are not directly associated with the present
invention.
[0007] The preamble 501 is 4-bit data having a determined pattern,
which is used by a transmission apparatus and a receiving apparatus
performing transmission to detect boundaries of frames. The
boundary descriptor 502 is 4-bit data, which indicates how many
pieces of 4-byte block data constitutes the synchronous channel
area 503 and is used to show the boundary between the synchronous
channel area 503 and the asynchronous channel area 504.
[0008] The synchronous channel area 503 is data having the length
of 0-480 bits, which length is decided by the boundary descriptor
502. The synchronous channel area 503 is used for transmission of
real time data such as audio. Here, the real time data is data each
having time restriction and transmission of the real time data
requires that the transmission delay time should be definable.
[0009] The data constituting the synchronous channel area 503 are
allocated to the transmission apparatus and the receiving apparatus
in byte units as time slots. That is, the data constituting the
synchronous channel area 503 can use maximum 60 time slots as the
synchronous channel area. The time slots which are to be used for
transmission are previously allocated to the transmission apparatus
and the receiving apparatus, and a group of time slots used for one
transmission is defined as a logical channel. The transmission
apparatus transmits data using the allocated time slots, and the
receiving apparatus receives data of the allocated time slots.
Using one time slot in the MOST method corresponds to transmission
of data at a transmission rate of 352.8 kbps. To be more specific,
data of a compact disk (CD) having a transmission rate of 1.4112
Mbps can be transmitted by using 4 time slots of the synchronous
channel area 503.
[0010] FIG. 12 is a diagram for explaining a method for
transmitting digital audio data using the conventional synchronous
channel.
[0011] In this figure, contents of time slots in respective frames
1 and 2 which are used by L and R channels for transmitting digital
audio data are shown. 16-bit audio samples 1 and 3 in the frames 1
and 2 are transmitted by the L channel and 16-bit audio samples 2
and 4 are transmitted by the R channel, respectively.
[0012] According to the conventional transmission method, a method
for transmitting 2-channel audio data which are recorded on a CD or
the like is determined, while a data transmission method for
transmitting multi-channel audio data which are recorded on a
DVD-Video or a DVD-Audio, or audio data having a higher sampling
frequency or a longer quantization word length is not determined
and thus the multi-channel data cannot be transmitted.
[0013] In addition, according to the conventional transmission
method, when data are encrypted for copyright protection typified
by DTCP (Digital Transmission Content Protection Specification),
there are following two problems. The first one is that when
commonly used encryption in 8-byte units is performed in the
transmission apparatus, data of each frame according to the
conventional transmission method is not always a multiple of 8
bytes and thus the encryption is not completed within the frame.
The second problem is that although copyright protect information
is supposed to be transmitted according to the DTCP, its
transmission method is not determined in the conventional
transmission method.
SUMMARY OF THE INVENTION
[0014] The present invention has for its object to provide a
transmission system which can transmit multi-channel audio data in
a DVD-Audio or the like efficiently on a transmission line using a
fixed length frame according to the MOST method or the like, and
implement copyright protection of audio data.
[0015] Other objects and advantages of the present invention will
become apparent from the detailed description and specific
embodiments described are provided only for illustration since
various additions and modifications within the spirit and scope of
the invention will be apparent to those of skill in the art from
the detailed description.
[0016] According to a 1st aspect of the present invention, there is
provided a transmission system comprising: a transmission apparatus
for transmitting audio data of multi channels and auxiliary data
required for playback of the audio data; and a receiving apparatus
for receiving the audio data and the auxiliary data which are
transmitted by the transmission apparatus, in which the auxiliary
data include channel assignment information of the audio data.
[0017] According to a 2nd aspect of the present invention, in the
transmission system of the 1st aspect, the auxiliary data further
includes sampling frequency information.
[0018] According to a 3rd aspect of the present invention, in the
transmission system of the 1st aspect, the auxiliary data further
includes quantization bit information.
[0019] According to a 4th aspect of the present invention, in the
transmission system of the 1st aspect, the channel assignment
information of the audio data is based on DVD-Audio standards.
[0020] According to a 5th aspect of the present invention, in the
transmission system of the 1st aspect, the transmission apparatus
comprises a multiplexer for multiplexing the audio data and the
auxiliary data to create multiplexed data, and the receiving
apparatus comprises a demultiplexer for receiving the multiplexed
data transmitted from the transmission apparatus, and
demultiplexing the data into audio data and auxiliary data.
[0021] According to a 6th aspect of the present invention, in the
transmission system of the 1st aspect, when transmitting audio data
having various sampling frequencies to the receiving apparatus, the
transmission apparatus multiplexes and transmits first-generated
audio data first.
[0022] According to a 7th aspect of the present invention, in the
transmission system of the 1st aspect, according to a method for
transmitting the audio data and the auxiliary data, the data are
time divided into transmission frames, and as for transmission of
the audio data, prescribed bits are assigned to each transmission
frame.
[0023] According to an 8th aspect of the present invention, in the
transmission system of the 1st aspect, a method for transmitting
the audio data and the auxiliary data complies with a MOST
method.
[0024] According to a 9th aspect of the present invention, there is
provided a transmission system comprising a transmission apparatus
for transmitting digital data and auxiliary data required for
playback of the digital data; and a receiving apparatus for
receiving the digital data and the auxiliary data which are
transmitted from the transmission apparatus, in which the
transmission apparatus comprises: a multiplexer for multiplexing
the digital data and the auxiliary data to create block data which
is composed of n frames as a multiple of a predetermined encryption
unit; and an encryptor for encrypting the block data in the
predetermined encryption unit to create encrypted data, and the
receiving apparatus comprises: a decoder for decoding the encrypted
data transmitted from the transmission apparatus; and a
demultiplexer for demultiplexing the block data decoded by the
decoder into digital data and auxiliary data.
[0025] According to a 10th aspect of the present invention, in the
transmission system of the 9th aspect, the predetermined encryption
unit is 8 bytes.
[0026] According to an 11th aspect of the present invention, in the
transmission system of the 9th aspect, the multiplexer multiplexes
copyright protect information as information for protecting
copyright concerning the digital data, in plural frames within the
block data.
[0027] According to a 12th aspect of the present invention, in the
transmission system of the 11th aspect, the copyright protection
information includes at least copy permission information
indicating whether copying of the digital data is permitted or not,
in a first one of the frames in which the information is
multiplexed.
[0028] According to a 13th aspect of the present invention, in the
transmission system of the 11th aspect, the copyright protect
information includes copy permission information indicating whether
copying of the digital data is permitted or not, copy times
information indicating how many times of copying is permitted when
the copying is permitted, copy quality information indicating the
quality of copying when the copying is permitted, and audio
transaction information indicating whether special audio access
control is performed or not.
[0029] According to a 14th aspect of the present invention, in the
transmission system of the 9th aspect, according to a method for
transmitting the digital data and the auxiliary data, the data are
time divided into transmission frames, and as for transmission of
the digital data and the auxiliary data, prescribed bits are
assigned to each transmission frame.
[0030] According to a 15th aspect of the present invention, in the
transmission system of the 9th aspect, a method for transmitting
the digital data and the auxiliary data complies with a MOST
method.
[0031] According to a 16th aspect of the present invention, there
is provided a transmission apparatus which receives audio data and
copyright protect information that is information for protecting
copyright of the audio data, and generates a periodic signal with
eight transmission frames as one cycle, comprising: a first
multiplexer means for multiplexing the copyright protect
information in synchronization with the periodic signal; an
encryptor means for performing encryption in synchronization with
the periodic signal; and a second multiplexer means for
multiplexing periodic information indicating information of the
periodic signal in synchronization with the periodic signal.
[0032] According to a 17th aspect of the present invention, in the
transmission apparatus of the 16th aspect, a method for
transmitting the data complies with a MOST method.
[0033] According to an 18th aspect of the present invention, there
is provided a receiving apparatus which receives audio data and
copyright protect information, from a transmission apparatus which
receives the audio data and the copyright protect information that
is information for protecting copyright of the audio data and
generates a periodic signal with eight transmission frames as one
cycle, comprising: a first demultiplexer means for generating a
periodic signal on the basis of periodic information as information
of the periodic signal detected from the received data; a decoder
means for performing decoding in synchronization with the periodic
signal; and a second demultiplexer means for demultiplexing the
copyright protect information in synchronization with the periodic
signal.
[0034] According to a 19th aspect of the present invention, in the
receiving apparatus of the 18th aspect, a method for transmitting
the data complies with a MOST method.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] FIG. 1 is a block diagram illustrating a structure of a
transmission system according to a first embodiment of the present
invention.
[0036] FIG. 2 is a diagram for explaining block data which are
transmitted by the transmission system of the first embodiment.
[0037] FIG. 3 is a diagram for explaining copyright protect
information included in the block data of FIG. 2.
[0038] FIG. 4 is a diagram for explaining AUX data included in the
block data of FIG. 2.
[0039] FIG. 5 is a diagram for explaining channel assignment
information in the AUX data of FIG. 4.
[0040] FIG. 6 is a diagram for explaining a data transmission
method by the transmission system of the first embodiment.
[0041] FIGS. 7(a) to 7(c) are diagrams for explaining structures of
audio samples at respective quantization word lengths.
[0042] FIG. 8 is a diagram for explaining a method for transmitting
data that is composed of frames of various cycles.
[0043] FIG. 9 is a block diagram illustrating a structure of
another transmission system which is different from that shown in
FIG. 1.
[0044] FIG. 10 is a diagram illustrating another example of block
data transmitted by the transmission system of the first
embodiment.
[0045] FIGS. 11(a) and 11(b) are diagrams for illustrating a data
structure of a frame included in data to be transmitted.
[0046] FIG. 12 is a diagram for explaining a data transmission
method according to a conventional transmission system.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiment 1
[0047] Hereinafter, an embodiment of the present invention will be
described with reference to FIGS. 1 to 10.
[0048] FIG. 1 is a block diagram illustrating a structure of a
transmission system according to the present invention.
[0049] In FIG. 1, reference numeral 21 denotes a digital audio
output apparatus, numeral 22 denotes a transmission apparatus,
numeral 23 denotes a receiving apparatus, and numeral 24 denotes a
digital audio playback apparatus. Numeral 51 denotes a multiplexer
means. Numeral 52 denotes an encryptor means. Numeral 53 denotes a
communication means. Numeral 61 denotes a communication means.
Numeral 62 denotes a decoder means. Numeral 63 denotes a
demultiplexer means.
[0050] The digital audio output apparatus 21 is an apparatus for
outputting digital audio data, typified by a drive of a DVD-Audio,
and it outputs digital audio data and related auxiliary data which
are recorded on a disc.
[0051] The multiplexer means 51 multiplexes the audio data and the
auxiliary data which are outputted by the digital audio output
apparatus 21, and outputs multiplexed data. The encryptor means 52
carries out an encryption process in predetermined data units (this
data unit is defined as an encryption unit) according to the
conventional encryption method and, when the encryption unit is 8
bytes, encrypts digital data as an encryption target every 8
bytes.
[0052] The communication means 53 receives the data encrypted by
the encryptor means 52, and transmits the encrypted data to the
communication means 61 on the receiving apparatus 23 side. The
communication means 61 receives the signal transmitted by the
communication means 53 on the transmission apparatus 22 side, and
outputs the signal to the decoder means 62. The communication means
53 and the communication means 61 transmit the data using the
synchronous channel area according to the MOST method as described
in the prior art.
[0053] The decoder means 62 receives the data outputted from the
communication means 61, and carries out a decoding process in
encryption units (=8 bytes). When a synchronization between the
transmission apparatus 22 and the receiving apparatus 23 cannot be
obtained, and when the data of the encryption unit at the
encryption and the data of the encryption unit at the decoding
deviate from each other or when part of the data of the encryption
unit lacks, the encrypted data cannot be decoded by the decoder
means 62 correctly. That is, the decoder means 62 should insure the
correct synchronization of the data of the encryption unit selected
by the encryptor means 52 and recognize the data. The demultiplexer
means 63 receives the data outputted from the decoder means 62,
demultiplexes the data into audio data and auxiliary data, and
outputs the demultiplexed data.
[0054] The digital audio playback apparatus 24 is typically an
apparatus that is constituted by a digital amplifier and a speaker,
and it receives the audio data and the auxiliary data outputted
from the receiving apparatus 23, plays back the audio data, and
outputs audible audio.
[0055] FIG. 2 is a diagram for explaining block data to be
transmitted from the transmission apparatus 22 to the receiving
apparatus 23 according to the first embodiment.
[0056] As shown in FIG. 2, one block is composed of 8 frames, i.e.,
frames 1 to 8, and in each of the frames 1 to 8, the 1st byte is a
header 101, the 2nd byte is auxiliary data 102, and "n" bytes from
the 3rd byte is audio data 103. Each of the frames 1 to 8
corresponds to a frame of a prescribed cycle (a frame every 44.1
kHz or 48 kHz in the MOST method) on a transmission line. Each of
the frames 1 to 8 include data of time slots which are used by the
communication means 53 of the transmission apparatus 22 for
transmission of data.
[0057] Here, the time slots used by the communication means 53 are
reserved before data transmission, and information indicating which
time slot is to be used is shared by the communication means 53 and
the communication means 61. Further, for the time slots used by the
communication means 53, 2 bytes composed of the header 101 and the
auxiliary data 102, as well as the audio data 103 are reserved. For
example, when the audio data 103 transmitted by the respective
frames 1 to 8 is 30 bytes, 32-byte time slots are reserved.
[0058] The frames 1 and 2 in the block data are sync bits, each
frame entirely indicating a synchronous pattern. The 2nd and 3rd
bits of the frame 3 are an EMI (Encryption Mode Indicator) and the
4th bit is an OE (Odd/Even), and the EMI and the OE are bits
defined in the DTCP. The above-mentioned sync, EMI and OE are
multiplexed in a non-encrypted area 120 that is not encrypted. The
sync is data used for finding the head of the block data, and the
length or pattern of the sync is not limited to that shown here but
it may be arbitrarily set.
[0059] The auxiliary data 102 includes copyright protect
information indicating a copyright holder of the audio data 103 or
whether copying of the audio data is permitted or not, and AUX data
(auxiliary information) required for playback of the audio data,
such as the sampling frequency, quantization word length and
channel assignment information of the audio data 103.
[0060] In FIG. 2, it is assumed as an example that the 2nd bytes of
the frames 1 to 3 are copyright protect information and the 2nd
bytes of the frames 4 to 8 are AUX data, while of course arbitrary
data can be transmitted using eight bytes.
[0061] The copyright protect information of the DVD-Audio is
described in "DVD Specifications for Read-Only Part4. Audio
Specification Version 1.2". The copyright protect information is
composed of 3-byte data, and consists of copy permission
information (audio_copy_permission), information of times of
copying (audio_copy_number), copy quality information
(audio_quality), audio transaction information (audio_transaction),
ISRC status information (ISRC_Status), ISRC number information
(UPC_EAN_ISRC_number), and ISRC data information
(UPC_EAN_ISRC_data).
[0062] FIG. 3 shows an example of arrangement of respective
information of the copyright protect information.
[0063] Copyright protect information 1 is copy control information,
and it consists of 2-bit copy permission information, 3-bit copying
times information, 2-bit copy quality information, and 1-bit audio
transaction information.
[0064] The copy permission information is information indicating
whether copying is permitted or not. To be more specific, "00"
indicates that copying is permitted, "10" indicates that copying is
permitted by the number of times indicated by the copying times
information, and "11" indicates that copying is not permitted.
[0065] The copying times information is information indicating how
many times of copying is permitted when the copying is permitted.
"000" indicates copying is permitted once, "001" indicates twice,
"010" indicates 4 times, "011" indicates 6 times, "100" indicates 8
times, "101" indicates 10 times, and "111" indicates that the
number of times of copying is unlimited.
[0066] The copy quality information is information indicating the
audio quality of copying when the copying is permitted. "00"
indicates that the number of channels is two or less, the sampling
frequency is 48 kHz or less, and the quantization word length is 16
bits or less. "01" indicates that the number of channels is two or
less and there is no restriction on the sampling frequency or the
quantization word length. "10" indicates that there is no
restriction on the number of channels, the sampling frequency, or
the quantization word length.
[0067] The audio transaction information is a flag indicating
whether specific audio access control is performed or not. "0"
indicates that no access control is performed and "1" indicates
that the access control is not reserved for the future in the
present circumstances.
[0068] Copyright protect information 2 is ISRC information (music
information), and consists of 3-bit ISRC status information and
5-bit ISRC number information. Copyright protect information 3 is
ISRC information and consists of 8-bit ISRC data information.
[0069] The ISRC status information is status information of an
ISRC, which is used to find a position at which the ISRC
information is changed. "001" indicates the start position of
music, "010" indicates an intermediate position, i.e., indicates
that there is no change in the ISRC information, and "100"
indicates the end position.
[0070] The ISRC number information indicates a number for
identifying the music.
[0071] It is desirable that the copy permission information, the
copying times information, the copy quality information, and the
audio transaction information be multiplexed at an earlier position
in the auxiliary data 102. Thereby, it is possible to decide
earlier how to process the audio information on the receiving
end.
[0072] The arrangement of the respective information may be an
arbitrary arrangement as long as it is decided between the
transmission apparatus and the receiving apparatus. Further, the
copyright protect information is not limited to the above-mentioned
type but arbitrary information decided in a recording medium or a
broadcasting system can be employed.
[0073] Next, an example of the AUX data arrangement is shown in
FIG. 4.
[0074] AUX 1 consists of a quantization word length 1 of 4 bits and
a quantization word length 2 of 4 bits. The quantization word
length 1 is data indicating the quantization word length of Channel
group 1 and the quantization word length 2 is data indicating the
quantization word length of Channel group 2, and "0" indicates 16
bits, "1" indicates 20 bits, and "3" indicates 24 bits,
respectively. AUX 2 consists of a sampling frequency 1 of 4 bits
and a sampling frequency 2 of 4 bits. The sampling frequency 1 is
data indicating the sampling frequency of Channel group 1 and the
sampling frequency 2 is data indicating the sampling frequency of
Channel group 2, and "0" indicates 48 kHz, "1" indicates 96 kHz,
"2" indicates 192 kHz, "4" indicates 44.1 kHz, "5" indicates 88.2
kHz, and "6" indicates 176 kHz, respectively. Further, AUX 3
consists of channel assignment information of 5 bits and a reserved
area of 3 bits. The channel assignment information indicates
channel assignment of multi-channel audio data 103.
[0075] FIG. 5 is a diagram for explaining the channel assignment
information of multi-channel audio data in the DVD-Audio.
(Reference: "Standardization of DVD-Audio" by Shinbo et al. in
Matsushita Technical Journal Vol. 45, No. 6, December 1999 ) FIG. 6
is a diagram for explaining a digital audio data transmission
method utilizing a synchronous channel.
[0076] In FIG. 5, C denotes a center channel, L and R denote left
and right channels, Lf and Rf denote left and right front channels,
Ls and Rs denote left and right rear channels or surround channels,
Lfe denotes a low frequency effects channel, and S denotes a
surround channel, respectively.
[0077] As shown in FIG. 5, the value of the channel assignment
information can specify multi-channel audio data which is
transmitted to each of channels CH1 to CH6, and the channel group 1
or 2 to which each data belongs.
[0078] The audio data 103 in the block data is transmitted
according to the value of the channel assignment information, with
the respective audio samples of channels CH1 to CHn being arranged
successively as shown in FIG. 6. Here, the value of "n" depends on
the value of the channel assignment information. Further, the
respective audio data 103 of CHx consists of "m" audio samples
depending on the value of the sampling frequency of its channel
group. For example, when the frequency band of the transmission
line is 48 kHz, the audio data 103 belongs to the channel group 1,
and the sampling frequency 1 is 96 kHz, the audio data consists of
two audio samples. When the sampling frequency is 192 kHz, the
audio data consists of four audio samples. The number of bits X of
each audio sample corresponds to the quantization word length of
the channel group of each audio sample.
[0079] FIGS. 7(a) to 7(c) are diagrams for explaining structures of
audio samples at respective quantization word lengths.
[0080] Initially, it is assumed that an audio sample is mapped
successively from a higher byte (x-th byte) to a lower byte
((x+n)-th byte). For example, in the case of an audio sample of
16-bit quantization word length as shown in FIG. 7(a), 8 bits are
mapped to the x-th higher byte (Hi byte) and 8 bits are mapped to
the (x+1)-th lower byte (Lo byte), whereby the audio sample is
transmitted using the time slot of 2 bytes in total.
[0081] In the case of an audio sample of 20-bit quantization word
length as shown in FIG. 7(b), 8 bits are mapped to the x-th Hi
byte, 8 bits are mapped to the (x+1)-th middle byte (Mid byte), 4
bits are mapped to the (x+2)-th Lo byte, and remaining 4 bits are
reserved in an empty state. Thus, in the case of the 20-bit audio
sample, the audio sample is transmitted using the time slot of 3
bytes in total.
[0082] In the case of an audio sample of 24-bit quantization word
length as shown in FIG. 7(c), 8 bits are mapped to the x-th Hi
byte, 8 bits are mapped to the (x+1)-th Mid byte, and 8 bits are
mapped to the (x+2) Lo byte, whereby the audio sample is
transmitted using the time slot of 3 bytes in total.
[0083] As described above, the audio samples of respective
quantization word lengths can be transmitted from an MSB (Most
Significant Bit) first successively in the following order: Hi
byte, Mid byte, and Lo byte. However, the transmission order is not
limited to this but the data may be transmitted from a LSB (Least
significant Bit) first successively in the reverse order. Further,
the audio sample may be mapped to any bit positions within the
constituting bytes. In FIG. 7(b), excess bits in the (x+2)-th byte
are made blank, while the blank can be eliminated by mapping two of
20-bit samples to 5 bytes.
[0084] FIG. 8 is a diagram for explaining a method for transmitting
data that is composed of frames of various cycles. In FIG. 8, the
abscissa represents time when audio samples of each cycle (48 kHz,
96 kHz, 192 kHz) are transmitted.
[0085] According to the MOST method, when the sampling frequency of
data to be transmitted is 48 kHz, one audio sample (A1) is
transmitted per one frame. When the sampling frequency is 96 kHz,
two audio samples (B1, B2) are transmitted per one frame. When the
sampling frequency is 192 kHz, four audio samples (C1, C2, C3, C4)
are transmitted per one frame.
[0086] For example, when the audio sample of 48-kHz sampling
frequency, the audio sample of 96 kHz sampling frequency and the
audio sample of 192 kHz sampling frequency are mixed and
transmitted, the normalization is performed such that the audio
sample of each channel is located at the top position in the frame
and the audio samples are transmitted successively from
earlier-generated audio samples. To be more specific, in the
above-mentioned example, the audio samples A1, B1 and C1 are
transmitted at the first transmission, the audio sample C2 is
transmitted at the second transmission, the audio samples B2 and C3
are transmitted at the third transmission, and the audio sample C4
is transmitted at the fourth transmission.
[0087] Next, another transmission system will be described with
reference to FIG. 9.
[0088] In FIG. 9, numeral 71 denotes a digital audio output
apparatus, numeral 72 denotes a transmission apparatus, numeral 73
denotes a receiving apparatus, and numeral 74 denotes a digital
audio playback apparatus. Numeral 80 denotes an encryption unit.
Numeral 81 denotes a first multiplexer means. Numeral 82 denotes an
encryptor means. Numeral 83 denotes a second multiplexer means.
Numeral 84 denotes a control means. Numeral 85 denotes a
communication means. Numeral 90 denotes a decoding unit. Numeral 91
denotes a communication means. Numeral 92 denotes a first
demultiplexer means. Numeral 93 denotes a decoder means. Numeral 94
denotes a second demultiplexer means. Numeral 95 denotes a control
means.
[0089] The digital audio output apparatus 71 receives a clock
outputted by the communication means 85 and outputs audio data as
well as outputs copyright protect information and auxiliary
information concerning audio as auxiliary data, in synchronization
with the clock.
[0090] The first multiplexer means 81 receives the audio data, the
auxiliary information and the copyright protect information
outputted from the digital audio output apparatus 71, multiplexes
these data, and outputs multiplexed data. The encryptor means 82
receives the multiplexed data from the first multiplexer means 81,
encrypts areas of audio data 103 and auxiliary data 102 on the
basis of an encryption key (which will be described later) inputted
from the control means 84, and outputs encrypted data. The second
multiplexer means 83 receives the encrypted data from the encryptor
means 82, receives an EMI and an OE (header information 101) from
the control means 84, and multiplexed these data. The
above-mentioned first multiplexer means 81, the encryptor means 82,
and the second multiplexer means 83 are referred to as the
encryption unit 80. Here, the first multiplexer means 81, the
encryptor means 82, and the second multiplexer means 83 operate in
synchronization with the same periodic signal. That is, each
periodic signal indicates the cycle of a block and the same
processes are carried out in the section of each periodic signal.
For example, when the start position of the periodic signal is the
start position of a block, the encryptor means 82 makes the start
position of the periodic signal coincide with the start position of
the encryption unit. Then, the second multiplexer means 83
multiplexes Sync data at the start position of the periodic signal.
In addition, the cycle of the periodic signal depends on how many
transmission frames constitutes one block, and for example when one
block consists of eight transmission frames, the periodic signal is
generated in synchronization with eight transmission frames. Here,
the periodic signal may be generated by any apparatus, or supplied
from outside.
[0091] The control means 84 is constituted by a CPU, and receives
the copyright protect information outputted from the digital audio
output apparatus 71, judges on the basis of the information whether
the encryption is performed or not, and when performing the
encryption outputs the encryption key to the encryptor means 82.
The control means further outputs the EMI and the OE as information
indicating how to perform the encryption, to the second multiplexer
means 83.
[0092] The communication means 85 outputs the clock, which is
synchronized with a transmission clock of the transmission line, to
the digital audio output apparatus 71 as well as receives the
multiplexed data from the second multiplexer means 83, and
transmits the encrypted data to the communication means 91 on the
receiving apparatus 73 side.
[0093] The communication means 91 outputs a clock to the digital
audio playback apparatus 74, receives the encrypted data
transmitted from the communication means 85 on the transmission
apparatus 72 side, synchronizes the data with the clock, and
transmits the data to the first demultiplexer means 92.
[0094] The first demultiplexer means 92 receives the data outputted
from the communication means 91, demultiplexes the EMI and the OE
from the received data, transmits the EMI and the OE to the control
means 95, and transmits other data to the decoder means 93. The
decoder means 93 receives the data outputted from the first
demultiplexer means 92, receives an encryption key from the control
means 95, and carries out the decoding process in encryption units.
The second demultiplexer means 94 receives the data outputted from
the decoder means 93, demultiplexes the data into audio data and
copyright protect information, transmits the audio data to the
digital audio playback apparatus 74, and transmits the copyright
protect information to the control means 95. The above-mentioned
first demultiplexer means 92, the decoder means 93 and the second
demultiplexer means 94 are referred to as the decoding unit 90.
Here, the first demultiplexer means 92, the decoder means 93, and
the second demultiplexer means 94 operate in synchronization with
the same periodic signal. This periodic signal is generated by
seeing Sync data on the transmission line. For example, when the
start position of the periodic signal is the start position of a
block, the decoder means 93 makes the start position of the
periodic signal coincide with the start position of the encryption
unit, like in the case of the encryptor means 82.
[0095] The control means 95 is constituted by a CPU, and it
receives the EMI and the OE from the data outputted by the
communication means 91, and outputs the encryption key to the
decoder means 93 on the basis of these information. The control
means further receives the copyright protect information from the
decoded data, and control processes, such as copying of audio data,
on the basis of the information.
[0096] As described above, the transmission apparatus 72 transmits
data in synchronization with the clock outputted from the
communication means 85, whereby conversion of a clock of audio data
is not required, the circuit scale can be reduced, and further
deterioration of the audio quality can be prevented. The first
multiplexer means 81, the encryptor means 82 and the second
multiplexer means 83 may be constituted integrally as the
encryption unit 80 by one semiconductor chip. Further, the
encryption unit 80 and the communication means 85 may be
constituted by one semiconductor chip. The first demultiplexer
means 92, the decoder means 93, and the second demultiplexer means
94 may be constituted integrally as the decoding unit 90 by one
semiconductor chip. Further, the decoding unit 90 and the
communication means 91 may be constituted by one semiconductor
chip.
[0097] Here, the clocks of the transmission apparatus 72 and the
receiving apparatus 73 are supplied through the transmission line,
while when any apparatus is a clock source of the transmission
line, it supplies the clock to the transmission line.
[0098] While here the case where the start position of the periodic
signal is made coincide with the start position of the block has
been described, it is needless to say that as long as positions of
the periodic signal and the block or the periodic signal and the
encryption unit are synchronized with each other, any positional
relationship is possible.
[0099] As described above, according to the transmission system of
the first embodiment, the transmission method for transmitting the
channel assignment information, the sampling frequency information
and the quantization word length information of multi-channel audio
data is decided, whereby transmission of the multi-channel audio
data, which has not been performed conventionally, is enabled.
Since the header information is sent block by block at the
transmission of the multi-channel audio data, efficient data
transmission at smaller bands can be realized, with relative to the
prior art transmission system by which the header information is
transmitted frame by frame.
[0100] Further, according to the transmission system of the first
embodiment, when multi-channel audio data of the DVD-Audio or the
like is transmitted, the copyright protect information can be
multi-transmitted at smaller bands. Further, since one block is
composed of eight frames and the encryption in eight byte units is
carried out block by block, the encryption can be performed up to
the last byte, regardless of the length of the audio data 103.
[0101] The transmission order of audio samples is decided such that
first-generated audio samples are transmitted first, whereby the
amounts of memory required for waiting for timing of
transmission/receiving of data, which are necessary on the
transmission end and the receiving end, can be reduced. Here, the
transmission is performed under time restriction, while it may be
performed in the order of channel numbers, or successively from
audio samples of upper bytes to audio samples of lower bytes. Other
transmission methods can be employed as long as the order in which
data are transmitted is uniquely defined.
[0102] In this first embodiment, the drive of the DVD-Audio is
employed as the digital audio output apparatus 21. However, any
apparatus which outputs arbitrary digital audio data may be applied
thereto, such as a drive of a recording medium such as a CD, a MD,
a DAT and a DVD-Video, a tuner which receives digital audio
broadcasts of digital TV broadcasting or digital radio, an AD
converter which converts analog audio into digital audio and
outputs the digital audio, and a PC which plays back audio data
received via Internet.
[0103] In this first embodiment, data of the receiving apparatus 23
is outputted to the digital audio playback apparatus 24, while any
apparatus which utilizes digital audio may be used, such as an
apparatus for recording digital audio and an apparatus for editing
digital audio.
[0104] Further, in this first embodiment, the transmission method
according to the MOST format is employed, while the present
invention can be applied to any transmission method by which time
slots are included in frames of a prescribed cycle, and a
transmission apparatus and a receiving apparatus for performing
transmission use the time slots which are previously allocated
thereto, to perform the transmission. As an example of such
transmission method, there is a D2B optical (Reference: "The D2B
Optical Bus--An Integration platform for Car Entertainment and
Telematic Systems", by Peter Mros, Proc. of World Congress on
Intelligent Transport Systems Technical Sessions, October 1997).
Further, the transmission line is not limited to the time slot type
but the present invention can be applied to any transmission line
of IEEE 1394 or the like.
[0105] The AUX data is not limited to the example shown in FIG. 4,
while any format data may be employed, as long as it is composed of
sampling frequency information, quantization word length
information and channel assignment information, and the arrangement
of audio data that is to be transmitted is defined. The respective
data of the sampling frequency information, the quantization word
length information and the channel assignment information may be
transmitted by arbitrary frames, whereby an arbitrary number of
bits representing necessary information can be used and thus an
arbitrary value can be employed. Further, in addition to the
sampling frequency information, the quantization word length
information and the channel assignment information, any data which
is required for playback of audio data to be transmitted can be
included, such as conditions for reduction of the sampling
frequency or the quantization word length, and the presence or
absence of emphasis. When the sampling frequency or the
quantization word length has a fixed value, that information is
unnecessary and can be omitted.
[0106] Further, the AUX data is multiplexed with audio data and
transmitted by the synchronous channel. However, at the insertion
of a disc, or at the top of music or when the state of the music is
changed, or at established periods, the AUX data may be transmitted
by an asynchronous channel or the like. Here, the asynchronous
channel is an area that is used to transmit data which does not
require time restriction. As examples of the asynchronous channel,
there are a control channel and an Asynchronous channel, defined in
the MOST. As examples of data transmitted by the control channel,
there are operation command information (playback, fast forward and
the like), and menu information (program list and the like).
Further, as examples of data transmitted by the Asynchronous
channel, there are map data and Internet data (IP packet).
[0107] Furthermore, the format of the block data is not limited to
that shown in FIG. 2. In this first embodiment, one block is
composed of eight frames correspondingly to eight bytes of the
encryption unit, while one block may consists of "a multiple of 8"
frames, as shown in FIG. 10. Further, it is also possible that one
block is composed of 16 frames, the first bytes of first 8 frames
are assumed to be the header, and the first bytes of latter 8
frames are assumed to be areas for auxiliary data. The encryption
unit is not limited to 8 bytes but may be "n" bytes other than 8,
and in this case the number of frames constituting one block is set
to be a multiple of "n". Further, the structure of the block is not
limited to the above-mentioned structures. Any structure is
possible as long as the total amount of data in the encryption area
included in frames which are selected as a block is a multiple of
the encryption unit. In this case, the same effects can be obtained
by using a block that is composed of an arbitrary number of
frames.
[0108] The transmission of respective audio samples is performed
according to the arrangement shown in FIG. 6, while it is not
limited to this arrangement. As long as in which position in a
frame each audio sample of each channel is arranged is decided
between the transmission apparatus and the receiving apparatus, the
audio samples may be arranged arbitrarily. The arrangement can be
decided according to previously decided rules, or an arrangement
method may be shared before the transmission of audio data.
* * * * *