U.S. patent application number 09/903706 was filed with the patent office on 2001-11-29 for data communication apparatus, method and system and programs for data communication process stored in computer readable storage medium.
Invention is credited to Ito, Masamichi, Takahashi, Koji.
Application Number | 20010047443 09/903706 |
Document ID | / |
Family ID | 26368924 |
Filed Date | 2001-11-29 |
United States Patent
Application |
20010047443 |
Kind Code |
A1 |
Ito, Masamichi ; et
al. |
November 29, 2001 |
Data communication apparatus, method and system and programs for
data communication process stored in computer readable storage
medium
Abstract
In a data communication apparatus for encoding information data
by using a predetermined encoding method, encoded information data
is transmitted isochronously with a predetermined communication
cycle when the encoding method corresponds to a decoding method at
an object node apparatus and non-encoded information data is
transmitted asynchronously with the communication cycle when the
encoding method does not correspond to the decoding method at the
object node apparatus. It is therefore possible to perform an
encoding process for the information data to be transmitted, in
accordance with a decoding performance at the object node
apparatus, to improve a communication efficiency, and to reduce a
capacity of a memory used for communications.
Inventors: |
Ito, Masamichi; (Tokyo,
JP) ; Takahashi, Koji; (Chigasaki-shi, JP) |
Correspondence
Address: |
FITZPATRICK CELLA HARPER & SCINTO
30 ROCKEFELLER PLAZA
NEW YORK
NY
10112
US
|
Family ID: |
26368924 |
Appl. No.: |
09/903706 |
Filed: |
July 13, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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|
09903706 |
Jul 13, 2001 |
|
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09024187 |
Feb 17, 1998 |
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6298405 |
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Current U.S.
Class: |
710/107 ;
709/229 |
Current CPC
Class: |
G06F 3/1236 20130101;
G06F 3/1208 20130101; G06F 3/1284 20130101 |
Class at
Publication: |
710/107 ;
709/229 |
International
Class: |
G06F 015/16; G06F
013/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 14, 1997 |
JP |
9-030543 |
Apr 7, 1997 |
JP |
9-088430 |
Claims
What is claimed is:
1. A data communication apparatus, comprising: (a) communication
means having a first mode of transmitting information data
isochronously with a predetermined communication cycle and a second
mode of transmitting information data asynchronously with the
predetermined communication cycle; (b) encoding means for encoding
the information data by a predetermined encoding method; and (c)
control means for controlling said communication means so as to
transmit encoded information data when the encoding method
corresponds to a decoding method at an object node apparatus and to
transmit non-encoded information data when the encoding method does
not correspond to the decoding method at the object node
apparatus.
2. A data communication apparatus according to claim 1, wherein
said control means controls so as to transmit information data
encoded by using the first or second mode, when the encoding method
corresponds to the decoding method at the object node
apparatus.
3. A data communication apparatus according to claim 2, wherein
said control means controls so as to transmit by using the first
mode when the information data is moving image data.
4. A data communication apparatus according to claim 1, wherein
said control means controls so as to transmit information data
encoded by using the first or second mode, when the encoding method
does not correspond to the decoding method at the object node
apparatus.
5. A data communication apparatus according to claim 4, wherein
said control means controls so as to transmit by using the second
mode when the information data is still image data.
6. A data communication apparatus according to claim 1, wherein
said communication means transmits the information data to the
object node apparatus via a data bus.
7. A data communication apparatus according to claim 1, wherein
communication using the first mode and communication using the
second mode can be mixed in the communication cycle.
8. A data communication apparatus according to claim 1, wherein the
first mode has a higher priority over the second mode in the
communication cycle.
9. A data communication apparatus according to claim 1, wherein the
first mode is in conformity with an isochronous transmission mode
of IEEE 1394 specifications, and the second mode is in conformity
with an asynchronous transmission mode of IEEE 1394
specifications.
10. A data communication apparatus according to claim 1, wherein
the non-encoded information data includes information data once
encoded and thereafter decoded.
11. A data communication apparatus according to claim 1, wherein
the information data contains moving image data or still image
data.
12. A data communication apparatus according to claim 1, wherein
the data communication apparatus is a digital video camera equipped
with an image pickup unit for generating digital image information
from an optical image of a subject.
13. A data communication apparatus according to claim 1, wherein
the data communication apparatus is a video recorder for recording
image information encoded by said encoding means in a predetermined
storage medium.
14. A data communication apparatus, comprising: (a) communication
means having a first mode of communication isochronous with a
predetermined communication cycle and a second mode of
communication asynchronous with the communication cycle; (b)
encoding means for encoding image information in accordance with a
decoding performance at an object node apparatus, the image
information including moving image information and still image
information; and (c) control means for controlling said
communication means so as to transmit the moving image information
by using the first mode and to transmit the still image information
by using the second mode.
15. A data communication apparatus according to claim 14, wherein
said control means controls said communication means transmits the
still image information by using the first mode when a plurality
set of still image information are sequentially transmitted.
16. A data communication apparatus according to claim 14, wherein
the still image information is contained in the moving image
information.
17. A data communication apparatus according to claim 14, wherein
the data communication apparatus is a digital video camera equipped
with an image pickup unit for generating digital image information
from an optical image of a subject.
18. A data communication apparatus according to claim 14, wherein
the data communication apparatus is a video recorder for recording
image information encoded by said encoding means in a predetermined
storage medium.
19. A data communication apparatus, comprising: (a) input means for
inputting moving image information and still image information; (b)
encoding means for encoding the moving image information and the
still image information; and (c) transmitting means for
transmitting the moving image to a number of unidentified
apparatuses and transmitting the still image information to a
designated apparatus.
20. A data communication apparatus according to claim 19, wherein
said transmitting means transmits the moving image information by
using a transmission bandwidth assigned to each predetermined
communication cycle and transmitting the still image information by
using an idle bandwidth of the communication cycle.
21. A data communication apparatus according to claim 19, wherein
said encoding means encodes the moving image information and the
still image information by using an encoding performance
corresponding to a decoding method at an object node apparatus.
22. A data communication apparatus, comprising: (a) input means for
inputting information data; (b) encoding means for encoding the
information data; and (c) transmitting means for transmitting
decode information containing program codes realizing the decoding
method corresponding to an encoding method to be used by said
encoding means and transmitting the information data encoded by
said encoding means.
23. A data communication apparatus according to claim 22, wherein
the decode information contains control data for inhibiting to use
the program codes under predetermined conditions.
24. A data communication apparatus according to claim 22, wherein
the information data includes image data.
25. A data communication apparatus, comprising: (a) input means for
inputting encoded information data and decode information realizing
a decoding process for the information data; and (b) decoding means
for decoding the encoded information data by using the decode
information.
26. A data communication apparatus, comprising: (a) encoding means
for encoding information data by using a predetermined encoding
method; (b) decoding means for decoding information data encoded by
said encoding means; and (c) selecting means for selecting an
output of either said encoding means or sad decoding means in
accordance with whether the encoding method corresponds to a
decoding method at an object node apparatus.
27. A data communication method, comprising the steps of: (a)
encoding information data by a predetermined encoding method; (b)
transmitting encoded information data isochronously with a
predetermined communication cycle when the encoding method
corresponds to a decoding method at an object node apparatus; and
(c) transmitting non-encoded information data asynchronously with
the communication cycle when the encoding method does not
correspond to the decoding method at the object node apparatus.
28. A data communication method, comprising the steps of: (a)
encoding image information in accordance with a decoding
performance at an object node apparatus, the image information
including moving image information and still image information; (b)
transmitting the moving image information by using a communication
scheme isochronous with a predetermined communication cycle; and
(c) transmitting the still image by the communication scheme
isochronous with the communication cycle or by a communication
scheme asynchronous with the communication cycle.
29. A data communication method, comprising the steps of: (a)
inputting moving image information and still image information; (b)
encoding the moving image information and the still image
information; and (c) transmitting the moving image to a number of
unidentified apparatuses and transmitting the still image
information to a designated apparatus.
30. A data communication method, comprising the steps of: (a)
inputting information data; (b) encoding the information data; and
(c) transmitting decode information containing program codes
realizing the decoding method corresponding to an encoding method
to be used at said encoding step and transmitting the information
data encoded at said encoding step.
31. A data communication method, comprising the steps of: (a)
inputting encoded information data and decode information realizing
a decoding process for the information data; and (b) decoding the
encoded information data by using the decode information.
32. A data communication method, comprising the steps of: (a)
encoding information data by using a predetermined encoding scheme;
(b) decoding information data encoded at said encoding step; and
(c) selecting an output of either the encoded information data or
the decoded information data in accordance with whether the
encoding scheme corresponds to a decoding scheme at an object node
apparatus.
33. A data communication system having a first mode of transmitting
information data isochronously with a predetermined communication
cycle and a second mode of transmitting information data
asynchronously with the predetermined communication cycle, wherein
encoded information data is transmitted when a predetermined
encoding scheme corresponds to a decoding scheme at an object node
apparatus and non-encoded information data is transmitted when the
encoding scheme does not correspond to the decoding scheme at the
object node apparatus.
34. A data communication system having a first mode of
communication isochronous with a predetermined communication cycle
and a second mode of communication asynchronous with the
communication cycle, wherein moving image information encoded in
accordance with a decoding performance at an object node apparatus
is transmitted by using the first mode and still image information
encoded in accordance with the decoding performance at the object
node apparatus is transmitted by using the first or second
mode.
35. A data communication system, comprising: (a) a transmission
apparatus for transmitting decode information containing program
codes realizing a decoding method corresponding to a predetermined
encoding method and transmitting information data encoded by using
the encoding method; and (b) a reception apparatus for receiving
the decode information and the information data and decoding the
information data by using the decode information.
36. A program for a data communication process stored in a computer
readable storage medium, comprising the steps of: (a) encoding
information data by a predetermined encoding method; (b)
transmitting encoded information data isochronously with a
predetermined communication cycle when the encoding method
corresponds to a decoding method at an object node apparatus; and
(c) transmitting non-encoded information data asynchronously with
the communication cycle when the encoding method does not
correspond to the decoding method at the object node apparatus.
37. A program for a data communication process stored in a computer
readable storage medium, comprising the steps of: (a) encoding
image information in accordance with a decoding performance at an
object node apparatus, the image information including moving image
information and still image information; (b) transmitting the
moving image information by using a communication scheme
isochronous with a predetermined communication cycle; and (c)
transmitting the still image by the communication scheme
isochronous with the communication cycle or by a communication
scheme asynchronous with the communication cycle.
38. A program for a data communication process stored in a computer
readable storage medium, comprising the steps of: (a) inputting
moving image information and still image information; (b) encoding
the moving image information and the still image information; and
(c) transmitting the moving image to a number of unidentified
apparatuses and transmitting the still image information to a
designated apparatus.
39. A program for a data communication process stored in a computer
readable storage medium, comprising the steps of: (a) inputting
information data; (b) encoding the information data; and (c)
transmitting decode information containing program codes realizing
the decoding method corresponding to an encoding method to be used
at said encoding step and transmitting the information data encoded
at said encoding step.
40. A program for a data communication process stored in a computer
readable storage medium, comprising the steps of: (a) inputting
encoded information data and decode information realizing a
decoding process for the information data; and (b) decoding the
encoded information data by using the decode information.
41. A program for a data communication process stored in a computer
readable storage medium, comprising the steps of: (a) encoding
information data by using a predetermined encoding scheme; (b)
decoding information data encoded at said encoding step; and (c)
selecting an output of either the encoded information data or the
decoded information data in accordance with whether the encoding
scheme corresponds to a decoding scheme at an object node
apparatus.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a data communication
apparatus, method and system, and to programs for a data
communication process stored in a computer readable storage medium.
More particularly, the invention relates to data communication
techniques using communication control buses capable of dealing
with mixed control and data signals.
[0003] 2. Related Background Art
[0004] A need for using an apparatus dealing with still or moving
images, such as AV (audio visual) apparatuses, as a peripheral
apparatus of a personal computer has recently become strong. The AV
apparatuses include a digital video tape recorder (D-VTR), a
digital video tape recorder with a built-in camera (D-CAM), a
digital camera, and the like. For such needs, a system has been
developed which can connect such AV apparatuses to PC and can
process and edit in various ways digital signals of still and
moving images taken with AV apparatuses. Another system has also
been developed in which PC can record still and moving image
signals from AV apparatuses in a recording medium such as a hard
disk, and can print such images with an image printing apparatus
such as a printer.
[0005] In order to reduce the amount of still and moving image data
to be transferred between apparatuses constituting such a system,
the image data is converted into compressed data by using various
compression encoding techniques. For example, a JPEG (Joint
Photographic Experts Group) method is known for still images, and
an MPEG (Moving Picture Experts Group) method is known for moving
images. These compression encoding methods are realized by a
combination of DCT techniques and variable length coding
techniques, while taking into consideration the characteristics and
features of image data to be compressed.
[0006] FIG. 1 is a block diagram showing the structure of a
conventional communication system. In FIG. 1, reference numeral 101
represents a D-CAM (recording/reproducing device), 102 represents a
printer, and 103 represents a PC. PC 103 and the printer 102 are
interconnected by communication interfaces of SCSI (small computer
system interface) specifications. PC 103 and D-CAM 101 are
interconnected by dedicated communication interfaces.
[0007] In the communication system shown in FIG. 1, for example,
the following processes have been executed in printing a still
image contained in moving images reproduced with D-CAM 101.
[0008] PC 103 temporarily stores moving image data sequentially
output from D-CAM 101 in a storage device such as a hard disk.
Next, PC 103 reproduces the moving images by using a predetermined
application, and selects a desired still image of one frame from
the moving images. In this case, a user performs a special effect
process for the selected still image, if necessary, and thereafter
instructs to print the still image. In response to this
instruction, PC 103 supplies the still image data to the printer
102 connected thereto via a communication interface different from
that for D-CAM 101. Lastly, the printer 102 prints out the still
image. As above, the communication system shown in FIG. 1 prints a
still image contained in moving images with the help of PC 102.
[0009] With the communication system described above, however, in
order to select a desired still image contained in moving images
produced with D-CAM 101, the moving image is required to be
temporarily stored in the storage device such as a hard disk of PC
103. PC 103 then reproduces moving image data stored in the storage
device to select a desired still image.
[0010] In the conventional communication system, therefore, a large
amount of data such as moving image data is sequentially sent to PC
103 each time in the unit of a predetermined amount of data, so
that a load of PC 103 is very large. Depending upon the process
performance and condition of PC 103 itself or upon a communication
state of each apparatus, PC 103 may become inoperative or adversely
affect the communication with other apparatuses. Furthermore, since
a desired still image is selected after the moving image data
stored in PC 103 is reproduced, it takes a long time to print the
still image.
[0011] In the communication system shown in FIG. 1, in order to
reduce the amount of moving image data to be transmitted from D-CAM
101 to PC 103, the moving image data is compressed at D-CAM 101 by
a predetermined compression encoding scheme, and the compressed
data is transmitted to PC 103.
[0012] However, even if D-CAM 101 transmits compressed moving image
data, a desired still image cannot be selected unless PC 103 itself
can expand and decode the compressed moving image data.
[0013] In the communication system shown in FIG. 1, if moving image
data irrelevant to the compression coding scheme used by PC 103 is
to be transmitted, D-CAM 101 has conventionally transmitted
non-compressed moving data itself to PC 103.
[0014] However, if PC 103 has an expansion decoding scheme
corresponding to the compression encoding scheme of D-CAM 101, a
transmission efficiency is lowered unnecessarily and a load on PC
103 is increased.
SUMMARY OF THE INVENTION
[0015] An object of the present invention is to solve the
above-described problems.
[0016] Another object of the invention is to provide a data
communication apparatus in which an encoding process for
information data to be transmitted is performed in accordance with
a decoding performance at an object node apparatus, to thereby
improve the communication efficiency and reduce a capacity of a
memory used for communications.
[0017] As a preferred embodiment for such objects, the invention
discloses a data communication apparatus which comprises: (a)
communication means having a first mode of transmitting information
data isochronously with a predetermined communication cycle and a
second mode of transmitting information data asynchronously with
the predetermined communication cycle; (b) encoding means for
encoding the information data by a predetermined encoding method;
and (c) control means for controlling the communication means so as
to transmit encoded information data when the encoding method
corresponds to a decoding method at an object node apparatus and to
transmit non-encoded information data when the encoding method does
not correspond to the decoding method at the object node
apparatus.
[0018] As another embodiment, the invention discloses a data
communication apparatus which comprises: (a) communication means
having a first mode of communication isochronous with a
predetermined communication cycle and a second mode of
communication asynchronous with the communication cycle; (b)
encoding means for encoding image information in accordance with a
decoding performance at an object node apparatus, the image
information including moving image information and still image
information; and (c) control means for controlling the
communication means so as to transmit the moving image information
by using the first mode and to transmit the still image information
by using the second mode.
[0019] As another embodiment, the invention discloses a data
communication apparatus which comprises: (a) input means for
inputting moving image information and still image information; (b)
encoding means for encoding the moving image information and the
still image information; and (c) transmitting means for
transmitting the moving image to a number of unidentified
apparatuses and transmitting the still image information to a
designated apparatus.
[0020] As another embodiment, the invention discloses a data
communication apparatus which comprises: (a) input means for
inputting information data; (b) encoding means for encoding the
information data; and (c) transmitting means for transmitting
decode information containing program codes realizing the decoding
method corresponding to an encoding method to be used by the
encoding means and transmitting the information data encoded by the
encoding means.
[0021] As another embodiment, the invention discloses a data
communication apparatus which comprises: (a) input means for
inputting encoded information data and decode information realizing
a decoding process for the information data; and (b) decoding means
for decoding the encoded information data by using the decode
information.
[0022] As another embodiment, the invention discloses a data
communication apparatus which comprises: (a) encoding means for
encoding information data by using a predetermined encoding method;
(b) decoding means for decoding information data encoded by the
encoding means; and (c) selecting means for selecting an output of
either the encoding means or the decoding means in accordance with
whether the encoding method corresponds to a decoding method at an
object node apparatus.
[0023] Another object of the present invention is to provide a data
communication method in which an encoding process for information
data to be transmitted is performed in accordance with a decoding
performance at an object node apparatus, to thereby improve the
communication efficiency and reduce a capacity of a memory used for
communications.
[0024] As a preferred embodiment for such an object, the invention
discloses a data communication method which comprises the steps of:
(a) encoding information data by a predetermined encoding method;
(b) transmitting encoded information data isochronously with a
predetermined communication cycle when the encoding method
corresponds to a decoding method at an object node apparatus; and
(c) transmitting non-encoded information data asynchronously with
the communication cycle when the encoding method does not
correspond to the decoding method at the object node apparatus.
[0025] As another embodiment, the invention discloses a data
communication method which comprises the steps of: (a) encoding
image information in accordance with a decoding performance at an
object node apparatus, the image information including moving image
information and still image information; (b) transmitting the
moving image information by using a communication scheme
isochronous with a predetermined communication cycle; and (c)
transmitting the still image by the communication scheme
isochronous with the communication cycle or by a communication
scheme asynchronous with the communication cycle.
[0026] As another embodiment, the invention discloses a data
communication method which comprises the steps of: (a) inputting
moving image information and still image information; (b) encoding
the moving image information and the still image information; and
(c) transmitting the moving image to a number of unidentified
apparatuses and transmitting the still image information to a
designated apparatus.
[0027] As another embodiment, the invention discloses a data
communication method which comprises the steps of: (a) inputting
information data; (b) encoding the information data; and (c)
transmitting decode information containing program codes realizing
the decoding method corresponding to an encoding method to be used
at the encoding step and transmitting the information data encoded
at the encoding step.
[0028] As another embodiment, the invention discloses a data
communication method which comprises the steps of: (a) inputting
encoded information data and decode information realizing a
decoding process for the information data; and (b) decoding the
encoded information data by using the decode information.
[0029] As another embodiment, the invention discloses a data
communication method which comprises the steps of: (a) encoding
information data by using a predetermined encoding scheme; (b)
decoding information data encoded at the encoding step; and (c)
selecting an output of either the encoded information data or the
decoded information data in accordance with whether the encoding
scheme corresponds to a decoding scheme at an object node
apparatus.
[0030] Another object of the present invention is to provide a data
communication system in which an encoding process for information
data to be transmitted is performed in accordance with a decoding
performance at an object node apparatus, to thereby improve the
communication efficiency and reduce a capacity of a memory used for
communications.
[0031] As a preferred embodiment for such an object, the invention
discloses a data communication system having a first mode of
transmitting information data isochronously with a predetermined
communication cycle and a second mode of transmitting information
data asynchronously with the predetermined communication cycle,
wherein encoded information data is transmitted when a
predetermined encoding scheme corresponds to a decoding scheme at
an object node apparatus and non-encoded information data is
transmitted when the encoding scheme does not correspond to the
decoding scheme at the object node apparatus.
[0032] As another embodiment, the invention discloses a data
communication system having a first mode of communication
isochronous with a predetermined communication cycle and a second
mode of communication asynchronous with the communication cycle,
wherein moving image information encoded in accordance with a
decoding performance at an object node apparatus is transmitted by
using the first mode and still image information encoded in
accordance with the decoding performance at the object node
apparatus is transmitted by using the first or second mode.
[0033] As another embodiment, the invention discloses a data
communication system, comprising: (a) a transmission apparatus for
transmitting decode information containing program codes realizing
a decoding method corresponding to a predetermined encoding method
and transmitting information data encoded by using the encoding
method; and (b) a reception apparatus for receiving the decode
information and the information data and decoding the information
data by using the decode information.
[0034] Another object of the present invention is to provide a
program for a data communication process stored in a computer
readable storage medium, in which an encoding process for
information data to be transmitted is performed in accordance with
a decoding performance at an object node apparatus, to thereby
improve the communication efficiency and reduce a capacity of a
memory used for communications.
[0035] As a preferred embodiment for such an object, the invention
discloses a program for a data communication process stored in a
computer readable storage medium, comprising the steps of: (a)
encoding information data by a predetermined encoding method; (b)
transmitting encoded information data isochronously with a
predetermined communication cycle when the encoding method
corresponds to a decoding method at an object node apparatus; and
(c) transmitting non-encoded information data asynchronously with
the communication cycle when the encoding method does not
correspond to the decoding method at the object node apparatus.
[0036] As another embodiment, the invention discloses a program for
a data communication process stored in a computer readable storage
medium, comprising the steps of: (a) encoding image information in
accordance with a decoding performance at an object node apparatus,
the image information including moving image information and still
image information; (b) transmitting the moving image information by
using a communication scheme isochronous with a predetermined
communication cycle; and (c) transmitting the still image by the
communication scheme isochronous with the communication cycle or by
a communication scheme asynchronous with the communication
cycle.
[0037] As another embodiment, the invention discloses a program for
a data communication process stored in a computer readable storage
medium, comprising the steps of: (a) inputting moving image
information and still image information; (b) encoding the moving
image information and the still image information; and (c)
transmitting the moving image to a number of unidentified
apparatuses and transmitting the still image information to a
designated apparatus.
[0038] As another embodiment, the invention discloses a program for
a data communication process stored in a computer readable storage
medium, comprising the steps of: (a) inputting information data;
(b) encoding the information data; and (c) transmitting decode
information containing program codes realizing the decoding method
corresponding to an encoding method to be used at the encoding step
and transmitting the information data encoded at the encoding
step.
[0039] As another embodiment, the invention discloses a program for
a data communication process stored in a computer readable storage
medium, comprising the steps of: (a) inputting encoded information
data and decode information realizing a decoding process for the
information data; and (b) decoding the encoded information data by
using the decode information.
[0040] As another embodiment, the invention discloses a program for
a data communication process stored in a computer readable storage
medium, comprising the steps of: (a) encoding information data by
using a predetermined encoding scheme; (b) decoding information
data encoded at the encoding step; and (c) selecting an output of
either the encoded information data or the decoded information data
in accordance with whether the encoding scheme corresponds to a
decoding scheme at an object node apparatus.
[0041] Still other objects of the present invention, and the
advantages thereof, will become fully apparent from the following
detailed description of the embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] FIG. 1 is a schematic diagram showing the structure of a
conventional communication system.
[0043] FIG. 2 is a schematic diagram showing the structure of a
communication system according to a first embodiment of the
invention.
[0044] FIG. 3 is a schematic diagram showing an example of a
communication system in conformity with IEEE 1394
specifications.
[0045] FIG. 4 is a diagram showing constituents of a 1394
interface.
[0046] FIG. 5 is a diagram showing the address space of a 1394
interface.
[0047] FIG. 6 is a cross sectional view of a communication cable in
conformity with IEEE 1394 specifications.
[0048] FIG. 7 is a diagram illustrating a DS-Link coding
scheme.
[0049] FIG. 8 is a schematic diagram showing an example of a
communication system in conformity with IEEE 1394
specifications.
[0050] FIG. 9 is a flow chart illustrating the processes from bus
reset to the start of data transfer.
[0051] FIG. 10 is a flow chart illustrating the processes of
discriminating a parent/child relationship (membership) of
communication ports at respective nodes.
[0052] FIG. 11 is a flow chart illustrating the processes of
automatically setting a node ID of each node.
[0053] FIGS. 12A and 12B are diagrams illustrating arbitration of a
1394 interface.
[0054] FIG. 13 is a diagram showing a time sequential transition
state during asynchronous transmission.
[0055] FIG. 14 shows an example of a packet format used by
asynchronous transmission.
[0056] FIG. 15 is a diagram showing a time sequential transition
state during isochronous transmission.
[0057] FIG. 16 shows an example of a packet format used by
isochronous transmission.
[0058] FIG. 17 is a diagram illustrating both isochronous and
asynchronous transmissions in one communication cycle.
[0059] FIG. 18 is a diagram showing the details of the structure of
the communication system shown in FIG. 2.
[0060] FIG. 19 is a flow chart illustrating the operation of the
recording/reproducing device shown in the first embodiment.
[0061] FIG. 20 is a flow chart illustrating the exemplary operation
of the communication system of the first embodiment.
[0062] FIG. 21 is a diagram illustrating moving image and still
image data transmitted in the communication system of the first
embodiment.
[0063] FIG. 22 is a diagram showing the structure of a
communication system according to a second embodiment of the
invention.
[0064] FIG. 23 is a flow chart illustrating the exemplary operation
of the communication system of the second embodiment.
[0065] FIG. 24 is a diagram illustrating moving image and still
image data transmitted in the communication system of the second
embodiment.
[0066] FIG. 25 is a diagram showing the structure of a monitor
shown in the second embodiment.
[0067] FIG. 26 is a schematic diagram showing the structure of a
communication system according to third and fourth embodiments of
the invention.
[0068] FIG. 27 is a diagram showing the details of a
recording/reproducing device and a printer shown in the third and
fourth embodiments.
[0069] FIG. 28 is a flow chart illustrating the exemplary operation
of the recording/reproducing device shown in the third
embodiment.
[0070] FIG. 29 is a flow chart illustrating the exemplary operation
of the recording/reproducing device shown in the fourth
embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0071] The preferred embodiments of the present invention will now
be described in detail hereinafter with reference to the
accompanying drawings.
[0072] 1. First Embodiment
[0073] FIG. 2 is a diagram showing a communication system according
to a first embodiment of the invention. This communication system
can perform communications in conformity with IEEE 1394-1995
specifications (hereinafter called IEEE 1394 specifications).
[0074] Apparatuses constituting the communication system shown in
FIG. 2 have communication interfaces in conformity with IEEE 1394
specifications (hereinafter called 1394 interfaces). The
apparatuses are interconnected by communication cables in
conformity with IEEE 1394 specifications.
[0075] Technologies of IEEE 1394 specifications will be briefly
described. The details of IEEE 1394 specifications are given in
"IEEE 1394-1995 Standard for a High Performance Serial Bus"
published by IEEE (Institute of Electrical and Electronics
Engineers).
[0076] <Summary>
[0077] FIG. 3 shows an example of a communication system in
conformity with IEEE 1394 specifications. This communication system
configures a bus type network capable of serial data
communications.
[0078] In FIG. 3, apparatuses A to H are interconnected by twist
pair cables in conformity with IEEE 1394 specifications. Examples
of these apparatuses are a PC (Personal Computer), a digital VTR
(Video Tape Recorder), a DVD (Digital Video Disc) player, a digital
camera, a hard disk, a monitor and the like.
[0079] As the interconnection method for the communication system
shown in FIG. 3, daisy chain and node branch are both used so that
a high degree of connection freedom is possible.
[0080] The communication system shown in FIG. 3 automatically
executes a bus reset (a process of resetting the past network
configuration and re-recognizing the new network configuration)
when any apparatus is disconnected from the network, when a new
apparatus is connected to the network, or when the power of an
apparatus connected to the network is turned on or off. With this
bus reset, the communication system can automatically assign each
apparatus with its specific ID, or each apparatus constituting the
communication system can automatically recognize the network
connection. With these functions, the 1394 network can recognize
the network configuration at any time.
[0081] The communication system shown in FIG. 3 has a function of
relaying data from one apparatus to another, and each apparatus can
recognize the bus operation state at the same time. Furthermore,
the communication system has a function called Plug & Play so
that an apparatus connected to the network or the connection state
of the network can be automatically recognized without turning the
power of the whole network off.
[0082] The communication system shown in FIG. 3 can deal with the
data transmission rates of 100/200/400 Mbps. The apparatus having a
higher transmission rate supports the apparatus having a lower
transmission rate to make them compatible.
[0083] The communication system shown in FIG. 3 has two different
data transmission modes including an asynchronous transmission mode
and an isochronous transmission mode. The asynchronous transmission
mode is suitable for transmitting data required to be
asynchronously transmitted when necessary (such as control signals
and file data). The isochronous transmission mode is suitable for
transmitting data required to be transmitted continuously at a
predetermined data rate (such as video data and audio data). Both
the asynchronous and isochronous transmission modes may be used in
each communication cycle (generally 125 .mu.s). Each transmission
mode is executed after a cycle start packet (CSP) indicating the
start of a cycle is transmitted. In each communication cycle
period, the isochronous transmission mode has a priority order
higher than the asynchronous transmission mode. The transmission
bandwidth of the isochronous transmission mode is ensured or
reserved in each communication cycle.
[0084] <Architecture>
[0085] The constituents of an 1394 interface are shown in FIG.
4.
[0086] The 1394 interface is functionally configured to have a
layer (hierarchical) structure. As shown in FIG. 4, reference
numeral 401 represents a communication cable in conformity with
IEEE 1394 specifications. This cable 401 is connected via a
connector port 402 of the 1394 interface to a physical layer 403
and to a link layer 404 in a hardware portion.
[0087] The hardware portion is substantially an interface chip. Of
the hardware portion, the physical layer 403 controls a bus reset,
encoding/decoding of input/output signals, and the like. The link
layer 404 generates a communication packet, controls a cycle timer,
and performs other operations.
[0088] A transaction layer 405 of a firmware portion performs
management of data to be transmitted and manages Read and Write
transactions. A serial bus management 406 performs the management
of connection state and ID of each apparatus connected to the
system to thereby manage the network configuration and
information.
[0089] These hardware and software are the substantial structure of
the 1394 interface.
[0090] An application layer 407 shown in FIG. 4 becomes different
depending upon software to be used. This layer defines how data is
communicated over the communication system. For example, in the
case of moving image data of a D-VTR, data communication is defined
in accordance with a communication protocol such as an AV/C
protocol.
[0091] <Address Designation>
[0092] FIG. 5 shows an address space of the 1394 interface.
[0093] Addressing of an 1394 interface is in conformity with IEEE
1212 which defines an address space of a 64-bit width. In
addressing, the first 10-bit field is used for designating a bus ID
number, and the next 6-bit field (502) is used for designating the
apparatus (node) ID. These upper 16 bits are used for identifying a
node ID and for communications between nodes. The remaining 48-bit
field designates an address space assigned to the apparatus. In
this field, a 20-bit field (403) designates a plurality areas
constituting the address space (i.e., an initial memory space, a
private space, a register space). The last 28-bit field (404)
designates an address for a specific data area in which information
of apparatus discrimination (company name, apparatus type and the
like) and use condition is stored.
[0094] <Structure of Communication Cable>
[0095] FIG. 6 is a cross sectional view of a communication cable in
conformity with IEEE 1394 specifications.
[0096] The communication cable has power lines in addition to two
pairs of twist pair signal lines. Therefore, an apparatus without a
power source or an apparatus with a power supply voltage lowered by
some trouble can be supplied with power via the power lines by the
1394 interface.
[0097] A communication cable of a 4-pin type may also be used
without using power lines. It is stipulated that a power supply
voltage at the power line is 8 to 40 V, and a current is DC 1.5 A
at a maximum.
[0098] Signals encoded by DS-Link (Data/Strobe Link) coding scheme
are transmitted over the two pairs of twist pair signal lines.
[0099] FIG. 7 illustrates the DS-Link (Data/Strobe Link) coding
scheme.
[0100] This DS-Link coding scheme is suitable for high speed serial
data communications. It is necessary to use two pairs of signal
lines. One pair of two twist pair signal lines is used for
transmitting data signals, and the other of two twist pair signal
lines is used for transmitting strobe signals.
[0101] On the reception side, a clock can be retrieved by an
exclusive logical sum of the transmitted data and strobe
signals.
[0102] The merits of the DS-Link coding scheme are as follows. A
transmission efficiency is higher than other coding schemes. Since
a PLL circuit is not necessary, the scale of a controller LSI can
be made small. Since it is not necessary to transmit information
representative of an idle state when there is no data to be
transmitted, a transceiver circuit of each equipment can enter a
sleep state and a power consumption can be lowered.
[0103] <Bus Reset Sequence>
[0104] The 1394 interface recognizes the network configuration by
assigning each apparatus (node) connected to the network with a
node ID.
[0105] When the network configuration varies with, for example, a
change in the number of nodes to be caused by node
connection/disconnection or power turn-on/off, and it becomes
necessary to recognize a new network configuration. A node which
detected a change transmits a bus reset signal to the bus to enter
a mode of recognizing a new network configuration. This change is
detected by a change in a bias voltage applied to the communication
port 402.
[0106] When the bus reset signal is transmitted from a node to the
network, the physical layer 403 of each node notifies the link
layer 404 of a bus reset occurrence, and transmits the bus reset
signal to other nodes. After the bus reset signal is transmitted to
all nodes, a bus reset (i.e., a process of initializing the
connection state and re-recognizing a new connection state) is
activated.
[0107] The bus reset may be activated through hardware detection of
a cable connection/disconnection, a network abnormality or the like
and through a direct command issued to the physical layer 403 under
host control using a protocol.
[0108] As the bus reset is activated, data transmission is
temporarily stopped and enters a standby state. After the
completion of the bus rest, the data transmission resumes under the
new network configuration.
[0109] <Sequence of Node ID Determination>
[0110] In order to recognize the new network connection state after
the bus reset, the 1394 interface executes a process of setting a
node ID (constituted of a bus number and a node number) to each
node. A general sequence from the start of a bus reset to the end
of setting a node ID will be described with reference to FIGS. 8 to
11.
[0111] FIG. 8 is a diagram illustrating the exemplary operation of
a communication system in conformity with IEEE 1394 specifications.
In the example shown in FIG. 8, each node is connected to the same
bus so that the same bus number is used for each node.
[0112] Referring to FIG. 8, reference numeral 801 represents a node
A having one communication port, reference numeral 3002 represents
a node B having two communication ports, reference numeral 803
represents a node C having two communication ports, reference
numeral 3004 represents a node D having three communication ports,
reference numeral 805 represents a node E having one communication
port, and reference numeral 3006 represents a node F having one
communication port. The communication port of each node is assigned
a port number for discriminating between ports.
[0113] With reference to the flow chart shown in FIG. 9, the
processes to be executed by the communication system shown in FIG.
8, from the bus reset to the data transfer start, will be
described.
[0114] In FIG. 9, each node A to F constituting the communication
system always monitors whether a bus reset occurs in the network.
When a bus reset signal is output because of a change in the
network configuration to be caused by, for example, a node power
on-off, each node executes the following processes.
[0115] Each node declares a membership determination of its
communication ports in order to re-recognize the new connection
state of the network (Step S902). Each node of the network repeats
the process at Step S902 until the membership between all nodes is
determined (Step S903). After the membership between all nodes on
the network is determined, the communication system determines a
node which arbitrates the network, i.e., a root (Step S904).
[0116] After the root is determined, the 1394 interface
automatically assigns each node with a node ID (Step S905). The
root repeats the process at Step S905 until all nodes are assigned
with node IDs in accordance with a predetermined procedure (Step
S906). After all nodes are assigned with node IDs, the 1394
interface executes data transmission between nodes (Step S907).
[0117] After the process at Step S907, the 1394 interface monitors
again an occurrence of a bus reset, and when a bus reset occurs,
the processes from Step S901 are executed.
[0118] In the above manner, with the 1394 interface, all nodes can
recognize the network configuration through automatic assignment of
each node ID by the root determined at each bus reset.
[0119] FIG. 10 is a flow chart illustrating the details of the
process at Step S902 shown in FIG. 9, i.e., the process of
recognizing the membership between node communication ports.
[0120] Referring to FIG. 10, each node A to F constituting the
communication system confirms in response to the bus reset the
connection state (connection or disconnection) of its communication
port or ports, in order to judge whether the node is a leaf (node
connected to only one apparatus) or a branch (node connected to a
plurality of apparatuses) (Step S1001). The number of
communications ports connected to other nodes is counted (Step
S1002).
[0121] If it is judged at Step S1002 that the number of connected
ports is "1", the node recognizes itself as a leaf (Step S1003).
This leaf node declares to the node connected to the port that "I
am a child and you are a parent" (Step S1004). The leaf recognizes
its connection port as a "child port".
[0122] Declaration of the membership between communication ports
can be made by a leaf node, because the leaf node has only one
connected port, i.e., the leaf node is an outermost terminal of the
network. The membership between communication ports is determined
sequentially in the order of faster declaration, in which the
communication port at the declaring communication node is
determined as a child port and the communication port at the
declared communication node is determined as a parent port. For
example, in the example shown in FIG. 8, the nodes A, E and F
recognize themselves as a leaf and thereafter declare the
membership. Therefore, a child-parent membership is determined
between nodes A-B, a child-parent membership is determined between
nodes E-D, and a child-parent membership is determined between
nodes F-D.
[0123] If it is judged at Step S1002 that the number of connected
ports is "2" or larger, this node recognizes itself as a branch
(Step S1005). The branch node receives the membership declaration
from each node connected to its connection port (Step S1006). The
connection port received the declaration is recognized as the
parent port.
[0124] After the parent port is recognized, the branch checks
whether there is any connection port (undefined port) whose
membership is still not determined (Step S1007).
[0125] If there is an undefined port at Step S1007, it is checked
whether the number of undefined ports is "1" (Step S1008). If "1",
the branch recognizes the undefined port as the child port and
declares to the node connected to the port that "I am a child and
you are a parent" (Step S1009).
[0126] The branch cannot declare to another node that "I am a
child" until the number of remaining undefined ports becomes "1".
In the example shown in FIG. 8, the nodes B, C and D recognize
themselves as a branch, and receive a declaration from another
branch or leaf. After the memberships between D-E and D-F are
determined, the node D declares the membership to the node C. Upon
reception of the declaration from the node D, the node C declares
the membership to the node B.
[0127] If the number of undefined ports is larger than "1" at Step
S1008, the branch executes again the process at Step S1006.
[0128] If there is no undefined port at Step S1007 (if all
connection ports of the branch become parent ports), the branch
recognizes itself as the root (Step S1010).
[0129] In the example shown in FIG. 8, the node B whose all
connection ports are parent, is recognized by other nodes as a node
for arbitrating the communication system. Although it is assumed in
this example that the node B is determined as the root, another
node may become a root node if the membership declaration timing of
the node B is faster than that of the node C. Namely, depending
upon the declaration timing, any node has a possibility of becoming
a root. Therefore, the same node is not necessarily a root in the
same network configuration.
[0130] With the above processes, the membership for all nodes is
determined so that the communication system can recognize the
connection state in the form of a hierarchical structure (tree
structure). The parent in the membership is at a higher
hierarchical level and the child is at a lower level.
[0131] FIG. 11 is a flow chart illustrating the details of the
process at Step S905 shown in FIG. 9, i.e., the process of
automatically setting the node ID (bus number and node number) of
each node.
[0132] Referring to FIG. 11, the root permits a node to set a node
ID, the node being connected to a communication port of the root
and having a minimum number among its connection ports (Step
S1101). After all nodes connected to the connection port having the
minimum number are given node IDs, the root performs similar
controls relative to the node connected to the next minimum port
number. In this manner, the root node is given the last node ID.
The node numbers contained in the node IDs are assigned "0", "1",
"2", . . . basically in the order from leafs to branches.
Therefore, the root has the largest node number.
[0133] The permitted node checks whether there is a parent port
(communication port connected to a child node) still not set with
the node ID (Step S1102).
[0134] If there is a parent port still not set with the node ID at
Step S1102, the node permits the node connected to the minimum port
number to set a node ID (Step S1103).
[0135] The node permitted at Step S1103 checks whether there is a
parent port still not set with the node ID (Step S1104).
[0136] If it is checked at Step S1104 that there is a parent port
still not set with the node ID, the permitted node executes again
the process at Step S1103.
[0137] If there is no communication port still not set with the
node ID at Step S1102 or at Step S1104, the permitted node sets its
own node ID (Step S1105). The first node which first permitted the
second node determines that the communication port of the first
node has already been set.
[0138] The node which completed the node ID setting broadcasts a
self ID packet containing its node ID information and its
communication port connection state (Step S1106). The term
"broadcast" means to transmit a communication packet from one node
to all the nodes constituting a communication system. Upon
reception of this self ID packet, each node can recognize the node
ID assigned to each node.
[0139] For example, in the example shown in FIG. 8, the root node B
permits the node A connected to the communication port with the
minimum port number "#1" to set the node ID. The node number of the
node A is therefore set to "No. 0", and the node A broadcasts the
self ID packet containing the node number.
[0140] After the process at Step S1106, the node which set the node
ID checks whether there is a parent node (Step S1107). If there is
a parent node, the parent node again executes the processes
starting from Step S1102 to give a permission to the node still not
set with the node ID.
[0141] If there is no parent node, this node is judged to be the
root. The root checks whether all nodes constituting the
communication system were set with the node IDs (Step S1108).
[0142] If it is judged at Step S1108 that all nodes constituting
the communication system are still not set with the node IDs, the
root permits the node connected to the communication port with the
next minimum port to set the node ID (Step S1101). Thereafter, the
processes starting from Step S1102 are executed.
[0143] If all nodes were set with the node IDs, the root sets its
own node ID (Step S1109). Thereafter, the root broadcasts a self ID
packet (Step S1110) to terminate the node ID setting procedure.
[0144] With the above processes, the communication system can
automatically assign each node with a node ID.
[0145] <Arbitration>
[0146] FIGS. 12A and 12B illustrate arbitration of the 1394
interface. In FIGS. 12A and 12B, a node B is a root, nodes A and C
are branches, and nodes D, E and F are leaves.
[0147] With the 1394 interface, prior to data transmission,
arbitration for a bus use privilege is performed necessarily. With
the 1394 interface, a logical bus type network can be configured in
which a communication packet transmitted to each node is relayed to
another node to allow the communication packet to be transmitted to
all nodes in the network system. Therefore, in order to prevent
collision of communication packets, it is essential to perform
arbitration. With this arbitration, only one node can transmit data
at a time,
[0148] FIG. 12A is a diagram illustrating the case wherein nodes C
and F issue a request for bus use privilege. As arbitration starts,
the nodes C and F issue a bus use privilege request to the parent
node. Upon reception of the request from the node F, the parent
node (i.e., node A) further issues a bus use privilege request to
its parent node (i.e., relays the request from the node F). This
request reaches the root (node B) which performs final
arbitration.
[0149] The root received the bus use privilege request determines
which node can use the bus. This arbitration work can be performed
only by the root node, and the node succeeded the arbitration is
given a bus use privilege. In the example shown in FIG. 12B, the
node C is permitted to use the bus, and the request from the node F
is rejected.
[0150] The root transmits a DP (data prefix) packet to the node
which failed the arbitration to thereby inform the node of a
failure. The rejected node stands by until the next arbitration for
the bus use privilege.
[0151] By controlling the arbitration in the above manner, the
communication system can control the use of the but by each
node.
[0152] <Asynchronous Transmission Mode>
[0153] The asynchronous transmission transmits data asynchronously.
FIG. 13 shows a time sequential transition during the asynchronous
transmission.
[0154] The first subaction gap shown in FIG. 13 indicates an idle
state of the bus. When this idle time reaches a constant value, the
node intending to transmit data judges that the bus can be used,
and executes an arbitration for acquiring the bus.
[0155] If a use permission is obtained by the arbitration, the data
in a packet format is transmitted. After the data transmission, the
node received the asynchronous packet returns back an ack
(reception confirmation return code) or a response packet after a
short ack gap. The ack is constituted of four-bit information and
four-bit check sums including information of a success, failure, or
pending state, and is returned immediately to the transmission
source node.
[0156] FIG. 14 shows an example of the packet format used by the
asynchronous transmission. A communication packet transmitted in
the asynchronous transmission mode is called an asynchronous
packet.
[0157] Referring to FIG. 14, an asynchronous packet includes a
header field 1401, a header CRC 1402, a data field 1403, and a data
CRC 1404. The header field 1401 includes a field 1405 for storing
an object node ID, a field 1406 for storing a source node ID, a
field 1407 for storing a packet format and data for discriminating
between processes to be executed (i.e., transaction code (tcode)),
and other fields.
[0158] The asynchronous transmission is peer-to-peer communications
between its own node and a partner node. A packet transmitted from
the transmission source node is transmitted to each node of the
network. However, the packet transmitted to each node and not
having an address of the node is discarded, so that only one node
having the object node address can read the packet.
[0159] <Isochronous Transmission>
[0160] The isochronous transmission transmits data synchronously.
This mode is suitable particularly for real time data transmission
required for multi media data such as video and audio data.
Although the asynchronous transmission is peer-to-peer
transmission, this isochronous transmission can broadcast a packet
from one transmission source to all other nodes, by using the
broadcast function. The isochronous transmission does not use the
ack (reception confirmation return code).
[0161] FIG. 15 shows a time sequential transition during the
asynchronous transmission. In this embodiment, a communication
packet transmitted during the isochronous transmission mode is
called an isochronous packet.
[0162] Referring to FIG. 15, the isochronous transmission mode is
executed each communication cycle. The communication cycle period
is generally 125 .mu.s. A cycle start packet is transmitted at the
start of each communication cycle. This cycle start packet has a
roll of adjusting time at each node. The cycle start packet is
transmitted to all nodes after a predetermined idle period
(subaction gap) after the completion of each communication cycle.
One communication cycle period is a period from the transmission of
a preceding cycle start packet to the reception of the succeeding
cycle start packet.
[0163] In the example shown in FIG. 15, channels A, B and C
represent bandwidths of different isochronous packets. With the
1394 interface, different channel numbers are assigned in order to
discriminate between a plurality of different isochronous packets.
It is therefore possible to transmit a plurality of isochronous
packets to a plurality of nodes. This channel ID does not indicate
the object node address, but it is only a logical number of
data.
[0164] The iso gap (isochronous gap) shown in FIG. 15 is an idle
period necessary for the recognition of an idle state of the bus
prior to performing the isochronous transmission mode. After this
idle period lapses, a node intending to perform isochronous
transmission judges that the bus is idle and arbitration can be
performed before the transmission.
[0165] The isochronous transmission mode is necessarily performed
at each cycle in order to preserve real time transmission.
[0166] FIG. 16 shows an example of the format of a packet used
during the isochronous transmission mode.
[0167] Referring to FIG. 16, an isochronous packet includes a
header field 1601, a header CRC 1602, a data field 1603 and a data
CRC 1604. The data field 1603 includes a field 1605 for storing
data representative of a data length, a field 1606 for storing data
representative of a channel number of an isochronous packet, a
field 1607 for storing a packet format and data (i.e., transaction
code (tcode)) for discriminating between processes to be executed,
and other fields.
[0168] <Bus Cycle>
[0169] Both the isochronous and asynchronous transmission mode can
be performed in each communication cycle.
[0170] FIG. 17 shows a time sequential transition of both the
isochronous and asynchronous transmissions in one communication
cycle.
[0171] The isochronous transmission mode is performed with a
priority over the asynchronous transmission mode. The reason for
this is that the isochronous transmission can be performed after
the cycle start packet, with a shorter gap length (isochronous gap)
necessary for the isochronous transmission than a gap length
(subaction gap) of the idle period necessary for performing the
asynchronous transmission. The isochronous transmission is
therefore performed with a priority over the asynchronous
transmission.
[0172] Referring to FIG. 17, at the start of the communication
cycle #m, a cycle start packet is transmitted to each node. Each
node performs time adjustment by using this packet.
[0173] After the isochronous gap, a node intending to perform
isochronous transmission transmits an isochronous packet. In the
example shown in FIG. 17, isochronous packets of a channel e, a
channel s and a channel k are transmitted after each isochronous
gap.
[0174] After the isochronous packet is transmitted for a
predetermined time period, each node can transmit the asynchronous
packet. The asynchronous transmission by each node is executed
after the subaction gap. The period while the asynchronous
transmission can be performed, is during the period after the
isochronous transmission and before the time (cycle synch) when the
next cycle start packet is transmitted.
[0175] If it becomes the time (cycle synch) when the next cycle
start packet is transmitted while the asynchronous packet is
transmitted, the asynchronous packet is not forcibly intercepted,
but after the completion thereof, the next cycle start packet is
transmitted. If one communication cycle continues longer than 125
.mu.s, the next communication cycle period is shortened
correspondingly.
[0176] The structure and function of the communication system using
1394 interfaces have been described above.
[0177] <Direct Print System using IEEE 1394
Specifications>
[0178] With reference to FIG. 2, a direct print system using IEEE
1394 specifications will be described.
[0179] In FIG. 2, reference numeral 201 represents a digital VTR
integrated with a camera as a recording/reproducing device capable
of recording/reproducing digital image data of a predetermined
format (e.g., SD-VTR, MPEG) on/from a recording medium. The digital
VTR integrated with a camera 201 can converts digital image data
stored in a recording medium into a packet and transmit it to an
external apparatus in accordance with a predetermined procedure.
Reference numeral 202 represents a printer capable of printing
digital image data reproduced with the digital VTR integrated with
a camera 201, and reference numeral 203 represents a monitor
capable of displaying still and moving images transmitted from the
digital VTR integrated with a camera 201.
[0180] The communication system shown in FIG. 2 is illustrative
only, and the connection state may be changed as desired different
from that shown in FIG. 2, or various other apparatuses may be
connected to this system. Apparatuses connected to this system may
be other electronic apparatuses such as a hard disk, a CD player, a
DVD player, so long as they can conform with IEEE 1394
specifications and can configure a network.
[0181] With reference to FIG. 18, the structure of the
communication system shown in FIG. 2 will be described in
detail.
[0182] In a recording/reproducing device (a digital VTR integrated
with a camera) 201 shown in FIG. 18, reference numeral 4 represents
an image pickup unit, 5 represents an A/D converter, 6 represents
an image processing unit, 7 represents a compression/expansion unit
for performing a compression encoding during recording and an
expansion decoding during reproducing in accordance with a
predetermined algorithm, 8 represents a recording/reproducing unit
for recording/reproducing moving or still images on/from a
recording medium 19 with a recording/reproducing head or the like,
9 represents a system controller having a microcomputer and a
memory for storing predetermined program codes, 10 represents an
operation unit for entering information to control the digital VTR
integrated with a camera 201, 11 represents a D/A converter, 12
represents an EVF (Electric View Finder) used for displaying a
reproduced image or a picked-up image, 13 represents a memory for
temporarily storing non-compression encoded image data of N frames,
14 represents a memory controller for controlling timings of
reading data from, or writing data into, the memory 13, 15
represents a memory for temporarily storing compression encoded
image data of N frames, 16 represents a memory controller for
controlling timings of reading data from, or writing data into, the
memory 15, 17 represents a data selector for selecting outputs of
the memories 13 and 15, 18 represents a 1394 interface for
performing communications in conformity with IEEE 1394
specifications, and 19 represents a recording medium of a magnetic
tape. In the first embodiment, the digital VTR integrated with a
camera using a magnetic tape as its recording medium is used.
Instead a digital camcorder using an optical disk, a solid state
memory and the like may also be used as the recording medium.
[0183] In a printer 202 shown in FIG. 18, reference numeral 19
represents a 1394 interface of the printer 202, 20 represents a
data selector for selecting either control data or image data, 21
represents a decoding unit for decoding image data compression
encoded with a predetermined algorithm, 22 represents an image
processing unit for forming a print image, 23 represents a memory
used by the image processing unit 22 when a print image is formed,
24 represents a printer head, 25 represents a drive for driving the
printer head and feeding a recording sheet, 26 represents a printer
controller for controlling each part of the printer 202, and 27
represents an operation unit for entering information for
controlling the printer.
[0184] In a monitor 203 shown in FIG. 18, reference numeral 61
represents a 1394 interface of the monitor 203, 62 represents an
expansion/decoding unit for expansion decoding video data
compression encoded by a predetermined algorithm, 63 represents a
D/A converter, 64 represents a CRT, 65 represents a system
controller for controlling each part of the monitor 203, and 66
represents an operation unit for entering information for
controlling the monitor 203. In the first embodiment, in addition
to the above components, the monitor 203 is equipped with a circuit
for receiving and displaying a known television signal.
[0185] Next, the operation of each apparatus constituting the
communication system shown in FIG. 2 will be described.
[0186] <Operation of Recording/Reproducing Device 201>
[0187] In a "record mode", an analog image signal (including moving
and still images) picked up with the image pickup unit 4 is
digitalized by the A/D converter 5 and processed by the image
signal processing unit 6. One output (standard television signal of
NTSC format) of the image signal processing unit 6 is converted
into analog signals of the image now being taken by the D/A
converter and displayed by EVF 12. The other output is compression
encoded by the compression/expansion unit 7 in accordance with a
predetermined algorithm and recorded in the recording medium by the
recording/reproducing unit 8. The compression encoding includes a
JPEG format used by digital cameras or the like, a compression
format based on DCT (discrete cosine transform) and VLC (variable
length coding) used by home digital VTRs or the like, an MPEG
format, and the like.
[0188] In a "reproduce mode", the recording/reproducing unit 8
reproduces a desired image stored in the recording medium. In this
case, a desired image is selected in accordance with a user
instruction entered from the operation unit 10, and reproduced
under the control of the system controller 9. If the image data
reproduced by the recording medium is to be transmitted in the
compression state, the reproduced data is stored in the memory
(frame memory) 15. If the image data is to be transmitted in the
non-compression state, the reproduced data is expansion decoded by
the compression/expansion unit 7 and stored in the memory 13. If
the reproduced image data is to be displayed by EVF 12, it is
expanded by the compression/expansion unit 7, converted into analog
signals by the D/A converter 11, and supplied to EVF 12 to display
images.
[0189] Read/write of the frame memories 13 and 15 is controlled by
the memory controllers 14 and 16 under the control of the system
controller 9. The read image data is supplied to the data selector
17. In this case, the data selector 17 is controlled to select one
of the outputs from the frame memories 13 and 15 at a time.
[0190] Although the system controller 9 controls each part of the
recording/reproducing device 201, it can also perform the following
control. Namely, it generates command data for controlling the
printer 202 and monitor 203 and asynchronously transmits the
command to the printer and monitor via the data selector 17 and
1394 interface 18. It also controls each part of the
recording/reproducing device 201 by using various command data
asynchronously transmitted from the printer 202 and monitor 203.
For example, a command data indicating a presence/absence of a
decoder or the type of a decoder asynchronously transmitted from
the printer 202 or monitor 203 is supplied as a request command to
the system controller 9. Thereafter, in accordance with the command
data, it is judged whether image data of either compression or
non-compression is to be transmitted from the recording/reproducing
device 201. In accordance with this judgement, a command is
transmitted to the memory controller 14, 16 to read proper one of
the image data from the frame memory 13, 15.
[0191] The judgement whether image data of either compression or
non-compression is to be transmitted is performed in accordance
with the information of a decoder of the printer 202 or monitor
203. If it is judged from the decoder information that the
compression encoding of the recording/reproducing device 201 can be
decoded, the compression encoded image data is read from the memory
15, whereas if it is judged that the compression encoding cannot be
decoded, the non-compression encoded image data is read from the
memory 13.
[0192] The image data and command data supplied to the data
selector 17 are transmitted by the 1394 interface 18 to the cable
in accordance with the IEEE 1394 specifications, and received by
the printer 202 if the image data is the print still image data, or
by the monitor 203 if the image data is the display moving image
data. The command data is also asynchronously transmitted to a
desired node when necessary. Real time data mainly moving image
data and audio data is isochronously transmitted, whereas command
data is asynchronously transmitted. Among data generally
isochronously transmitted, some data may be asynchronously
transmitted depending upon the transmission conditions or if
asynchronous transmission is preferable.
[0193] <Operation of Printer 202>
[0194] In operation of the printer 202, data input to the 1394
interface 19 is classified into respective types of data by the
data selector 20. Data to be printed such as still image and
compression encoded is expansion decoded by the decoding unit 21
and thereafter output to the image processing unit 22. As described
earlier, the recording/reproducing device 201 transmits data by
selecting either compression encoding or non-compression encoding
so as to have optimum transmission, in accordance with the
previously transmitted information of a presence/absence of a
decoder or the type of a decoder. Therefore, if the transmitted
data was compression encoded, the decoding unit 21 of the printer
202 can expansion decode the received data in a method
corresponding to the compression encoding. If the transmitted data
was non-compression encoded, this case corresponds to either the
case that the printer 202 has no decoding unit 21 or the case that
the printer 202 has the decoding unit 21 which cannot deal with the
compression of the recording/reproducing device 201. In such a
case, the received data is directly supplied to the print image
processing unit 22 without passing through the decoding unit 21. If
not the image data but the command data for the printer 202 is
input, it is not necessary to expansion decode it, so that the
decoding unit 21 is not used.
[0195] For example, print still image data input to the image
processing unit 22 is processed so as to make it suitable for
printing and generate print image data by using the memory 23 whose
read/write is controlled by the printer controller 26. This print
image data is sent to the printer head 24 and printed out. Driving
the head of the printer 202 and feeding a recording sheet are
performed by the driver 25, and the control of the driver 25 and
printer head 24 and other controls are performed by the printer
controller 26.
[0196] The operation unit 27 has a monitor circuit for displaying a
paper feed state, reset state, ink check state, and printer 202
operation state (standby, start, stop), and informs a user of these
states. In accordance with the displayed information, the user
operates upon the operation unit 27 to control each part of the
printer 202.
[0197] Next, if the data input to the 1394 interface 19 is command
data for the printer 202, a notice to this effect is informed from
the data selector 20 to the printer controller 26. The printer
controller 26 then controls each part of the printer 202 so as to
follow the instruction of the command data.
[0198] The printer controller 26 can output information of the type
of a decoder of the decoding unit 21 or the presence/absence of the
decoding unit 21 of the printer 202, and can transmit it
asynchronously as the command data to the recording/reproducing
device 201.
[0199] The expansion decoding of the decoding unit may be, for
example, a JPEG format. Decoding of the JPEG format can be
performed by software. Therefore, by using a JPEG decoding program
file stored in a ROM of the decoding unit 21 or by using a decoding
program transmitted from another node, the decoding unit 21 may
decode the received data by software. For example, if the image
data compression encoded by the JPEG format is transmitted from the
recording/reproducing device 201 to the printer 202, this image
data can be decoded by the printer 202 so that the transmission
efficiency can be improved more than non-compression data is
transmitted. By using decoding through software, the printer 202 is
not necessary to have a decoder, lowering manufacture cost. The
decoding unit 21 may have a JPEG decoding circuit (board) as
hardware.
[0200] As described above, a so-called direct print is performed
without using a management apparatus such as a PC, when still image
data is transmitted from the recording/reproducing device 201 to
the printer 202.
[0201] <Operation of Monitor 203>
[0202] Next, the processes to be performed at the monitor 203 will
be described. Moving image data transmitted from the
recording/reproducing device 201 to the 1394 interface 61 of the
monitor 203 is supplied to the expansion decoding unit 62. The
expansion decoding unit 62 expansion decodes the moving image data
by using an expansion decoding method having a predetermined
algorithm.
[0203] In the monitor 203, in accordance with an instruction input
from the operation unit 66, the system controller 65 controls each
part of the monitor 203.
[0204] The moving image data transmitted to the monitor 203 is
compressed or non-compressed so as to have optimum transmission, in
accordance with the previously transmitted information of a
presence/absence of a decoder or the type of a decoder which the
recording/reproducing device 201 received, similar to the case of
the printer 202. Therefore, even if the received moving image data
is compression encoded data, this received data can be decoded
through expansion decoding having a predetermined algorithm
corresponding to the expansion decoding unit 62 of the monitor
203.
[0205] In displaying the moving image data on CRT 64, if the data
is compressed encoded data, it is expansion decoded by the
expansion decoding unit 62 and thereafter supplied to the D/A
converter 63 to be displayed on CRT 64, whereas if it is
non-compression encoded data, it is directly supplied to the D/A
converter 63 and displayed on CRT 64.
[0206] For example, the expansion decoding unit 62 of the monitor
203 may be a dedicated hardware board capable of performing a
decoding process for an MPEG format for example, or a ROM storing
program codes which perform a decoding process for an MPEG format
or a JPEG format through software. The type or presence/absence of
such a decoder is transmitted from the monitor 203 to the
recording/reproducing device 201.
[0207] With the structure constructed as above, prior to
transmitting the moving or still image data from the
recording/reproducing device 201 to the printer 202 or monitor 203,
the recording/reproducing device 201 can receive the information of
a decoder of the printer 202 or monitor 203 asynchronously
transmitted. Accordingly, in accordance with the performance of the
decoder at an object node, the recording/reproducing device 201
selectively transmits compression encoded image data itself if it
can be decoded, or non-compression image data if the encoded data
cannot be decoded.
[0208] <Transmission Sequence of Image Data>
[0209] Next, with reference to the flow chart of FIG. 19, the
operation of the recording/reproducing device 201 when image data
(including moving and still images) is transmitted, will be
described.
[0210] FIG. 19 illustrates a mode of transmitting image data from
the recording/reproducing device 201 to another apparatus via the
1394 interfaces. First, at Step S1 the recording/reproducing device
201 performs data transmission setting for an object node in
accordance with a user's designation. At Step S2, the
recording/reproducing device 201 asynchronously transmits a command
to an object node, the command including predetermined information
notifying the object node of that transmission will starts soon and
information urging the object node to transmit the information of a
presence/absence, type and the like of a decoder. Upon reception of
the command transmitted at Step S2, the object node asynchronously
transmits to the recording/reproducing device 201 a predetermined
transmission confirmation command data including decoder
information.
[0211] Upon reception of the transmission confirmation command
data, the system controller 9 of the recording/reproducing device
201 checks whether the decoder information was able to receive. If
the decoder information was received and the presence and type of
the decoder was able to identify, the flow advances to Step S4. On
the other hand, the flow advances to Step S6 if the received
command data does not contain the decoder information, if it
contains information indicating that the decoder is not present, or
if the command data is not transmitted from the object node or is
not received until a predetermined time lapse because of a bus
transmission error or asynchronous transmission delay.
[0212] The decoder information contained in the command data
transmitted from the object node to the source node or
recording/reproducing device 201 is used for judging whether image
data to be compressed and stored is transmitted or is
non-compressed and thereafter transmitted. Namely, the decoder
information has a roll of informing the source node of that the
object node wants to receive either compressed data or
non-compressed data. Therefore, if the object node, e.g., monitor
203 already knows the information of the compression scheme used by
the source node or recording/reproducing device 201, a command
requesting to receive either compressed image data or
non-compressed image data may be returned in response to the
command data transmitted at Step S2 from the recording/reproducing
device 201, instead of returning the command data containing the
decoder information of the monitor 203.
[0213] Next, at Step S4 if the type of the decoder judged from the
received decoder information corresponds to the decoder which can
deal with the compression encoding having a predetermined algorithm
used by the compression/expansion unit 7 of the
recording/reproducing device 201, then the recording/reproducing
device 201 judges that the object node can decode image data.
Thereafter, at Step S5 the recording/reproducing device 201
controls an output of the memory 15 in order to isochronously or
asynchronously transmit the compression encoded image data. If it
is judged at Step S4 that the type of the decoder cannot deal with
the compression encoding used by the recording/reproducing device
201 or if the decoder information was not able to receive at Step
S3 (i.e., if it is judged that there is no decoder at the object
node), then at Step S6 the recording/reproducing device 201
expansion decodes the image data. In order to isochronously or
asynchronously transmit non-compressed image data, the
recording/reproducing device 201 controls an output of the memory
13.
[0214] After the output format is set in accordance with the type
of the object node as described above, at Step S7 the user selects
moving images stored in the recording medium 19 in order to print
or display it. The recording/reproducing device 201 reads the
selected moving image. After the image is selected, at Step S8 the
user instructs a transmission of the desired image.
[0215] Next, in accordance with the setting at Step S5 or S6, it is
checked at Step S9 whether the object node has a decoder. If it
has, at Step S10 the compressed image data reproduced from the
recording medium 19 is transmitted. Specifically, in response to
the transmission instruction at Step S8, the system controller 9
and memory controller 16 control an output read from the memory 15.
If the object node has no decoder, at Step S11 non-compressed image
data expanded at the compression/expansion unit 7 is transmitted.
Specifically, in response to the transmission instruction at Step
S8, the system controller 9 and memory controller 16 control an
output read from the memory 13. In this embodiment, a packet of
moving image data is transmitted by the isochronous transmission in
conformity with IEEE 1394 specifications, and a packet of still
image data is transmitted by the asynchronous transmission.
[0216] When desired image data is transmitted at Step S12, it is
checked at Step S13 whether other image data is to be transmitted.
If other image data is selected, the processes at Step S7 and
following Steps are repeated. If other image data is not selected,
the flow advances to Step S14 whereat it is judged whether the
image data transmission mode continues by changing an object node.
If it continues, the processes at Step S1 and following Steps are
repeated. If it is judged at Step S14 that the mode is not
necessary to be continued with a changed an object node, this flow
is terminated. This flow starts from Step S1 in response to a
transmission response of moving or still images.
[0217] As described above, in this embodiment, the
recording/reproducing device 201 acquires information of which
decoding method an object node has, from the object node to which
image data is to be transmitted. If it is judged from the acquired
information that the recording/reproducing device encodes image
data by a procedure corresponding to the decoding method of the
object node, then image data encoded by the corresponding encoding
procedure is transmitted, whereas if it is judged contrarily,
encoded image data is decoded and thereafter transmitted.
Accordingly, even if the source node uses any type of a decoding
method, encoded data corresponding to the decoding method can be
reliably transmitted. If the same encoding and decoding methods are
used by an object node, encoded data can be transmitted and
received so that communications can be speeded up. The capacity of
a memory required for transmission/reception can be reduced if
decoded data is transmitted.
[0218] In the first embodiment, it is judged whether encoded data
reproduced from the recording medium 19 is to be transmitted
directly or after it is decoded, in accordance with the decoding
performance of the object node. The invention is not limited only
thereto. For example, it may be judged whether data still not
stored in the recording medium 19 is to be transmitted directly or
after it is encoded.
[0219] Next, with reference to the flow chart shown in FIG. 20,
another operation will be described in which moving image data
taken with, for example, the digital VTR integrated with a camera
201 is isochronously transmitted and a still image contained in the
moving images is printed with the printer 202.
[0220] In the first embodiment, the decoding unit 21 of the printer
202 does not match the encoding method of a still image generated
by the digital VTR integrated with a camera 201. Therefore, a still
image to be transmitted to the printer 202 from the digital VTR
integrated with a camera 201 is non-compression encoded.
[0221] Also in the first embodiment, the expansion decoding unit 62
of the monitor 203 matches the encoding method of a moving image
generated by the digital VTR integrated with a camera 201.
Therefore, a moving image to be transmitted to the monitor 203 from
the digital VTR integrated with a camera 201 is compression
encoded.
[0222] In the "record mode", in transmitting moving image data to
an external apparatus, a user selects a moving image from a desired
time point with the operation unit 10 and instructs to transmit the
moving image (Step S2001). The moving image data output from the
image signal processing unit 6 is compression encoded in a
predetermined manner by the compression/expansion unit 7, and the
compressed image data is supplied to the memory 15. In parallel
with this operation, of the moving image data output from the image
processing unit 6, still images in the unit of several frames are
supplied to the memory 13 without being compression encoded.
[0223] When the operation state of the digital VTR integrated with
a camera 201 is set to the "reproduce mode", the
recording/reproducing unit 8 selects desired moving images and
reproduces them from the recording medium 19 (Step S2001). The
desired moving images are selected in accordance with various
instructions entered from the operation unit 10, and in accordance
with these instructions, the system controller 9 controls the
reproducing operation of the recording/reproducing unit 8. The
compression encoded moving image data reproduced from the recording
medium 19 is directly supplied to the memory 15. In parallel with
this operation, the moving image data is expanded by the
compression/expansion unit 7, supplied to the D/A converter 11, and
stored in the memory 13 in the unit of several frames.
[0224] The moving image data stored in the memory 15 is read and
supplied to the data selector 17 when necessary in order to
transmit it in real time to the external apparatus, under the
control of the memory controller 16. The still image data stored in
the memory 13 is read and supplied to the data selector 17 when
necessary in order to asynchronously transmit it to the external
apparatus, under the control of the memory controller 14. The read
control by the memory controller 14 is controlled by the system
controller 9 to start in response to an instruction (i.e., transfer
request for still image) from the operation unit 10.
[0225] In the first embodiment, a user instructs to start moving
image communications by using a communication mode start switch
(not shown) or the like mounted on the operation unit 10. In
transmitting a still image contained in the moving image data under
transmission to the printer 202 or the like, a user selects a
desired still image by operating upon the operation unit 10 in a
predetermined operation sequence. In this manner, the still image
is transmitted by being time divisionally multiplexed with the
moving image being isochronously transmitted.
[0226] In the first embodiment, although the system controller 9
controls each process of the digital VTR integrated with a camera
201, it can also perform the following operation. Namely, it
generates a control command for controlling the external apparatus
(e.g., printer 202) connected via the 1394 interface 18 and 1394
serial bus and asynchronously transmitting it to the external
apparatus via its 1394 interface 18. The 1394 interface 18 can
receive control data transmitted from an external apparatus
connected to the serial bus, and in accordance with the control
data, the system controller 9 controls the operation of the digital
VTR integrated with a camera 201. Therefore, for example, it is
possible for the monitor 202 to instruct a transmission of a still
image contained in the moving image at a desired time point from
the digital VTR integrated with a camera 201 to the printer 202, by
using the operation unit 10.
[0227] The data selector 17 selectively outputs one of the encoded
moving image data output from the memory 15, the non-encoded still
image data output from the memory 13, and the control command data
output from the system controller 9, and supplies the selected data
to the 1394 interface 18.
[0228] The 1394 interface 18 transmits information data such as
moving and still images and control data for controlling internal
and external apparatuses, by using a communication method in
conformity with the 1394 serial bus. After an instruction of a
communication start entered from the operation unit, a moving image
taken with the digital VTR integrated with a camera 201 is
isochronously transmitted to a number of undefined external
apparatuses at each predetermined communication cycle (e.g., 125
.mu.s) over a reserved transmission bandwidth (Step S2002).
Specifically, the moving image data in the unit of a predetermined
data amount is converted into an isochronous packet shown in FIG.
16 and broadcast to the communication network.
[0229] Command data for selecting a still image to be transmitted
or controlling the operation of an external apparatus is
transmitted irregularly to an object node designated by the
operation unit 10 or by the external apparatus. For example, in
transmitting and printing still image data at the object node
printer 202 on the 1394 serial bus, a user designates the object
node by operating upon the operation unit 10 in a predetermined
operation sequence to thereby asynchronously transmit the still
image data (Step S2003).
[0230] The still image data input to the 1394 interface 18 is
converted into an asynchronous packet shown in FIG. 14 and
transmitted to the designated object node. In the above manner, the
digital VTR integrated with a camera 201 can transmit in real time
the moving image data to all external apparatuses on the 1394
serial bus and can asynchronously transmit the still image data to
only the designated object node (Step S2004).
[0231] FIG. 21 shows an example of time sequential transition of
moving image and still image data transmitted over the 1394 serial
bus.
[0232] Referring to FIG. 21, ch (channel). a represents moving
image data transmitted in an isochronous transmission mode. A
communication cycle (e.g., 125 .mu.s) of the 1394 serial bus is
partitioned by a cycle start packet necessary for making generally
coincident the values of cycle timers of apparatuses on the 1394
serial bus. After the cycle start packet, there is an isochronous
packet transmission period. The 1394 interface 18 transmits the
moving image data ch. a packetized in accordance with a
predetermined communication protocol, over the transmission
bandwidth. The period after the isochronous transmission and before
the next communication cycle is an asynchronous packet transmission
period. During this period, the 1394 interface 18 transmits an
asynchronous packet (including still image and command data) when
necessary, reliably to a specific object node. In this manner, the
isochronous packet (isochronous communication data) and
asynchronous packet (asynchronous communication data) are time
divisionally multiplexed in each predetermined communication cycle
and transmitted over the 1394 serial bus.
[0233] The digital VTR integrated with a camera 201 of the first
embodiment converts the compression encoded moving image data into
an isochronous packet in conformity with the predetermined
communication protocol, and isochronously transmits it as
illustrated in FIG. 21. The non-compression encoded still image
data contained in the moving image data is asynchronously
transmitted as illustrated in FIG. 21. In this manner, the digital
VTR integrated with a camera 201 can isochronously transmit moving
image data in each predetermined communication cycle period and can
isochronously transmit still image data by time divisionally
multiplexing it with the isochronous transmission. Similarly, the
digital VTR integrated with a camera 201 can asynchronously
transmit a control command for controlling the operation of an
external apparatus on the 1394 serial bus. Namely, the 1394
interface 18 isochronously transmits moving image data in each
predetermined communication cycle period and asynchronously
transmits still image data when necessary by using an idle period
of the predetermined communication cycle period, so that the serial
bus can be efficiently used. The above processes are executed until
the moving image data communication process is terminated (Step
S2005).
[0234] The moving and still image data generated by the digital VTR
integrated with a camera 201 is transmitted to each apparatus on
the 1394 serial bus. The monitor 203 on the 1394 serial bus is
previously set so that it can cover the transmission bandwidth (ch.
a) used by the digital VTR integrated with a camera 201 and can
receive the isochronous packet (containing moving image data) in
the bandwidth. The moving image data contained in the received
isochronous packet is supplied to the expansion decoding unit 62
which performs a decoding process suitable for the received moving
image data. Thereafter, the moving image data is converted into an
analog signal by the D/A converter 63 and displayed on CRT 64. In
this case, the operation unit 66 may be used to transmit a control
command for instructing to print a desired still image, to the
digital VTR integrated with a camera 201. In response to this
control command, the digital VTR integrated with a camera 201
starts transmitting the still image.
[0235] The 1394 interface 19 of the printer 202 receives an
asynchronous packet (containing still image or control command)
transmitted from the digital VTR integrated with a camera 201, and
supplies the received data to the data selector 20. The data
selector 20 supplies the received data to the printer controller 26
if it is a control command, or to the image processing unit 28 if
it is a still image. The image processing unit 28 processes the
still image so as to make it suitable for printing, and thereafter
the processed still image is printed.
[0236] The printer 202 of the first embodiment is configured to be
able to print a non-compression encoded and asynchronously
transmitted still image. Therefore, even if a printer cannot deal
with the encoding method used by the digital VTR integrated with a
camera 201, a high quality image can be printed with a simple
system configuration.
[0237] The digital VTR integrated with a camera 201 of the first
embodiment can transmit moving image data taken therewith to
display it on the monitor 203. A user can select a still image to
be printed, while viewing the moving image displayed on the monitor
203. In accordance with this selection, the digital VTR integrated
with a camera 201 asynchronously transmits a desired still image
while transmitting the moving image in real time. In other words,
the digital VTR integrated with a camera 201 can transmit time
divisionally both the moving and still images.
[0238] As described above, according to the first embodiment, if a
source node apparatus uses an encoding method corresponding to the
decoding method at an object node apparatus, the source node can
transmit image information encoded by this encoding method. If the
source node apparatus is not provided with an encoding method
corresponding to the decoding method at an object node apparatus,
the source node can transmit decoded image information. In this
manner, the use efficiency of a communication transmission path can
be improved.
[0239] The digital VTR integrated with a camera 201 of the first
embodiment can broadcast in real time compression encoded or
non-compression encoded moving image information in accordance with
the decoding performance of an object node. Similarly, compression
encoded or non-compression encoded still image information can be
transmitted reliably only to an object node, in accordance with the
decoding performance of the object node.
[0240] The communication system of the first embodiment can not
only select still image information contained in moving image
information without using an editing apparatus such as PC, but also
print the still image information with ease and quickly, without
imparting unnecessary load on other apparatuses.
[0241] 2. Second Embodiment
[0242] In the first embodiment, compression encoded moving images
are transmitted in real time by the isochronous transmission, and
non-compression encoded still images are transmitted asynchronously
by the asynchronous transmission.
[0243] In the second embodiment, compression encoded moving image
is transmitted by the isochronous transmission, and a plurality
frame of non-compression encoded still images are transmitted
sequentially by the isochronous transmission.
[0244] In the second embodiment, the processing units having
similar operations and functions to those of the first embodiment
are represented by using identical reference numerals, and the
description thereof is omitted.
[0245] With reference to FIG. 22, the structure of a communication
system of the second embodiment will be described.
[0246] In FIG. 22, the structures of a digital VTR integrated with
a camera 201 and a printer 202 are similar to those of the first
embodiment. A monitor 204 has a selector 67 and an adder 68 in
addition to the structure of the monitor 203 of the first
embodiment.
[0247] With reference to the flow chart shown in FIG. 23, an
operation will be described in which moving image data taken with,
for example, the digital VTR integrated with a camera 201 is
isochronously transmitted and a still image contained in the moving
images is printed with the printer 202.
[0248] In the second embodiment, the decoding unit 21 of the
printer 202 does not match the encoding method of a still image
generated by the digital VTR integrated with a camera 201.
Therefore, similar to the first embodiment, a still image to be
transmitted to the printer 202 from the digital VTR integrated with
a camera 201 is non-compression encoded.
[0249] Also in the second embodiment, the expansion decoding unit
62 of the monitor 203 matches the encoding method of a moving image
generated by the digital VTR integrated with a camera 201.
Therefore, a moving image to be transmitted to the monitor 204 from
the digital VTR integrated with a camera 201 is compression
encoded.
[0250] A user selects a moving image from a desired time point with
the operation unit 10 of the digital VTR integrated with a camera
201 (Step S2301).
[0251] The compression encoded moving image stored in the memory 15
is read so that it can be transmitted at each predetermined
communication cycle (e.g., 125 .mu.s) after a communication start
instruction from the operation unit 10 (Step S2302).
[0252] The non-compression still image stored in the memory 13 is
read in response to an instruction from the operation unit 10 or an
external apparatus (Step S2303).
[0253] The still and moving image data of a predetermined data
amount read under the control of the memory controllers 14 and 16
is alternately supplied via the data selector 17 to the 1394
interface 18. The 1394 interface 18 converts the still and moving
image data input in the unit of the predetermined data amount into
isochronous packets and isochronously transmits them to the printer
202 and monitor 204 (Step S2304).
[0254] In the second embodiment, a plurality frame of still images
are isochronously transmitted. Therefore, the monitor 204 and
printer 202 on the communication network can receive a plurality of
still images transmitted from the digital VTR integrated with a
camera 201 generally at the same time and a desired still image can
be displayed or printed at respective apparatuses.
[0255] The command data for controlling the operation of an
external apparatus is irregularly and asynchronously transmitted to
an object node designated by the operation unit 10 or by the
external apparatus, similar to the first embodiment.
[0256] FIG. 24 shows an example of time sequential transition of
moving image and still image data transmitted over the 1394 serial
bus.
[0257] Referring to FIG. 24, ch (channel). a represents moving
image data packetized in accordance with the isochronous
transmission method. Similarly, ch. b represents still image data
packetized in accordance with the isochronous transmission
method.
[0258] After the cycle start packet is transmitted, the moving
image data and a plurality frame of still image data packetized in
accordance with the predetermined communication protocol are
transmitted via the 1394 interface over the transmission bandwidths
of ch. a and ch. b. During the period after the isochronous
transmission and before the next communication cycle, the 1394
interface 18 transmits an asynchronous packet (including command
data) when necessary. In this manner, the isochronous packet
(isochronous communication data) and asynchronous packet
(asynchronous communication data) are time divisionally multiplexed
in each predetermined communication cycle and transmitted over the
1394 serial bus.
[0259] The above processes are executed until the moving image data
communication process is terminated (Step S2305).
[0260] In addition, in the second embodiment, the monitor 204 is
previously set so that it can cover the transmission bandwidths
(ch. a, ch. b) used by the digital VTR integrated with a camera 201
and can receive the moving and still image data isochronously
transmitted from the digital VTR integrated with a camera 201.
[0261] FIG. 25 is a diagram showing an example of a display screen
of the monitor 204. In FIG. 25, reference numeral 2501 represents a
moving image display area for displaying moving images, reference
numeral 2502 represents a still image display area for displaying a
still image when necessary, and reference numeral 2503 represents
an operation switch for instructing to display a desired still
image contained in the displayed moving image.
[0262] The selector 67 of the monitor 204 selects either the moving
or still image received via the 1394 interface 61 and supplies the
selected image to the succeeding stage. The moving image data
selectively output from the selector 67 is supplied to the
expansion decoding unit 62 whereat the moving image data is
expansion decoded and then supplied to the adder 68. On the other
hand, a plurality frame of still image data selectively output from
the selector 67 is directly supplied to the adder 68, because the
non-compression encoded still image data is not necessary to be
expansion decoded. The adder 68 adds the still image data to the
moving image to synthesize them to display the still image in the
still image display area in the moving image display area. An
output of the adder 68 is supplied to the D/A converter 63 to
display both the moving and still images on CRT 64 of the monitor
204.
[0263] With the structure constructed as above, a user can view
both the moving and still images on the monitor 204. The user can
therefore confirm the still image to be printed, on the monitor 204
together with the associated moving image.
[0264] Similar to the first embodiment, the printer 202 of the
second embodiment is configured to be able to receive and print a
non-compression encoded still image data. Therefore, even if a
printer cannot deal with the encoding method used by the digital
VTR integrated with a camera 201, a high quality image can be
printed with a simple system configuration.
[0265] As described above, according to the second embodiment of
the invention, if a source node apparatus uses an encoding method
corresponding to the decoding method at an object node apparatus,
the source node can transmit image information encoded by this
encoding method. If the source node apparatus is not provided with
an encoding method corresponding to the decoding method at an
object node apparatus, the source node can transmit decoded image
information. In this manner, the use efficiency of a communication
transmission path can be improved.
[0266] The digital VTR integrated with a camera 201 of the second
embodiment can broadcast in real time compression encoded or
non-compression encoded moving images in accordance with the
decoding performance of an object node. Similarly, a plurality
frame of compression encoded or non-compression encoded still
images can be sequentially broadcast, in accordance with the
decoding performance of the object node. Accordingly, the same
still image can be transmitted generally at the same time to a
plurality of apparatuses.
[0267] The communication system of the second embodiment can not
only select a still image contained in moving images without using
an editing apparatus such as PC, but also print the still image
with ease and quickly, without imparting unnecessary load on other
apparatuses.
[0268] 3. Third Embodiment
[0269] In the first and second embodiments, if a source node
apparatus uses an encoding method corresponding to the decoding
method at an object node apparatus, image information (including
moving and still images) encoded by this encoding method is
transmitted either by the isochronous or asynchronous
transmission.
[0270] In the third embodiment, a source node apparatus transmits
in advance decode program information realizing the decoding method
corresponding to the encoding method of the source node apparatus,
to an object node apparatus. In accordance with the decode program
information, the object node apparatus decodes the image
information asynchronously transmitted from the source node
apparatus. A communication system realizing this will be
described.
[0271] In the third embodiment, the processing units having similar
operations and functions to those of the first and second
embodiments are represented by using identical reference numerals,
and the description thereof is omitted.
[0272] With reference to FIGS. 26 and 27, the structure of a
communication system of the third embodiment will be described.
[0273] FIG. 26 is a schematic diagram showing the structure of the
communication system of the third embodiment. Referring to FIG. 26,
a recording/reproducing device (e.g., digital VTR integrated with a
camera) 205 and a printer 206 are directly connected by an 1394
interface. Namely, the apparatuses are connected in peer-to-peer.
In this communication system, the printer 206 prints image data
(still image) transmitted from the recording/reproducing device
205. The recording/reproducing device 205 and printer 206 have
partially the same structures as those of the first embodiment.
[0274] FIG. 27 is a block diagram showing the detailed structures
of the recording/reproducing device 205 and printer 206 of the
third embodiment. With reference to FIG. 27, the structures of the
recording/reproducing device 205 and printer 206 of the third
embodiment different from the first embodiment will be
described.
[0275] In the recording/reproducing device 205 shown in FIG. 27, a
ROM 74 stores program codes realizing an expansion decoding method
(e.g., MPEG, JPEG, DV (digital video), and the like) corresponding
to a compression encoding method used by the compression encoding
unit 7. A read control unit 73 operates to read the decode program
information constituted of program codes when necessary, and to
transmit it via the data selector 17, 1394 interface 18 to an
external apparatus.
[0276] The decode program information is transmitted by the
asynchronous transmission, or in some case, by the isochronous
transmission. The transmission timing is set to a time before image
data is transferred, or may be in one communication cycle together
with image data transmission.
[0277] Although the recording/reproducing device 205 of the third
embodiment uses an integrated one compression encoding method for
all image data to be stored, another method may be used. For
example, a plurality of compression encoding methods may be
selectively used in the unit of an optional data amount or an
optional time. In this case, ROM 74 stores decode program
information corresponding to a plurality of decoding methods. The
recording/reproducing device 205 transmits the decode program
information to object node apparatuses in a predetermined
order.
[0278] In order to decode image data, the printer 206 receives
decode program information transmitted before the image data or in
parallel with the image data, and stores it in an entirely or
partially rewritable memory 71. The received compression encoded
data is decoded by the decoding unit 72 by using the decode program
information stored in the memory 71.
[0279] The memory 71 can store decode program information
corresponding to an apparatus from which compression encoded data
is transmitted. The decoding unit 72 can function as a plurality
type of decoders, by using the memory 71. The decoding unit 72 may
be structured so that it cannot operate as a decoder unless it
receive decode program information from another apparatus, or a
predetermined decode program may be stored in a partial area of the
memory 71.
[0280] Compatibility of the transmitted/received decode program
information is required between the recording/reproducing device
205 and printer 206. To this end, the decoding unit 72 is
previously standardized and ROM 74 stores the decode program
information written in accordance with the standards.
Alternatively, only a method of writing the decode program
information may be standardized, and the decoding unit 72 analyzes
and executes the standardized decode program information.
[0281] With the structure constructed as above, compression encoded
image data can be transmitted even if it does not match the
decoding performance of the printer 206, and therefore a
transmission efficiency thereof is better than that of
non-compression encoded data.
[0282] In the third embodiment, time bomb data may be added to the
decode program information transmitted to the printer 206 in order
to automatically erase the decode program information after the
print operation of a designated circuit is completed or after a
predetermined time lapse. Such a function may be provided to the
printer 206 itself, e.g., the printer controller 26. Furthermore,
command data for erasing the decode program information may be
transmitted from the recording/reproducing device 205, upon
reception of a completion notice of the print operation.
[0283] FIG. 28 is a flow chart illustrating the operation of the
recording/reproducing device 205 according to the third
embodiment.
[0284] First, at Step S21 a user designates an object node
apparatus. In this embodiment, the printer 206 is designated. In
response to this designation, transmission setting is
performed.
[0285] Next, the user selects image data (still image) to be
printed, from the images stored in the recording medium. At Step
S22, the recording/reproducing device 205 reads the selected image.
After this selected image read operation, at Step S23 the user is
urged to issue a transmission instruction for the desired
image.
[0286] It is judged at Step S24 whether decode program information
necessary for decoding the image data given the transmission
instruction is required to be transmitted to an object node
apparatus (in this case, printer 206). If required, i.e., if it is
judged that the decoding unit 72 of the printer 206 can decode
compression encoded image data by using the decode program
information, then at Step S25 necessary decode program information
is read from ROM 74 and transmitted to the printer 206.
[0287] The printer 206 stores the received decode program
information in the memory 71.
[0288] If it is judged at Step S24 that transmission is not
necessary, i.e., if the object node printer 206 has already
necessary decode program information or if the necessary decode
program transmitted in the past is being stored in the memory 71,
then the decode program information is not transmitted and the
image data starts being transmitted.
[0289] The information used for judging whether decode program
information is required to be transmitted to the printer 206 can be
acquired by returning from the printer 202, in response to a
request from the recording/reproducing device 205, information of
the decode program information possessed by the printer 202.
[0290] Next, at Step S26 the compression encoded image data given
the transmission instruction is read from the recording medium 19,
output to the memory 15 and transmitted to the printer 206.
[0291] Upon reception of the compression encoded data, the printer
decodes it in accordance with the already stored decode program
information to start the printing operation of the image data. If
the decode program information is not still transmitted, the encode
data starts being decoded after the transmission completion.
[0292] At Step S27, after the desired image data is transmitted, a
predetermined process necessary for the transmission completion is
performed. It is checked at Step S28 whether other image data is to
be transmitted. If other image data is selected, the processes at
Step S22 and following Steps are repeated. If other image data is
not selected, the flow is terminated. This flow starts from Step
S21 at any time in response to a transmission request for image
data.
[0293] In the third embodiment, although compression encoded image
information transmitted from the recording/reproducing device 205
to the printer 206 is a still image, the invention is not limited
only thereto. For example, if the recording/reproducing device 205
is connected to a display unit such as a monitor 203, 204,
compression encoded moving images may be transmitted. In this case,
the display unit is required to have components similar to the
memory 71 and decoding unit 72 of the printer 206.
[0294] In the third embodiment, although the transmission method
for a still image is the asynchronous transmission similar to the
first embodiment, the isochronous transmission may be used similar
to the second embodiment. The latter case is convenient if a
plurality of still images are sequentially transmitted or the same
moving image is transmitted to a plurality of apparatuses.
[0295] As above, according to the third embodiment, a source node
apparatus transmits in advance decode program information realizing
a decoding method corresponding to the encoding method to be used
by the source node apparatus, to an object node apparatus.
Accordingly, image information (including moving and still images)
to be transmitted to and from each apparatus is always compression
encoded image data so that the use efficiency of a communication
transmission path can be improved. Furthermore, the capacity of a
memory for storing received image information can be reduced.
[0296] Irrespective of the type of a decoding method at an object
node, the recording/reproducing device 205 of the third embodiment
can transmit compression encoded still image data only to a
designated object node apparatus, when necessary. Furthermore, the
same still image can be transmitted generally at the same time to a
plurality of apparatuses.
[0297] The communication system of the third embodiment can print a
selected still image with ease and rapidly without using an editing
apparatus such as PC.
[0298] 4. Fourth Embodiment
[0299] In the third embodiment, an object node apparatus matches
decode program information to be transmitted from a source node
apparatus.
[0300] In the fourth embodiment, in accordance with the decoding
performance at an object node apparatus, a source node apparatus
transmits encoded image information, non-encoded image information,
or encoded image information and decode program information. This
case of the fourth embodiment will be described hereinunder.
[0301] In the fourth embodiment, the processing units having
similar operations and functions to those of the first to third
embodiments are represented by using identical reference numerals,
and the description thereof is omitted.
[0302] With reference to FIGS. 26 and 27, the structure of a
communication system of the fourth embodiment will be
described.
[0303] Referring to FIG. 26, the recording/reproducing device 205
requests the printer 206 for the decoding performance (hereinafter
called decode information) of the printer 206. If it is judged from
the decode information that the memory 71 is storing decode program
information corresponding to the encoding method to be used by the
recording/reproducing device 205, then the system controller 9
controls the memory controller 16 to read desired image information
(compression encoded moving or still image) from the memory 15. The
image information read from the memory is transmitted by the
isochronous transmission if it is a moving image, or by the
asynchronous transmission if it is a still image.
[0304] If it is judged from the decode information that although a
decoding process using the decode program information is possible,
the memory 71 does not store decode program information
corresponding to the encoding method to be used by the
recording/reproducing device 205, then the system controller 9
controls the read control unit 73 to asynchronously transmit the
decode program information stored in the memory 74. Thereafter, the
system controller 9 controls the memory controller 16 to read
desired image information (compression encoded moving or still
image) from the memory 15. The image information read from the
memory is transmitted by the isochronous transmission if it is a
moving image, or by the asynchronous transmission if it is a still
image.
[0305] If it is judged from the decode information that a decoding
process corresponding to the encoding method to be used by the
recording/reproducing device 205 is not possible and that a
decoding process using the decode program information is not
serviceable, then the system controller 9 controls the memory
controller 14 to read desired image information (compression
encoded moving or still image) from the memory 13. The image
information read from the memory 14 is transmitted by the
isochronous transmission if it is a moving image, or by the
asynchronous transmission if it is a still image.
[0306] With the structure constructed as above, the
recording/reproducing device 205 can transmit compression encoded
image information as much as possible so that the transmission
efficiency is better than that of non-compression encoded image
information. It is also convenient since non-compression encoded
image information can be transmitted even if compression encoded
image information cannot be transmitted.
[0307] FIG. 29 is a flow chart illustrating the operation of the
recording/reproducing device 205 of the fourth embodiment.
[0308] At Step S31, as a user designates an object node apparatus
(e.g., printer 206), and the recording/reproducing device 205
performs transmission setting corresponding to the designation. At
Step S32 the recording/reproducing device 205 asynchronously
transmits a command requesting decoder information (information of
a presence/absence, type, configuration and the like of the decoder
of the printer 205), by using the 1394 bus. Upon reception of the
command issued at Step S32, the printer 206 asynchronously
transmits predetermined transmission confirmation command data
including decoder information to the recording/reproducing device
205.
[0309] At Step S33 the system controller 9 of the
recording/reproducing device 205 judges whether the decoder
information has been received. If received, the flow advances to
Step S34.
[0310] If the printer 206 has no decoder function or it cannot
transmit decoder information, if the command including decode
information is not returned, or if the command is not received even
after a predetermined time lapse because of transmission error on
the bus or asynchronous transmission delay, then the
recording/reproducing device 205 executes Step S40 in order to
transmit only non-compression encoded data.
[0311] Next, at Step S34 the encoding performance of the printer
206 is checked from the decoder information. If it is judged that
the printer 206 can deal with all encoding methods to be used by
the recording/reproducing device 205, Step S35 is executed. If it
is judged that compression encoded data can be decoded if
predetermined decode program information is transmitted, Step S45
is executed. If compression encoded data cannot be decoded because
the printer 206 cannot process the decode program information,
cannot deal with the encoding method to be used by the
recording/reproducing device 205, or has no decoding means, or
because of other reasons, then Step S40 is executed.
[0312] The decode information transmitted from the printer 206 to
the recording/reproducing device 205 is used for selecting either a
mode of transmitting compression encoded image data itself, a mode
of transmitting non-compression encoded image data, or a mode of
transmitting compression encoded image data together with the
decode program information. The decode information has a roll of
judging which transmission mode the printer 206 requests. If
predetermined information is previously notified between nodes, the
decode information in the Step 32 can be used as a command for
requesting compression encoded data transmission, non-compression
encoded data transmission, or decode program information
transmission.
[0313] If the decoding unit 72 of the printer 206 can deal with any
compression encoding method to be used by the recording/reproducing
device 205, Step S35 and following Steps are executed.
[0314] At Step S35 a user selects desired image data (still image)
from the moving image stored in the recording medium 19, and the
recording/reproducing device 205 performs a read operation for the
selected image data. At Step S36 the user instructs to transmit the
selected image. At Step S37, in order to transmit the designated
image data in the form of compression encoded image data, the
designated image data is reproduced from the recording medium 19
and asynchronously transmitted to the printer 206 via the frame
memory 15. In accordance with a predetermined operation sequence,
the printer 206 decodes the image data and starts the print
operation.
[0315] When the desired image data is transmitted at Step S38, it
is judged at Step S39 whether other image data is to be
transmitted. If to be transmitted, Step S35 and following Steps are
repeated, whereas if not to be transmitted, the flow
terminates.
[0316] If the image data cannot be decoded because of the
configuration of the printer 206 or the like, non-compression
encoded data is always transmitted. In this case, the
recording/reproducing device 205 performs Step S40 and following
Steps.
[0317] At Step S40 a user selects desired image data (still image)
from the moving image stored in the recording medium 19, and the
recording/reproducing device 205 performs a read operation of the
selected image data. At Step S41 the user instructs to transmit the
selected image. At Step S42, the designated image data is converted
into non-compression encoded data by the compression/expansion unit
7 and asynchronously transmitted to the printer 206 via the frame
memory 13. In accordance with a predetermined operation sequence,
the printer 206 decodes the image data and starts the print
operation.
[0318] When the desired image data is transmitted at Step S43, it
is judged at Step S44 whether other image data is to be
transmitted. If to be transmitted, Step S40 and following Steps are
repeated, whereas if not to be transmitted, the flow
terminates.
[0319] If the decoding unit 72 of the printer 206 can decode
compression encoded data by using predetermined decode program
information, Step S45 and following Steps are executed in order to
transmit the decode program information and compression encoded
data.
[0320] At Step S45 a user selects desired image data (still image)
from the moving image stored in the recording medium 19, and the
recording/reproducing device 205 performs a read operation of the
selected image data. At Step S46 the user instructs to transmit the
selected image.
[0321] At Step S47 it is judged whether predetermined decode
program information is to be transmitted to the object node printer
206 to decode the image data. If to be transmitted, at Step S48
necessary decode program information is read from ROM 47 and
asynchronously (or isochronously) transmitted to the printer 206.
The printer 206 stores the received decode program information in
the memory 71. The decoding unit 72 performs a decoding process by
using the memory 71.
[0322] If it is judged at Step S47 that it is not necessary to
transmit the decode program information, because the printer 206
has already hardware or software decoding means or the necessary
decode program information has already been stored in the memory
71, then the decode program information is not transmitted and the
image data is transmitted.
[0323] At Step S49, the desired image data in the form of
compression encoded data is read from the memory 16 and
asynchronously transmitted to the printer 206. In accordance with a
predetermined operation sequence, the printer 206 decodes the
transmitted image data by using the transmitted decode program
information and starts the print operation.
[0324] When the desired image data is transmitted at Step S50, it
is judged at Step S51 whether other image data is to be
transmitted. If to be transmitted, Step S45 and following Steps are
repeated, whereas if not to be transmitted, the flow
terminates.
[0325] After the process at Step S39, S44, or S51, in response to a
request for image data transmission, the flow returns to Step S31
to repeat this flow.
[0326] In the fourth embodiment, although image information
transmitted from the recording/reproducing device 205 to the
printer 206 is a still image, the invention is not limited only
thereto. For example, if the recording/reproducing device 205 is
connected to a display unit such as a monitor 203, 204, compression
encoded or non-compression encoded moving images may be
transmitted. In this case, the display unit is required to have
components similar to the memory 71 and decoding unit 72 of the
printer 206. Furthermore, if a plurality frame of still images are
to be sequentially transmitted, these still images may be
isochronously transmitted.
[0327] As above, according to the fourth embodiment, a source node
apparatus selects a suitable mode in accordance with the decoding
performance of an object node apparatus, from a mode of
transmitting encoded image information, a mode of transmitting
non-encoded image information and a mode of transmitted encoded
image information and decode program information. Accordingly,
image information (including moving and still images) to be
transmitted to and from each apparatus is compression encoded in
accordance with the decoding performance of an object node
apparatus so that the use efficiency of a communication
transmission path can be improved. Furthermore, the capacity of a
memory for storing compression encoded image information received
at an object node apparatus, can be reduced.
[0328] The recording/reproducing device 205 of the fourth
embodiment can transmit compression encoded still image data only
to a designated object node apparatus, when necessary, in
accordance with the decoding performance at an object node
apparatus.
[0329] The communication system of the fourth embodiment can print
compression encoded image information with ease and rapidly without
using an editing apparatus such as PC, in accordance with the
decoding performance of an object node apparatus.
[0330] 5. Other Embodiments
[0331] The process sequence of each apparatus of the communication
system of the first to fourth embodiments can be realized by
software.
[0332] For example, the embodiments of the present invention may be
realized, by configuring that a storage medium storing program
codes of software realizing the functions of each embodiment is
supplied to a controller (including a microcomputer) of the system
or apparatus of each embodiment, or by configuring that a
controller of the system or apparatus of each embodiment reads the
program codes stored in the storage medium and controls the system
or apparatus so as to realize the functions of each embodiment.
[0333] For example, the program codes realizing the processes and
functions of the first and second embodiments shown in FIG. 19, the
third embodiment shown in FIG. 28 and the fourth embodiment shown
in FIG. 29 are stored in storage media of the system controller 9
shown in FIGS. 18, 22 and 27. The system controller 9 itself reads
the program codes to operate each process unit of the
recording/reproducing devices 201 and 205 shown in FIGS. 18, 22 and
27 to realize the functions of the embodiments.
[0334] In this case, the program codes themselves read from a
storage medium realize the functions of the embodiments. Therefore,
the storage medium storing the program codes constitutes the
present invention.
[0335] The storage medium storing such program codes may be a
floppy disk, a hard disk, an optical disk, a magneto-optical disk,
a CD-ROM, a CD-R, a magnetic tape, a non-volatile memory card, and
a ROM.
[0336] Obviously, the invention includes the case wherein the
embodiment functions are realized by an OS (operating system),
application software or the like which controls the system or
apparatus of the embodiments in accordance with instructions of the
program codes read from a storage medium.
[0337] Obviously, the invention includes the case wherein the
embodiment functions are realized by writing the program codes read
from a storage medium into a memory of an expansion board or unit
connected to a controller which controls the operation of the
system or apparatus of the embodiments in accordance with the
program codes.
[0338] The invention may be embodied in other specific forms
without departing from the spirit or essential characteristics
thereof.
[0339] For example, in the above embodiments, although image
information recorded in the recording medium 19 is encoded or
non-encoded and transmitted, the invention is not limited thereto,
but image information picked up with the image pickup unit 4 and
generated by the image signal processing unit 6 may be encoded or
non-encoded and transmitted.
[0340] In the above embodiments, a digital VTR integrated with a
camera and dealing moving and still images is used as an example of
the recording/reproducing device 201, 205. Other
recording/reproducing devices may also be used which can
record/reproduce digital data (e.g., audio data) such as moving
images desired to the transmitted in real time and digital data
(e.g., file data) such as still images not desired to be
transmitted in real time. These devices may be storage devices, DVD
(digital video disc) players, CD-ROM players and the like.
[0341] In the above embodiments, although the communication system
is configured by using digital interfaces in conformity with IEEE
1394 specifications, the invention is not limited thereto. For
example, communication interfaces using two communication
transmissions corresponding to isochronous and asynchronous
transmissions may be used.
[0342] Therefore, the above-mentioned embodiments are merely
examples in all respects, and must not be construed to limit the
invention.
[0343] The scope of the present invention is defined by the scope
of the appended claims, and is not limited at all by the specific
descriptions of the specification. Furthermore, all the
modifications and changes belonging to equivalents of the claims
are considered to fall within the scope of the present
invention.
* * * * *