Multiplex communications – Communication techniques for information carried in plural... – Combining or distributing information via time channels
Reexamination Certificate
1997-11-07
2001-04-03
Nguyen, Chau (Department: 2739)
Multiplex communications
Communication techniques for information carried in plural...
Combining or distributing information via time channels
C348S423100, C375S240280
Reexamination Certificate
active
06212208
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to methods and apparatuses for coding and multiplexing multimedia data, and record media containing programs for coding and multiplexing multimedia data. More specifically, the invention relates to those for generating multimedia data coded and multiplexed information in which multimedia data including video and audio data have been subjected to digitization, coding, and time division multiplexing by a computer system having an operating system.
BACKGROUND OF THE INVENTION
With the development of digital technology in recent years, multimedia data which have conventionally been processed only in analog form, for example, information including video and audio data, can be converted to digital information by digitization, compressive coding, and multiplexing, and the digital information can be used for recording and transmission. Multimedia data coded and multiplexed information so generated, for example, video/audio coded and multiplexed information, is called “system stream”. Usually, a system stream is a one-dimensional array in which digitized, coded, and compressed video information and digitized, coded, and compressed audio information are alternately placed in prescribed units.
FIG. 27
shows an example of video/audio coded and multiplexed information. In the figure, reference numeral
2101
denotes a video sequence header showing that coded video information
2101
follows the header. When the coded (compressed) video information
2102
is subjected to inverse coding (expansion), an image having a reproduction time is generated. Reference numeral
2103
denotes an audio sequence header showing that coded audio information
2104
follows the header. When the coded (compressed) audio information
2104
is subjected to inverse coding (expansion), a voice having a reproduction time is generated. This audio/video coded and multiplexed information is also called “time-division-multiplexed information”, and processes for generating this information are a coding process and a multiplexing process.
In an apparatus for reproducing the audio/video coded and multiplexed information, for video/audio synchronization at reproduction, video information and audio information to be reproduced synchronously are accumulated in a buffer and, when the video information and the audio information are completely stored in the buffer, they are decoded and reproduced. Since the capacity (size) of an internal buffer in a reproduction apparatus is limited, the coded video information
2102
and the coded audio information
2104
shown in
FIG. 27
must be alternately arranged by quantities within a range allowed by the size of the internal buffer. More specifically, when the size of internal buffer is equivalent to 0.1 sec, the coded video information
2102
and the coded audio information
2104
must be alternately arranged in units that make the reproduction time not longer than 0.1 sec. Depending on the structure of the reproduction apparatus, there is a case where audio information and video information must be arranged alternately by quantities that make the video reproduction time and the audio reproduction time equal to each other.
A description is now given of a conventional apparatus for coding video/audio information and outputting video/audio coded and multiplexed information as mentioned above.
FIG. 26
is a block diagram illustrating a video/audio coding and multiplexing apparatus according to the prior art. With reference to
FIG. 26
, this apparatus is provided with an image/voice input means
2001
, an audio capture means
2002
, an audio coding means
2003
, a coded audio storage means
2004
, a video capture means
2005
, a video coding means
2006
, a coded video storage means
2007
, and a file management means
2008
.
The image/voice input means
2001
is implemented by a video camera or the like. This means
2001
receives image and voice, and outputs analog video information and analog audio information, separately. The audio capture means
2002
receives the analog audio information output from the input means
2001
, and outputs digital audio information comprising discrete digital data. The audio coding means
2003
receives the digital audio information output from the audio capture means
2002
, compresses the information by coding it excluding redundant information, and outputs coded audio information per unit time. In this case, the unit time is 0.1 sec. The coded audio storage means
2004
adds an audio sequence header to the coded audio information output from the audio coding means
2003
, and outputs it to the file management means
2008
. The video capture means
2005
receives the analog video information output from the image/voice input means
2001
, and outputs digital video information comprising discrete digital data. The digital video information is composed of plural pieces of still picture information, each showing a still picture per unit time. The video coding means
2006
receives the digital video information output from the video capture means
2005
, compresses the information by coding it excluding redundant information, and outputs coded video information. In this example, coded video information is output in units of individual still pictures. Since a still picture exists every {fraction (1/30)} sec, the unit time for outputting the coded video data is {fraction (1/30)} sec. The coded video storage means
2007
adds a video sequence header to the coded video information output from the video coding means
2006
, and outputs it to the file management means. The file management means
2008
writes the input audio and video information in a file in a storage unit.
FIG. 27
shows video/audio coded and multiplexed information obtained by the conventional video/audio coding and multiplexing apparatus shown in FIG.
26
. As shown in
FIG. 27
, for the reproduction process performed later, video information and audio information are arranged alternately by quantities that make the video reproduction time and the audio reproduction time equal to each other, and the reproduction time is not longer than 0.1 sec.
FIG. 28
is a diagram for explaining the operation of the video/audio cording and multiplexing apparatus shown in
FIG. 26
, with respect to the flow of data.
In
FIG. 28
, the same reference numerals as those shown in
FIG. 26
designate the same or corresponding parts, and a video camera is employed as the image/voice input means
2001
shown in FIG.
26
.
First of all, the video camera
2001
captures image and voice, and outputs analog audio information and analog video information, separately.
The audio capture means
2002
receives the analog audio information output from the video camera
2001
and outputs digital audio information. On the other hand, the video capture means
2005
receives the analog video information output from the video camera
2001
and outputs digital video information.
The video coding means
2006
receives the digital video information output from the video capture means
2005
, compresses the video information by coding, and outputs coded video information corresponding to a single still picture. The coded video storage means
2007
adds a video sequence header to the head of the coded video information. The file management means
2008
stores the coded video information with the sequence header in a file in a storage unit.
The conventional video/audio coding and multiplexing apparatus repeats, three times, the process steps from coding by the video coding means
2006
to storage in the file by the file management means
2008
. Since the coded video information is output every {fraction (1/30)} sec, when the process steps have been repeated three times, the elapsed time is 0.1 sec ({fraction (1/10)}).
The audio coding means
2003
receives the digital audio information output from the audio capture means
2002
, compresses the audio information by coding, and outputs coded audio information by a quantity equivalent to 0.1 sec. The coded audio storage means
2004
a
Matsumoto Takao
Yoneda Aki
Lee Chiho Andrew
Matsushita Electric - Industrial Co., Ltd.
Nguyen Chau
Parkhurst & Wendel L.L.P.
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