Motion video signal processing for recording or reproducing – Local trick play processing – With randomly accessible medium
Reexamination Certificate
2001-10-30
2004-01-13
Nguyen, Huy (Department: 2615)
Motion video signal processing for recording or reproducing
Local trick play processing
With randomly accessible medium
C386S349000
Reexamination Certificate
active
06678468
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a video and audio coding method, a coding apparatus, and a coding program recording medium and, more particularly to a coding method, a coding apparatus and a coding program recording medium in which video, audio, or video and audio are captured and coded under software control using a general purpose computer resource.
BACKGROUND OF THE INVENTION
Techniques for digitizing video or audio as analog data to obtain digital video data or audio data have been widespread and developed because it is easy to handle recording, transmission, editing, and reproduction of digital data. An advantage of digitization is that data can be compressed with ease and compressive coding is very important especially for recording or transmission. For the compressive coding techniques, international standards have been established, among which MPEG (Moving Picture Experts Group) standard is well-known as a general digital standard in which video or audio may be handled.
In addition, with high-speed and low-cost semiconductor devices in computers and VLSI or the like, cheap personal computers which are called multimedia personal computers are on the market. As a result, regeneration of video and audio as compressively coded digital data by conventional addition of decode hardware can be easily realized in the personal computers by a software. Also, delivery of video or audio is performed by an internet and coded data of video and audio according to MPEG is extensively utilized.
As concerns coding to produce coded data of video or audio, software processing is difficult in the personal computer and special hardware must be added thereto. Though it is possible to perform coding by software processing after recording video and audio as files, it takes time several times as long as input time of video and audio to perform conversion, so that it is not appealing to the user.
In order to realize that general personal computer users can capture video including a moving picture or audio to produce coded data, it is desired that a capture board or a sound board is used to capture a moving picture or audio and real-time coding can be performed by a software, which must be developed with progress and spread use of hardware.
A prior art apparatus which performs “A video coding”, “B audio coding” and “C video and audio coding” is described hereinafter as an example of a status quo of video, audio or video and audio coding.
A. Prior Art Video Coding Apparatus
Video including a moving picture or a still picture is digitized in real time and captured into a computer to perform coding processing in real time by using an expansion card for personal computer which performs coding the video in real time according to the MPEG as an international standard of moving picture compress ion.
FIG. 58
is a block diagram illustrating a Structure of a video coding apparatus that is realized in a computer including such special hardware. As Shown in Figure, the prior art video coding apparatus comprises a coding section
5001
and a coding parameter decision means
5002
, the apparatus inputting video as input picture data and outputting video coded data. The coding section
5001
includes a DCT (discrete cosine transform) processing means
5003
, a quantization means
5004
, a variable length coding means
5005
, a bit stream generating means
5006
, an inverse quantization means
5007
, an inverse DCT processing means
5008
, and a prediction picture generating means
5009
.
In the Figure, the coding section
5001
is used for inputting video data comprising a series of still pictures in which video is digitized as input picture data and performing coding processing according to set coding parameters to output coded data. Individual still picture data constituting input picture data is referred to as a frame picture. The coding parameters are given by the coding parameter decision means
5002
mentioned later as indicators of a coding type and resolution.
The coding parameter decision means
5002
is used for deciding a coding type indicating an intra-frame coding or an inter-frame coding and resolution, and outputting the same to the coding section
5001
.
In the coding section
5001
, the DCT means
5003
is used for performing DCT processing to the input picture data and outputting resulting DCT data. The quantization means
5004
is used for quantizing the DCT data and outputting quantized data. The variable length coding means
5005
is used for performing variable length coding processing to quantized data to produce variable length coded data that is compressively coded. The variable length coded data is input to the bit stream generating means
5006
, from which coded data of the video coding apparatus is output as a bit stream which can be transmitted and recorded.
The inverse-quantization means
5007
is used for performing inverse-quantization processing to the quantized data that is output from the quantization means
5004
and outputting inverse-quantized data. The inverse-DCT means
5008
is used for performing inverse-DCT processing to inversely-quantized data and outputting resulting inverse DCT data, which is input to the prediction picture generating means
5009
and output as prediction picture data. In case of coding using prediction picture in accordance with the coding parameters, difference data between the prediction picture data and the input picture data is input, thereby inter-frame coding is performed in the coding section
5001
.
An operation of video coding in the video coding apparatus constructed above is described hereinafter.
Prior to coding, the coding parameter decision means
5002
decides coding parameters including a coding type and resolution and outputs the same to the coding section
5001
.
Generally, compressive coding includes an intra-frame coding in which a still picture of a frame (corresponding to a screen) is compressed excluding redundancy based on a spatial correlation (intra-frame correlation) thereof, and an inter-frame coding in which still pictures of consecutive frames that are close in time are compressed excluding redundancy based on time correlation (inter-frame correlation).
The prior art video coding apparatus basically performs intra-frame coding. In addition to the intra-frame coding, the apparatus performs inter-frame coding, thereby coded data with high-compression ratio is obtained. However, to perform inter-frame coding, prediction pictures are produced by decoding or motion detection and motion compensation processing, and difference between the prediction picture and a picture to be coded is obtained. These processing causes increased burden on the apparatus. For generation of the prediction picture in inter-frame coding, forward prediction on the basis of previously processed data, backward prediction on the basis of subsequently processed data, and bidirectional prediction in which the forward prediction or backward prediction is performed, one of which is employed. Hereinafter, the intra-frame coding, the forward predictive coding, the bidirectionally predictive coding (including the backward coding) are represented by “I”, “P”, and “B”, respectively.
Resolution of a picture is generally represented by a number of pixels in longitudinal and lateral directions in a screen such as “320×240” or “160×120”. High resolution, i.e., many pixels in one screen can provide data of high playback quality of picture. However, targets to be processed is increased, causing increased burden on processing.
To conform to the MPEG standard, it is necessary to input/output or transfer data at a given transfer rate. Coded data must be output with this transfer rate satisfied. In case of processing video, the transfer rate is generally expressed as a frame rate that is represented by a number of frames per/sec.
Therefore, it is desirable to set parameters so that real-time processing is performed to captured video with the frame rate satisfied and simultaneously coded data of high playback quality of picture (high
Arase Yoshitaka
Horiuchi Koichi
Kawahara Eiji
Matsumoto Takao
Tatsumi Hidenori
Matsushita Electric - Industrial Co., Ltd.
Nguyen Huy
Parkhurst & Wendel L.L.P.
LandOfFree
Video and audio coding method, coding apparatus, and coding... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Video and audio coding method, coding apparatus, and coding..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Video and audio coding method, coding apparatus, and coding... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3194025