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H.264 MPEG 白皮书
资料介绍
做了个合集关于H264学习的 都是经典资料
部分文件列表
| 文件名 | 大小 |
| H.264_MPEG-4Part10WhitePaper.pdf | 910K |
部分页面预览
（完整内容请下载后查看）www.vcodex.com
H.264 / MPEG-4 Part 10 : Overview
H.264 / MPEG-4 Part 10 White Paper
Overview of H.264
1. Introduction
Broadcast television and home entertainment have been revolutionised by the advent of digital TV and
DVD-video. These applications and many more were made possible by the standardisation of video
compression technology. The next standard in the MPEG series, MPEG4, is enabling a new generation
of internet-based video applications whilst the ITU-T H.263 standard for video compression is now
widely used in videoconferencing systems.
MPEG4 (Visual) and H.263 are standards that are based on video compression (“video coding”)
technology from circa. 1995. The groups responsible for these standards, the Motion Picture Experts
Group and the Video Coding Experts Group (MPEG and VCEG) are in the final stages of developing
a new standard that promises to significantly outperform MPEG4 and H.263, providing better
compression of video images together with a range of features supporting high-quality, low-bitrate
streaming video. The history of the new standard, “Advanced Video Coding” (AVC), goes back at
least 7 years.
After finalising the original H.263 standard for videotelephony in 1995, the ITU-T Video Coding
Experts Group (VCEG) started work on two further development areas: a “short-term” effort to add
extra features to H.263 (resulting in Version 2 of the standard) and a “long-term” effort to develop a
new standard for low bitrate visual communications. The long-term effort led to the draft “H.26L”
standard, offering significantly better video compression efficiency than previous ITU-T standards. In
2001, the ISO Motion Picture Experts Group (MPEG) recognised the potential benefits of H.26L and
the Joint Video Team (JVT) was formed, including experts from MPEG and VCEG. JVT’s main task
is to develop the draft H.26L “model” into a full International Standard. In fact, the outcome will be
two identical) standards: ISO MPEG4 Part 10 of MPEG4 and ITU-T H.264. The “official” title of the
new standard is Advanced Video Coding (AVC); however, it is widely known by its old working title,
H.26L and by its ITU document number, H.264 [1].
2. H.264 CODEC
In common with earlier standards (such as MPEG1, MPEG2 and MPEG4), the H.264 draft standard
does not explicitly define a CODEC (enCOder / DECoder pair). Rather, the standard defines the
syntax of an encoded video bitstream together with the method of decoding this bitstream. In practice,
however, a compliant encoder and decoder are likely to include the functional elements shown in
Figure 2-1 and Figure 2-2. Whilst the functions shown in these Figures are likely to be necessary for
compliance, there is scope for considerable variation in the structure of the CODEC. The basic
functional elements (prediction, transform, quantization, entropy encoding) are little different from
previous standards (MPEG1, MPEG2, MPEG4, H.261, H.263); the important changes in H.264 occur
in the details of each functional element.
The Encoder (Figure 2-1) includes two dataflow paths, a “forward” path (left to right, shown in blue)
and a “reconstruction” path (right to left, shown in magenta). The dataflow path in the Decoder
(Figure 2-2) is shown from right to left to illustrate the similarities between Encoder and Decoder.
© Iain E G Richardson
07/10/02
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