Difference between MPEG-4, MPEG-4 / AVC, H.264
When you download a video on the Internet, often you see MPEG-4, h.264 etc words, what is the relationship between them?
There are two standards in terms of video codec technology definition. One is the International Telecommunications Union (ITU), which is committed to telecom application, has developed H.26X standard for low bit rate video phones, including H.261, H.262, H.263 and H.264; another It is an International Standardization Organization (ISO), mainly for consumer applications, have defined MPEG standards for moving image compression. The MPEG standards include MPEG-1, MPEG-2 and MPEG-4.
I. When MPEG-4 is developed, the positioning standards are high-level media representations and structures, but with the rapid development of computer software and network technology, MPEG-1 and MPEG-2 drawbacks displayed: low interactivity and flexibility, compressed multimedia file size too large, it is difficult to achieve real-time communication networks. The standard for MPEG-4 (MPEG-4 Part 2) is to encode content in motion images. The specific encoding object is audio and video in the image, and the term is called "AV object", highly efficiently encoded. Organizational, storage, and transmission AV objects are the basic content of the MPEG-4 standard. In video encoding, MPEG-4 supports encoding of natural and synthetic visual object (including the synthetic visual objects 2D, 3D animation, and human facial animation, etc.). On the audio coding, MPEG-4 can be audio encoding with natural sound objects such as voice, music, etc., with a natural sound object such as voice, music, and synthetic sound objects with echo, spatial orientation. Be
Second, about H.264 to develop international telecommunications Alliance Telecommunications Standards Branch ITU-T, completing H.263 (streaming video standard for video conferencing), working with ISO / IEC institutions The two institutions jointly set up a joint working group called JVT (Joint Video Team), which is more derivatives used by the MPEG-4 technology for video conferencing (Video Conference), jointly developed a new standard. This standard, the ITU-T is called H.264. However, ISO / IEC will focus on this new standard in the MPEG series called MPEG-4 Part 10 (Part 10, also called ISO / IEC 14496-10), another representation of MPEG-4 Part 10 is MPEG-4 AVC (Advanced Video Coding, Advanced Video Coding). Therefore, the so-called H.264 is actually the same with MPEG-4 / AVC, that is, H.264 = MPEG-4 Part 10 = ISO / IEC 14496-10 = MPEG-4 AVC.
Third, the difference between H.264 and MPEG-4 Since there is MPEG-4 (MPEG-4 Part 2), why is ISO / IEC to develop H.264 with ITU-T? What is the difference between H.264 and MPEG-4? Or what is the difference between MPEG-4 Part 10 with MPEG-4 PART 2? Although MPEG-4 has been designed for Internet transmission, providing more flexible and flexible playback sampling ratio than MPEG-2, but also wants to have further compression on video conferencing, so it is necessary H.264 appeared. Do you know where H.264 is it? We can resolve MPEG-2, MPEG-4 (MPEG-4 Part 2), H.264 (MPEG-4 AVC, MPEG-4 Part 10), and comparison with the bandwidth used, regardless of MPEG-2, MPEG-4, H.264, three of the high definition, HDs, 24fps (updated 24 screens per second), but transmit bandwidth MPEG -2 requires 12 to 20 Mbps, relative H.264 as long as 7 ~ 8Mbps, and MPEG-4 is between two, more directly, if MPEG-2 is used as 100%, MPEG-4 to achieve the same effect required bandwidth of only 60%, H.264 is as low as 40%, about 1/2 to 1/3 of the original MPEG-2. It is worth mentioning that there are two entropy decodes adopted by the H.264 standard: one is based on content-based adaptive beam coding (CAVLC) combined with unified beam coding (UVLC); the other is based on content Adapt to binary arithmetic coding (CABAC). CAVLC is encoded by the CABAC based on the case of the phase block to achieve better coding efficiency. CABAC is higher than CAVLC compression efficiency, and can save about 20% of bandwidth in considerable picture quality, but it is more complicated.
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