Here is only a brief introduction to the common video and audio coding system, and does not discuss it in detail. Due to my limited knowledge, it is inevitable that there are mistakes. Welcome to write me to correct me.
1. MPEG series
MPEG stands for (Moving Pictures Experts Group), which belongs to ISO (International Organization for Standardization). They have developed a series of video and audio coding, the most familiar is MP3, MPEG-1/2/4.
(1) MPEG-1
Earlier video encodings were of poor quality and were mainly used for CD-ROM storage of video. The most familiar one in China is VCD (Video CD), and its video encoding uses MPEG-1.
(2) MPEG-2
A video encoding developed on the basis of MPEG-1. Its quality is far better than that of MPEG-1, so it is used on DVD-Video. MPEG-2 is the only specified video encoding for DVD-Video. MPEG-2 is not only used in DVD-Video, but now most HDTV (high-definition televisions) also use MPEG-2 encoding, with a resolution of 1920x1080. Due to the popularity of MPEG-2, MPEG-3, which was originally prepared for HDTV, was finally abandoned.
(3) MPEG-4
In order to cope with the environment such as network transmission, the traditional MPEG-1/2 can no longer adapt, so the birth of MPEG-4 was promoted. MPEG-4 uses a series of new technologies to meet the demand for high video quality transmission under low bandwidth. DivX, XviD, and MS MPEG4 all use MPEG-4 video coding. In addition to the application on DVDRip, 3GPP now also accepts MPEG-4 as the video coding scheme.
(3) MPEG-4 AVC
It and MPEG-4 are two different encodings, mainly because MPEG-4 does not perform well at very low bit rates, and AVC is more suitable for low-bandwidth transmission. At high bit rates, AVC also performs better than MPEG-4, so there is a trend to replace MPEG-4 now. The next generation of HD DVD and Blue Ray Disc have officially adopted AVC as one of the video coding schemes. I believe that the future of AVC will be very good.
(4) MPEG Audio Layer 1/2
That is, MP1, MP2, the earlier audio coding, is the predecessor of MP3, mainly used for VCD, DVD, SVCD audio coding.
(5) MPEG Audio Layer 3
The famous MP3 has become the mainstream format of network audio, which can approach CD sound quality at a bit rate of 128kbps.
(6) MPEG-2 AAC
A new audio codec developed on MPEG-2 is not compatible with traditional MPEG Audio. Its quality is theoretically higher than MP3 and supports multi-channel. The sound quality of CD can be approached within the code rate range of 96kbps, which is more suitable for bit rate transmission than MP3.
(7) MPEG-4 AAC
AAC has been used as the MPEG-4 standard audio codec. Of course, MPEG-4 Audio has many other audio codecs.
(8) MPEG-4 aacPlus
AAC using SBR band replication technology, SBR technology can reduce the bit rate of audio coding by half without much change in sound quality, and has become a part of the MPEG-4 standard.
(9) MPEG-4 VQF
An audio format developed by NTT has disappeared for a while, and has only been seen in Nero. Now that it has joined the SBR technology and entered the MPEG-4 standard, it seems that it is not reconciled to be forgotten. It is said that it performs better than aacPlus at low bit rates.
(10) mp3PRO
MP3 is a product born with SBR technology, but it has not been promoted much, and it has not entered the standard.
(11) MP3 Surround
Let MP3 plug in multi-channel wings, another MP3 upgrade product developed by Fraunhofer, I heard that DivX 6 is going to use it as an audio codec. Fraunhofer has been focusing on MP3 upgrades, mp3PRO, MP3 Surround, these products are compatible with traditional MP3, but with the endless new encoding, I don’t know how far MP3 can go.
2. DVD series
Speaking of MPEG, one cannot fail to mention the biggest beneficiary of MPEG-2-DVD. Of course, this refers to DVD-Video and DVD-Audio, and some HD DVDs are also involved. DVD encodings are all application-level, they do not develop encodings themselves, which should be distinguished from MPEG.
(1) Dolby Digital AC3
DVD is the de facto audio coding standard, and all DVDs now use it to compress audio, provide a maximum 5.1-channel output support, and can store high-quality audio in a limited space.
(2) Dolby Digital Plus
The audio encoding of the next generation of HD DVD is an upgraded version of AC3, supporting 7.1 or more channels, and the code rate range has also been greatly improved.
(3) MLP Lossless
The lossless audio coding on HD DVD was also developed by Dolby, with a maximum sampling rate of 192KHz, which is also the audio coding standard of DVD-Audio.
(4) DTS
DTS was originally an audio system developed for movie theaters, and was later used in DVDs. It is a strong competitor of AC3, but only D9 can be seen in the DVD. Although the majority of enthusiasts are advocating that its effect is better than AC3, the test is not as good as expected, especially in high frequency. Not as good as AC3.
(5) DTS-HD
The audio coding of the next generation of HD DVD, it and Dolby Digital Plus are both designated as mandatory coding, and it seems that it will be evenly matched with Dolby in the future.
(6) LPCM
Uncompressed PCM encoding can only store two channels, but the sampling rate can be as high as 96KHz, which is the best sound quality in DVD-Video, and of course the volume is the largest.
(7) MPEG Audio
Mainly MP2, which is applied to DVD of PAL format with high compression rate and supports multi-channel (MPEG-2 specification supports multi-channel).
(8) DSD
This seems to be a long way off, but as the biggest competitor of DVD-Audio SACD, let me introduce it by the way. DSD (Direct Stream Digital) direct bit stream digital, introduced by Sony, can avoid the disadvantages of traditional PCM encoding and achieve very high quality. The highest sampling is the same as DVD-Audio, 192KHz.
3. H.26X series
The coding series led by "ITU (International Telecommunication Union)" is mainly used in the real-time video communication field, such as conference TV. As the MPEG series has also begun to enter this field, the two organizations have also begun close cooperation. For example, the recently popular AVC/H.264 is the "VCEG (Video Coding Experts Group) Video Coding Experts Group) under the ITU. It was jointly produced and released by "MPEG (Moving Pictures Experts Group)" under the "ISO (International Organization for Standardization) International Standardization Organization".
(1) H.261
H.261 was formulated by ITU-T for the development of two-way audiovisual services (video telephony, video conferencing) on the Integrated Services Digital Network (ISDN). It was the earliest moving image compression standard and it formulated the video coding in detail. Each part includes motion-compensated inter-frame prediction, DCT transformation, quantization, entropy coding, and rate control adapted to a fixed-rate channel.
(2) H.263
H.263 is a video coding standard formulated by ITU-T for narrowband communication channels lower than 64kb/s. It is developed on the basis of H.261.
(3) H.263+
The second version of H.263 has added many new technologies to expand the application range of H.263.
(4) H.263++
Several options have been added to H.263+ to enhance the error-resistance performance of the bit stream on harsh channels, and at the same time improve the enhanced coding efficiency.
(5) H.264
It is the aforementioned MPEG-4 AVC. H.264 is a new generation video compression coding standard formulated by the Joint Video Group (JVT) composed of ISO/IEC and ITU-T. This standard is named AVC (Advanced Video Coding) in ISO/IEC, as the 10th option of the MPEG-4 standard; it is officially named the H.264 standard in ITU-T.
(6) 3GPP
Now one of the hottest topics in the communications field, since we talked about MPEG and ITU, and these two intricate 3GPP applications, we have to mention it. 3GPP’s video uses MPEG-4 and H.263 encoding, and may also add H.264. Audio uses AAC for music compression, and uses advanced AMR for voice. Another aacPlus is introduced with the V2 version. The effect under the rate is more prominent, and it is also expected to be added to the standard.
4. Windows Media Series
The audio and video coding series led by Microsoft, which appeared mainly for network video transmission, has now marched into HDTV and developed the WMV HD application.
(1) Microsoft MPEG-4 v1/v2/v3
The earliest video encoding used by ASF was developed based on MPEG-4 technology. DivX3.11 was cracked based on Microsoft MPEG-4 v3 and was rewritten later.
(2) Windows Media Video 7
The first Windows Media Video officially developed by Microsoft began to break away from MPEG-4 and was incompatible with MPEG-4. From this point, we can see Microsoft's ambitions. It's a pity that the compression effect of this version is very bad, breaking Microsoft's soaring dream, but it is very fast in compression. Now there are many WMV compressed in this format on the Internet.
(3) Windows Media Video 8
The improved version on the basis of WMV7 does not improve much in terms of quality.
(4) Windows Media Video 9
The highlight of Microsoft is not only this encoding, but the V9 series is a platform that allows Microsoft to challenge MPEG, ITU and other standardization organizations. Although this version is not as strong as Microsoft's, especially at low bitrates, it is worse, but compared with the previous version, it is still very much improved. In particular, the application of WMV HD has allowed Microsoft to enter the video standard field
(5) Windows Media Video 9 Professional
The encoding of WMV HD application is compatible with WMV9, optimized for high bit rate, and the picture is very good. (But can the bit rate of dozens of megabytes be excellent? It's all because of the volume.
(6) Windows Media Video 9 Advanced Profile
With the encoder introduced by Windows Media Player 10, the quality of WMV9 can be further controlled. But it cannot be played on the old version of WMP9, that is, it is not compatible with the old version of WMP9. I really don’t know what Microsoft is doing?
(7) Windows Media Video 9 Screen
Lossless compression coding for static screens, the quality is very good, the compression rate is high, only for non-changes such as the screen.
(8) Windows Media Video 9 Image
Still image compression coding.
(9) Windows Media Audio v1/v2
Microsoft's earliest audio coding technology, used in ASF, was later cracked and used in DivX Audio, and the quality was relatively poor.
(10) Windows Media Audio 7/8/9
With the corresponding audio coding introduced by various WMVs, the quality has been improved steadily, but it has not yet reached the deification of 64kbps CD sound quality.
(11) Windows Media Audio 9 Professional
The new codes appearing in WMA9 are mainly used for multi-channel coding and high sampling rate audio coding, and the quality is good.
(12) Windows Media Audio 9 Voice
For speech coding, the maximum is 20kbps, but compared with AMR, the effect is too bad.
(13) Windows Media Audio 9 Lossless
Lossless audio encoding can perfectly preserve the original quality of the CD. It is a good choice for CD backup, but at the cost of being too large.
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