Introduction of common video formats and video codec standards

"Popular video formats"

To count, video files can be divided into two categories: one is image files, such as the common VCD is an example. The second is streaming video files, which is the development of the Internet with the advent of the emergence of the video show, such as live broadcast online, is framed in streaming video technology. Streaming video (streaming) uses a "side-by-side multicast" approach, which is to download a portion of the video file from the server, form a video stream buffer to play in real-time, and continue downloading for the next play ready. This "side-by-side-broadcast" approach avoids the disadvantage of users having to wait for the entire file to be downloaded from the Internet for viewing.

1.AVI format
Its English is all called the Audio Video interleaved, which is the interleaved format of the audios. It was introduced by Microsoft in 1992 and is known and understood along with Windows3.1. The so-called "audio Video interleaving", is the video and audio can be interleaved together for simultaneous playback. The advantage of this video format is good image quality, can be used across multiple platforms, but the disadvantage is that the volume is too large, and worse, the compression standard is not uniform, so often encounter the high-version Windows Media Player can not play with early encoding editing AVI format video, The low-version Windows Media Player cannot play the AVI format video with the latest encoded edits. In fact, the solution is very simple, we will be in the video conversion, video repair part of the solution.
2.dv-avi format
DV English full name is digital video format, is a combination of Sony, Panasonic, JVC and many other manufacturers to put forward a home digital video formats. A very popular digital camera is the use of this format to record video data. It can transfer video data to the computer via the computer's IEEE 1394 port, or it can record the edited video data from the computer to the digital camera. This video format file extension is generally also. avi, so we used to call it for the Dv-avi format.
3.MPEG format
Its English is all called Moving Picture Expert Group, which is the format of the motion image expert groups, the VCD, SVCD and DVD which are often seen in the home. MPEG file format is an international standard of motion image compression algorithm, which uses lossy compression method to reduce redundant information in moving image. MPEG compression method said more in depth is to retain the next two images of the vast majority of the same part, and the subsequent image and the previous image has redundant parts removed, thereby achieving the purpose of compression. The current MPEG format has three compression standards, namely MPEG-1, MPEG-2, and MPEG-4, in addition, MPEG-7 and MPEG-21 are still in the research and development stage.
MPEG-1: Established in 1992, it is an international standard designed for digital storage media motion images and their sound coding for data transfer rates below 1.5Mbps. That's what we usually see in VCD production format. The file extensions for this video format include. mpg,. MLV,. MPE,. mpeg, and. dat files in the VCD CD.
MPEG-2: Developed in 1994, the design target is high industry standard image quality and higher transmission rate. This format is mainly used in the production of DVD/SVCD (compression), but also in some HDTV (high-definition TV broadcast) and some high-demand video editing, processing, there is a considerable application. The file extensions for this video format include. mpg,. MPE,. mpeg,. M2V, and. vob files on DVD discs.
MPEG-4: Developed in 1998, MPEG-4 is specifically designed to broadcast high-quality video streaming media, which uses a narrow band to compress and transmit data with frame reconstruction techniques to achieve the best image quality with minimal data. The most attractive part of MPEG-4 is its ability to save small video files that are close to the quality of the DVD. The file extensions for this video format include. asf,. mov and DivX, AVI, and so on.
4.DivX format
This is another video coding (compression) standard derived by MPEG-4, also known as the DVDRip format, which uses the MPEG4 compression algorithm and combines MPEG-4 and MP3 technologies, It is plain to use DivX compression technology to compress the video image of the DVD disc, while compressing the audio with MP3 or AC3, and then synthesizing the video and audio together with the corresponding external caption file to form the video format. Its picture quality is almost as large as DVD and only a fraction of the size of DVDs.
5.MOV format
A video format developed by the American Apple Company, the default player is Apple's quicktimeplayer. Features high compression ratios and perfect video clarity, but its biggest feature is cross-platform, which not only supports MacOS, but also supports the Windows family.
Its English is all called Advanced Streaming format, a video format that Microsoft has launched to compete with today's real player, and users can play it directly with Windows Media Player, which Windows comes with. Because it uses the MPEG-4 compression algorithm, the compression rate and image quality are very good. ) l& _& f$ a# F4 _! R

7.WMV format
Its English is all called Windows Media Video and is a file compression format that Microsoft has introduced in an independent way and that can watch video programs live directly on the web. The main benefits of WMV format include: local or network playback, expandable media types, scalable media types, multi-lingual support, environmental independence, rich inter-flow relationships, and extensibility.
8.RM format
The audio and video compression specifications developed by networks are called real Media, and users can use RealPlayer or RealOne player for live broadcast of network audio/video resources that conform to RealMedia specifications, And RealMedia can also make different compression ratios according to different network transmission rates, so as to realize real-time transmission and playback of image data on low-rate network. Another feature of this format is that users can play online without downloading audio/video content using the RealPlayer or RealOne player player.
9.RMVB format
This is a new video format by the RM video format upgrade, it is advanced in that RMVB video format to break the original RM format of the average compression sampling method, on the basis of guaranteed average compression ratio, reasonable use of bit rate resources, that is, static and action scenes less scenes with low encoding rate, This allows for more bandwidth space, which can be exploited in the event of a fast moving picture scene. In this way, in order to guarantee the quality of the still picture, the picture quality of the moving image is greatly improved, thus the image quality and the file size can be balanced in a delicate manner.

10.ASF (Advanced Streaming format) formats
Microsoft Company's ambitious streaming format (ASF, Advanced Streaming format), which is also a technical standard for real-time multimedia dissemination on the Internet, Use ASF instead of technical standards such as QuickTime. The main benefits of ASF include: local or network playback, expandable media types, component downloads, and extensibility. The main components of the ASF application are the NetShow server and the NetShow Player. There is a separate encoder that compiles the media information into an ASF stream, which is then sent to the NetShow server, which is then sent by the NetShow server to all NetShow players on the network for single or multicast broadcasts. This is similar to real-time retransmission.


Common video coding and decoding standards

Many video codecs can be easily implemented on personal computers and consumer electronics, which makes it possible to implement a variety of video codecs at the same time, which avoids the fact that some dominant codec affects the development and promotion of other codecs due to compatibility. Finally, we can say that there is no such codec that can replace all other codecs. Here are some popular video codecs that are sorted by the time they become international standards:

H.261
H.261 is mainly used in old video conferencing and video telephony products. H.261 was developed by ITU-T, the first to use the digital video compression standard. Essentially, all of the standard video codecs that followed were based on it. It uses a common ycbcr color space, 4:2:0 chroma sampling format, 8-bit sampling accuracy, 16x16 macro block, block motion compensation, discrete cosine transform by 8x8 block, quantization, zig-zag scanning of quantization coefficients, run-level symbolic innuendo, and Hoffmann coding. H.261 only supports progressive scan of video input.
MPEG-1 Part II
MPEG-1 the second part is mainly used on VCD, some online videos also use this format. The quality of the codec is roughly the same as the original VHS tape, but it is worth noting that VCD belongs to digital video technology, it will not be like VHS tape as the number of times and time and gradually lost quality. If the input video source quality is good enough, the code rate is high enough, VCD can be given in all respects than VHS to high quality. But in order to achieve this goal, the VCD usually needs a higher bitrate than the VHS standard. In fact, if you consider that all VCD players can play, more than 1150kbps video bitrate or higher than 352x288 video resolution can not be used. Generally speaking, this restriction is usually only valid for some single VCD players (including some DVD players). MPEG-1 The third part also includes the current common *.mp3 audio codec. For versatility, MPEG-1 's video/audio codec is the most versatile codec, and almost all computers in the world can play files in MPEG-1 format. Almost all DVD players also support VCD playback. Technically speaking, MPEG-1 increases the half-pixel motion compensation and bidirectional motion prediction frames compared to the h.261 standard. Like H.261, MPEG-1 only supports progressive scan of video input.
MPEG-2 Part II
The second part of MPEG-2 is equivalent to h.262, which is used in DVDs, SVCD and most digital video broadcasting systems and wired distribution systems (cable distribution system). When used on a standard DVD, it supports high image quality and widescreen, and when used in SVCD, its quality is not as good as DVD but much higher than VCD. Unfortunately, SVCD can hold up to 40 minutes of content on a CD, while a VCD can hold one hours, meaning SVCD has a higher average bitrate than a VCD. MPEG-2 will also be used on the next-generation DVD standard Hd-dvd and Blu-ray (Blu-ray discs). Technically speaking, the biggest improvement over mpeg-1,mpeg-2 is the increased support for interlaced video. MPEG-2 can be said to be a fairly old video coding standard, but it has a lot of popularity and market acceptance.
H.263
H.263 is mainly used in video conferencing, video telephony and network video. In the aspect of compressing the video source with progressive scan, H.263 has a higher performance than the previous video encoding standard. Especially in the low-bit rate, it can be guaranteed a certain quality under the premise of greatly saving the code rate.
MPEG-4 Part II
MPEG-4 the second part of the standard can be used on network transport, broadcast, and media storage. Compared to the MPEG-2 and the first version of the H.263, it has improved compression performance. The main difference from the previous video coding standard is that the "Object-directed" (object-oriented) encoding method and some other techniques that are not used to improve the compression rate of the usual video encoding. Of course, it also introduces some techniques for improving compression capabilities, including some h.263 techniques and 1/4-megapixel motion compensation. Like MPEG-2, it supports progressive and interlaced scanning.
Part tenth (H. MPEG-4): The best Performance Video coding standard
The tenth part of the MPEG-4 is technically the same standard as ITU-T H-I, sometimes called "AVC". This newly-developed standard is the best-performing video coding standard for ITU-T VCEG and ISO/IEC MPEG, and has been increasingly used. The standard introduces a series of new technologies that can greatly improve the compression performance, and can significantly exceed the previous standards at both the high bit rate and the low bit rate end. Products that have been used and are about to use the H + technology include the Nero Digital product suite for Sony's Psp,nero company, Apple's Mac OS X v10.4, and the next-generation DVD standard HD-DVD and Blu-ray Disc (Blu-ray).
Avs
AVS is a Chinese set of audio and video compression coding standards, so accurately, it not only includes video coding standards. Its main purpose is to avoid paying a large patent licensing fee by adopting a different patent licensing method with H. Technically, the video coding of AVS is very similar to that of H. A, but some simplification measures are adopted. In doing so, one can avoid some non-essential patents, and it is also said that it can improve the codec speed on the basis of almost no effect on coding compression efficiency.
Divx,xvid and 3ivx
Divx,xvid and 3ivx video codecs basically use the technology of the second part of MPEG-4, and the later suffix *.avi, *.mp4, *.OGM, or *.mkv end files are part of the use of these video codecs.
Wmv
WMV (Windows Media Video) is a family of Microsoft's video codecs, including WMV 7, WMV 8, WMV 9, and WPV 10. This family of codecs can be applied to broadband video from dial-up internet-based narrowband video to high-definition television (HDTV). Using Windows Media Video users can also burn video files to CDs, DVDs, or other devices. It is also suitable for use as a media server. WMV can be seen as an enhanced version of MPEG-4. The latest version of WMV is the VC-1 standard that is being developed in SMPTE. WMV-9 (VC-1, the development code for "Corona") just launched the time called VC-9, then was the film and Television Engineers Association (SMPTE) called VC-1 (VC refers to video Codec). Technically, VC-1 also has a lot in common with H.
RealVideo
RealVideo is a video codec developed by RealNetworks Corporation. In recent years there has been a period of downturn, and then won the favor of the market. Recently, especially in the BT film industry particularly favored.
Sorenson 3
Sorenson 3 is a codec used by Apple's software QuickTime. Many QuickTime video formats on the Internet are compressed by this codec.
Cinepak
Cinepak is also a very old codec used by Apple's software QuickTime, and the advantage is that even very old computers (such as 486) are supported and able to play smoothly.
Indeo Video
Indeo Video Indeo Video is a codec developed by Intel.
The codec mentioned above has its own advantages and disadvantages, often can see the comparison of these codecs, this time the most important consideration is the code rate and clarity (often said the law distortion characteristics, robustness).