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This article mainly introduces "Android development audio and video protocol analysis". In the daily operation, I believe that many people have doubts about the audio and video protocol analysis of Android development. The editor consulted all kinds of materials and sorted out simple and easy-to-use operation methods. I hope it will be helpful to answer the doubts of "Android development audio and video protocol analysis". Next, please follow the editor to study!

What is a video file?

It generally refers to a file that encapsulates audio and video data in a certain format.

Common audio formats: mp3, wma, avi, rm, rmvb, flv, mpg, mov, mkv, etc.

Common video formats: rmvb, rm, wmv, avi, 3GP, MP4

What is the purpose of the encapsulation format?

In general, there is not only video but also audio in the video file. The function of the encapsulation format is to package the video and audio.

What is 264?

Definition: every frame of video captured by the camera needs to be encoded, due to the spatial and temporal redundancy in the video, which needs to be removed by an algorithm. H264 is an algorithm that specializes in removing these redundancies, which we call H264 coding.

H264 is a new generation coding standard, which is famous for its high compression, high quality and support for streaming media transmission over multiple networks.

Applications: like most videos seen, such as teacher Cang's movies, such as rmvb avi mp4 flv, most of them are encoded by h364

Of course, there will also be different codes like mpeg4 vp9, which are relatively unpopular.

Whether h364 mpeg4 vp9 is based on macroblock coding, the principle is the same, but the algorithm is implemented.

It's just inconsistency.

What's the use of knowing about audio and video protocols?

Understanding the protocol of audio and video is of great help to the subsequent audio and video development. For example, the encoding and decoding of audio and video is based on the protocol.

ITU-T of the two major telecom unions

The Chinese name of ITU-T is the Telecommunication Standards Branch of the International Telecommunication Union (ITU-T for ITU Telecommunication Standardization Sector). It is a branch that specializes in the formulation of telecommunications standards under the management of the International Telecommunication Union.

The agency was founded in 1993 and was formerly known as the International Telegraph and telephone Advisory Committee (CCITT is the French abbreviation for Comit é Consultatif International T é l é phonique et T é l é graphique, International Telegraph and Telephone Consultative Committee) and is headquartered in Geneva, Switzerland.

ISO

ISO (InternationalOrganization for Standardization) International Organization for Standardization was founded in London, England, in October 1946.

International Telecommunication Union (ITU-T) and International Organization for Standardization (ISO) related agreements

ITU and ISO are two different organizations, both have their own different audio and video protocols, but in order to unify, the protocols are standardized and unified from H264.

That is, H264 is also known as MPEG-4 AVC,H265 or HEVC, adding the names of both institutions.

The relationship between ITU and ISO is somewhat similar to China Mobile (ITU) and China Telecom (ISO).

China Mobile, a new communication operator, has rapid development and high activity, and young people use it more often, so more people know H264/H265, and the name is easy to remember.

China Telecom, an established telecom operator, has more influence and develops earlier, so what MPEG AVC and HEVC know is slowly decreasing.

The Development of ITU-T Video coding

H.26X series (led by ITU [International Federation of telex and Video])

H.261: mainly used in old video conferencing and video telephony products

H.263: mainly used in video conferencing, video telephony and network video

Part X of H.264:H.264/MPEG-4 is a video compression standard, a widely used format for recording, compressing and distributing high-precision video.

H.265: efficient video coding is a video compression standard, the successor of H.264/MPEG-4. It can support 4K resolution or even ultra-high definition TV, and the highest resolution can reach 8192 × 4320 (8K resolution). This is the current development trend, and there is no popular coding software.

Other audio and video protocols Google (VP8/VP9)

Developed by Google and currently only used for youtube video playback

Microsoft (VC-1)

Microsoft self-developed Audio and Video Protocol

Domestic independent standard: AVS/AVS+/AVS2

China's audio and video agreement is currently used for CCTV video.

Of course, there are other minority or eliminated audio and video protocols, which are not introduced here.

At present, the mainstream audio and video protocol on the market is H 264, while UHD video uses H 265.

H264 and H265 can be used on all platforms, such as computers, televisions, mobile phones, etc.

Google's vp8/vp9 is currently only used in Google Youtube videos.

The domestic AVS protocol standard is currently used in CCTV video.

At this point, the study of "Android Development Audio and Video Protocol Analysis" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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