What format is mpeg-4?

mpeg-4 is a set of compression coding standards for audio and video information. It is a compression format. The first version was adopted in October 1998, and the second version was adopted in December 1999. The main uses of the MPEG-4 format are network streaming, optical discs, voice transmission (video telephony), and television broadcasting.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

MPEG-4 is a set of compression coding standards for audio and video information. It is developed by the "Moving Picture Experts Group" under the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). MPEG) was formulated, the first version was adopted in October 1998, and the second version was adopted in December 1999. The main uses of the MPEG-4 format are network streaming, optical discs, voice transmission (video telephony), and television broadcasting.

MPEG-4 contains most of the functions of MPEG-1 and MPEG-2 and the advantages of other formats, and adds and expands support for Virtual Reality Modeling Language (VRML), for Composite files of objects (including sound effects, video and VRML objects), as well as digital rights management (DRM) and other interactive features. One of the features of MPEG-4 that is more advanced than MPEG-2 is that it no longer uses macro blocks for image analysis, but records changes on individuals in the image. Therefore, even if the image changes quickly and the bit rate is insufficient, it can No block screen will appear.

MPEG-4 is a standard that is composed of several sub-standards (parts) and is still evolving. Various companies' products that are advertised as being compatible with MPEG-4 often do not clearly state which sub-standards they are compatible with. . The most important sub-standards are MPEG-4 Part 2 and MPEG-4 Part 10.

Because MPEG-4 is an open platform, companies and institutions can develop different formats based on the MPEG-4 standard , so there are many video formats based on MPEG-4 technology on the market, such as WMV 9, Quick Time, DivX, Xvid, etc. Most features of MPEG-4 are left to developers to decide whether to adopt them. This means that the functionality of the entire format may not be fully covered by a single program. Therefore, this format has so-called profiles and levels, which define the set of functions of MPEG-4 when applied to different platforms.

Compared with MPEG1 and MPEG2, MPEG4 has higher interactivity and flexibility. The standard of MPEG4 technology is to encode the content in moving images. Its specific encoding object is the audio and video in the image. , the term is called "AV object", and continuous AV objects combined together can form an AV scene. Therefore, the MPEG4 standard is developed around the encoding, storage, transmission and combination of AV objects. Efficiently encoding, organizing, storing and transmitting AV objects is the basic content of the MPEG4 standard.

The advantage of MPEG4 lies in its compression ratio (up to 4000:1). Since MPEG4 abandons the same elements and only processes elements that are different between image frames, it greatly reduces the number of synthesized multimedia files. volume. Coupled with its low bit rate, less core program space, enhanced computing capabilities, and powerful communication application integration capabilities, MPEG4 has become the most important feature and standard format in the audio-visual digital video industry.

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