What's the difference between MP4 and MPEG4?

Mp4 is a file format, while mpeg4-4 is a coding standard. They are not the same concept. You can understand that mp4 is an audio and video file supporting MPEG-4 standard, and there are many file formats supporting MPEG-4 standard, among which mp4 and avi are one.

MP4 is a set of compression coding standards for audio and video information, which is formulated by the Moving Picture Expert Group (MPEG) under the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). The first edition adopts 1998 10, and the second edition adopts 1999 65438.

The main uses of MPEG-4 format are online streaming media, CD-ROM, voice transmission (video phone) and TV broadcasting.

MPEG-4 contains most of the functions of MPEG- 1 and MPEG-2 and the advantages of other formats, and it also increases and expands the support for interactive functions such as virtual reality modeling language (VRML), object-oriented synthetic files (including sound effects, videos and VRML objects) and digital rights management (DRM).

Compared with MPEG-2, a more advanced feature of MPEG-4 is that macroblocks are no longer used for image analysis, but record a single change in the image. So even if the image changes quickly and the code rate is insufficient, there will be no block diagram.

Extended data

Characteristics of MPEG-4

(1) Different objects can use different coding algorithms, thus further improving the compression efficiency;

(2) The objects are relatively independent, which improves the reusability of multimedia data;

(3) Allow users to operate a single object, providing unprecedented interactivity;

(4) Allow flexible allocation of code rates among different objects, with more bytes allocated to important objects and fewer bytes allocated to secondary objects, thus achieving better results at low code rates;

(5) Natural audio and video objects and synthetic audio and video objects can be easily integrated.

Because MPEG-4 is an open platform, companies and institutions can develop different formats according to MPEG-4 standard, so many video formats based on MPEG-4 technology have appeared in the market, such as WMV 9, Aauto Quicker, DivX, Xvid and so on. Most of the functions of MPEG-4 are left to the developers to decide whether to adopt them or not.

This means that a program may not completely cover the functions of the whole format. So this format has the so-called profile and level, and defines the function set when MPEG-4 is applied to different platforms.

References:

Mp4。 Baidu baike