MPEG-4 Part 14

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MP4 is a video container format for MPEG-4 content provided by the MPEG and ISO / IEC 14496-12 and -14 (MPEG- 4 Part 12 and 14) was standardized.

The MP4 file format is based on the Apple QuickTime file format. Both formats organize media data in hierarchical and sequential data units. These units are called " atoms", and their TYPE identifier ( moov, trak, mdia, minf, STBL, etc. ) are identical. You can record a variety of different media types and save with structural information and their dependencies.

Add MP4 files multimedia content in the form of multiple audio and video tracks and subtitles, 2D and 3D graphics can be saved. This content can then play it locally using appropriate software or streaming over a network.

However, it is not usual to include all available formats to MP4 in order to ensure compatibility between different applications, although it would be theoretically possible by " private" markings (flags or atom ). The MPEG has the container therefore limited to the following formats:

The ATSC has also AC-3 specified for the mp4 container, but MPEG support this codec not official.

Alternative container formats are AVI, Matroska and Ogg Media.

File extension

The file extension of mp4 files has already donated some confusion among users. The only specified in the standard file extension is mp4. ; but since mp4 is a container format, it gives no indication of the exact content of the file. That's why Apple is asking for more file extensions that should rename mp4 files clearer. Where:

  • . m4v, mp4v. video: only for video (MPEG- 4 video streams )
  • . m4a: Audio: only for audio (MPEG -4 Part 3, AAC, or for the codec Apple Lossless )
  • . m4b: Audio Book: identifies audio books, can be put into the bookmarks
  • . m4p: Protected: DRM - protected AAC
  • . m4r: Ringtone: Ringtone for iPhone

The extensions .3 gp and .3 g2 be used in mobile phones and belong to the 3GPP standard, the MPEG -4 is very similar, but can also use formats that are not common in. Mp4 ( for example, the AMR voice codecs).

Audioformat Technical standard Digital container format International Electrotechnical Commission MPEG-1 Audio Layer II MPEG-1 Audio Layer I JPEG MPEG-4 Part 11
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