ISO Base Media File Format

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File Format
Name ISO Base Media File Format
LoCFDD fdd000079

ISO Base Media File Format (sometimes abbreviated BMFF or ISO BMFF) is a metaformat for "time-based" media formats (mainly audio and video). It is based on the more-general metaformat we're calling boxes/atoms format.

It is defined by Part 12 of the MPEG-4 standard, and also by Part 12 of the JPEG 2000 standard.

Files (almost) always have an "ftyp" box, containing a list of "brands" that give information about the specific file format. See the boxes/atoms article for more about brands.

Much of the format was copied from QuickTime format.

Among the formats based on it are MP4 and MJ2.



There appears to be no simple way to distinguish BMFF from other formats.

A file in boxes/atoms format that has both an "ftyp" box and an "moov" box probably uses a BMFF-based format. However, for compatibility with certain older files, the "ftyp" box can sometimes be omitted if the brand would be "mp41".

A BMFF file may (or may not) be labeled with one or more of the generic BMFF brands: "isom", and "iso[2-9]".

Note that some formats use an "ftyp" box, without being conformant with BMFF (though they may borrow elements from it). An example is JP2.



For media players, etc., refer to the article for the relevant application format.


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