MPEG-4 Inside – File Format

MPEG-4 Inside – File Format

The MPEG File Format has been designed to satisfy a set of requirements, some of which are listed below

  • Binary assets
  • Hierarchical structure
  • Backward- & forward-compatible
  • Suitable to hold timed content
  • Suitable to exchange content
  • Self-contained (only contain data to be exchanged or all of them)
  • Content can extend on more than one file
  • Suitable for editing
  • Suitable for streaming
  • Can playback local file
  • Can download and play the file
  • Object oriented
  • Separated content and metadata

The figure below depicts the MP File hierarchy in a specific instance


the meaning of some the boxes are

  • ftyp (File Type): File type, version 
  • mdat (Media Data):  Holds media data  (several, non contiguous  possible)
  • moov (Movie):  Holds metadata of a presentation 
  • mvhd (Movie Header):  General info about the movie 
  • trak (Track):  Holds metadata related to one stream 
  • hdlr (Handler):  Stream type
  • dinf/dref (Data Information/Data Reference): Data location (this or remote file) 
  • stbl (Sample Table):  Holds metadata related to samples, sample by sample
  • stsd (Sample Description): decoder configuration for the elementary stream
  • stts (Sample To Time):  DTS for each sample 
  • stsz (Sample To Size):  Size of each sample