Overview: Timing and navigation

Container timing and navigation connect packet clocks, playback positions, seek indexes and chapter locations.

A position in a media file is not automatically a position on the playback clock. Timestamps and time bases describe when data belong; indexes describe how to find a useful place to resume decoding, and chapters attach named navigation points. Together these topics explain how a player reaches the requested moment rather than merely opening a byte offset.

• Packet timestamps
  Packet timestamps tell a playback pipeline when encoded media must be decoded and when the resulting content should be presented.

• Time bases
  A time base defines the duration of one timestamp tick so integer media timestamps can be converted to real time.

• Container indexes and seeking
  A container index connects points on the media timeline to file locations so a player can seek efficiently.

• Chapter markers
  Chapter markers give named navigation points within a media presentation without splitting it into separate files.