The IMF Composition Playlist defines Edit Rate values for the Composition itself (/CompositionPlaylist/EditRate) as well as for individual Resources (//Resource/EditRate).
These values define the granularity of time-related parameters specified in the Composition Playlist, including:
- the duration of the Composition itself since the duration of individual segments is a multiple of
/CompositionPlaylist/EditRate; and - the
EntryPointandSourceDurationparameters used to specify the Playable Region of a Resource.
These values do not however specify the sampling rate or playback speed of the essence, which is set by metadata in the underlying Track File, e.g. the Sample Rate item of the File Descriptor for MXF Track Files.