Methods and apparatus for selecting and switching input video tracks using track derivations

An apparatus comprising a processor in communication with memory, the processor being configured to execute instructions stored in the memory that cause the processor to perform:

• accessing multimedia data comprising:
• a plurality of media tracks, each media track comprising an associated series of samples of media data;
• and
• a derived track comprising a set of derivation operations to perform to generate a series of samples of media data for the derived track;
• and
• performing a derivation operation of the set of derivation operations to generate a portion of media data for the derived track, comprising:
• determining, based on the derivation operation, a group of media tracks from the plurality of media tracks, comprising determining each media track in the group of tracks meets a grouping criteria, wherein the group of media tracks is a subset of the plurality of media tracks;
• selecting one media track from the group of media tracks;
• and
• adding a sample from the one media track to the derived track to generate the portion of the derived track.

An apparatus comprising a processor in communication with memory, the processor being configured to execute instructions stored in the memory that cause the processor to perform:

• encoding multimedia data comprising:
• a plurality of media tracks, each media track comprising an associated series of samples of media data;
• and
• a derived track comprising a set of derivation operations to perform to generate a series of samples of media data for the derived track, wherein a derivation operation of the set of derivation operations provides for generating a portion of media data for the derived track by:
• determining, based on the derivation operation, a group of media tracks from the plurality of media tracks, comprising determining each media track in the group of tracks meets a grouping criteria, wherein the group of media tracks is a subset of the plurality of media tracks;
• selecting one media track from the group of media tracks;
• and
• adding a sample from the one media track to the derived track to generate the portion of the derived track.