The seconds of audio a piece of the stream carries, as Fmp4VideoSeconds counts video: its samples' durations
on the init's audio track. An avatar's audio track is its voice, so this is how long the piece speaks. null when
the init declares no audio track with a timescale, or the piece cannot be read.
The seconds of audio a piece of the stream carries, as Fmp4VideoSeconds counts video: its samples' durations on the init's audio track. An avatar's audio track is its voice, so this is how long the piece speaks.
nullwhen the init declares no audio track with a timescale, or the piece cannot be read.