Flattens the representations across all adaptation sets for the given Period
that the MSE media pipeline can play, i.e. audio and video.
Text adaptation sets (e.g. contentType="text" WebVTT sidecar subtitles) are
excluded: they are surfaced through the sidecar text-track pipeline
(discoverDashTextTracks), not buffered through MSE, so including them here
would create an unplayable text SourceBuffer and stall playback.
Flattens the representations across all adaptation sets for the given Period that the MSE media pipeline can play, i.e.
audioandvideo.Text adaptation sets (e.g.
contentType="text"WebVTT sidecar subtitles) are excluded: they are surfaced through the sidecar text-track pipeline (discoverDashTextTracks), not buffered through MSE, so including them here would create an unplayable text SourceBuffer and stall playback.