ReadonlyBackSeconds of played media a buffering decoder keeps behind the playhead (VideoPlayoutOptions.BackBufferSeconds).
ReadonlyCarriesWhether the element plays the media's own audio (an avatar MP4's voice). The player keeps it current.
Optional ReadonlyClockThe voice's playback clock (VideoPlayoutOptions.Clock), when the player has one: a decoder that paces its own
frames shows each when the clock reaches its PresentationTimeMs. A decoder whose media carries the voice ignores it.
ReadonlyMimeThe player's configured type (VideoPlayoutOptions.MimeType), with its codecs: what a decoder that opens by type
(MSE) opens with until a frame says more.
The decoder can't go on (its browser decoder closed for good, or the browser can't decode the stream's codec). The player disposes it and picks the next decoder that can play the frame's type; out of decoders, frames of that type are dropped.
OptionalOnThe element hook from VideoPlayoutOptions.OnElementAttached: the voice's route into Web Audio. A decoder whose media
carries audio calls it with each element it takes over, before playback starts.
Reports a problem. The player passes each kind on once.
What a decoder plays with and reports through. The player gives one to each decoder it creates.