This commit splits out synchronization primitives from LibThreading into
LibSync. This is because LibThreading depends on LibCore, while LibCore
needs the synchronization primitives from LibThreading. This worked
while they were header only, but when I tried to add an implementation
file it ran into the circular dependency. To abstract away the pthread
implementation using cpp files is necessary so the synchronization
primitives were moved to a separate library.
The segments are parsed for the SourceBufferProcessor by the
WebMByteStreamParser. It parses the initialization segment to update
its internal set of tracks, then SourceBufferProcessor/SourceBuffer set
them up for playback. When a media segment is received, it also parses
as much of it as is available, returning all the coded frames found so
far. SourceBufferProcessor then tells TrackBufferDemuxer to remove any
overlapping frames and insert the new ones.
TrackBufferDemuxer implements the Demuxer interface in terms of the
coded frame store maintained by the SourceBufferProcessor. It returns
the frames in decode order when requested by a data provider. When a
is needed, it finds the keyframe prior to the target timestamp, and
checks that there are no gaps in data up to the target timestamp. If
there are any gaps, it blocks until the gaps are gone.
