Replace the decoder-less AvPlayer with a player that demuxes MP4 sources
with FFmpeg (opened by path or through the title's file replacement),
decodes H.264 and AAC on their own threads, and hands out NV12 frames and
interleaved 16-bit PCM in buffers from the title's allocators, presented
on a media clock that audio drives when it is enabled.
Both libSceAvPlayer and libSceAvPlayer.native are built from the same
sources and link the shared ffmpeg target. The struct size checks stay,
next to the types in SceTypes.hpp. ChangeStream and GetStreamInfoEx are
implemented; Init without allocators, StartEx, SetAvailableBandwidth,
SetLogCallback and negative trick speeds succeed as before and are listed
in TechnicalDebt. HLS sources throw.
guest_avplayer plays an embedded 6 KB MP4 (H.264 plus two AAC tracks).
Dean Galvin