DirectSound: use a new strategy for erasing the ring buffer

Close #9275 #9328

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>
demux: ogg: handle opus seeking (fix #9334)
mux: avi: improve RIFF header builder.

Current RIFF header builder was working with static sizes and
was unable to handle extra metadata.

This will also save more than 9.5KB on most files.
mux: avi: add metadata.

Implements INFO LIST chunk.
See OpenDML spec.
mux: avi: use reallocable block instead of fixed size buffer