of calling it at the end of a frame with a large negative offset.
This significantly reduces the maximal distance in container packets between
the point where the first byte of the "access unit" was stored and where
we call ff_fetch_timestamp() thus reducing the constraints on our parser.
Also change the parser from next_frame_offset to cur, this is needed
because now the reference is from container packet start instead of
frame start. (i previously misinterpreted this as bug)


git-svn-id: file:///var/local/repositories/ffmpeg/trunk@17731 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b