demux_mkv: return unique file positions for all packets

Until now, some packets could return the same file position if they were
split off from a Matroska-level packet. This was perfectly fine, because
the file position isn't used for anything overly important (it uses it
to estimate playback position if no other information is available). The
following commit will use the demux_packet.pos field as unique ID (as a
simplification), so make the demuxer export more finegrained
information.

Also, the last_filepos field didn't have to be global, at least not
anymore.

0 files changed, 0 insertions, 0 deletions