[Mplayer-dvb] ac3 sound in vdr file not recognized by mplayer and mencoder ?Wed Jan 2 21:17:00 2002

[mocm at convergence.de]

Arpi writes:
 > Hi,
 > 
 > >  > Has anybody tried to watch vdr files with ac3 sound ?
 > > 
 > > My guess would be that the audio PES in the vdr files don't have an
 > > AC3 header. The A52 (AC3 via ATSC and as it seems also DVB) format doesn't 
 > > require the header and if vdr doesn't add the header, mplayer probably
 > > won't recognize it as AC3.
 > 
 > hmm. you're right.
 > my hotfix fixed demuxer, but it played the mpeg stream.
 > if i force ac3 stream, i got:
 > 
 > A52 sync failed
 > Unknown/missing audio format, using nosound
 > 
 > so, it won't be easy to fix, i think.
 > what header is missing? just that 2 syncbytes, or more?
 > 
 > 
I don't know exactly, it was just a guess. I only know how the AC3
stream in a TS looks like. I haven't taken a look at vdr and how it
transforms the TS. In the TS there is no AC3 header, i.e. the first 4
bytes after the PES header are missing, because the stream id is in
the audio PID of the TS packet and I guess the number of frame headers
and first unit pointer are also not needed. As far as I can see that
would have to be fixed in liba52 or the header bytes would have to be
added before giving it to the library.

Marcus