[MPlayer-dev-eng] ogg demuxer

[Gabriel Gerhardsson]

Hi Alban

I would very much like to try the new ogg container support.
Could you please send a patch of your work to the list or if it's to big
or something, to me directly. It would be greatly appreciated.

Take care
/Gabriel

On Thu, 2002-03-14 at 19:24, Alban Bedel wrote:
> Hi Arpi,
> 
> on Thu, 14 Mar 2002 18:36:34 +0100 you wrote:
> 
> > Hi,
> > 
> > Is the ogg demuxer working? Why isn't it in the CVS yet then?
> > There are several test files at mphq, and i also can help testing
> > it and fixing a-v sync problems if any
> > 
> 
> Actually, I make a little pause on mplayer but the Ogg demuxer is about ready.
> It seems to work (still no seeking) but I runned into trouble with vorbis audio.
> Because unlike VBR mp3 vorbis don't have fixed length (in time) packet, and I
> don't know how to handle this.
> BTW I also did a ahead decoding stuff a little different from Nick's version.
> In this version I use only decoded audio to get the PTS and ogg movies work
> good, sync is allrigth (and more viewable as framedropping is smarter, but that's
> not the topic ;)
> I think the problem with really vbr audio come from the timestamp correction. I didn't
> fully understand how it work nor what it should do (I read the tech docs, but didn't
> understand all). In my ahead decoding version there is no timestamp correction
> and I still have perfect sync (but not tested with many files). The only real
> difference is that in mplayer the audio timer is increased each time some audio is
> writed to the soudcard : timer += playsize/ sh_audio->o_bps (where
> playsize is the length in bytes of writed data) while I keep a counter of total
> writed bytes and get the time from it : 
> played_bytes += playsize; timer = played_bytes / sh_audio->o_bps;
> I first did like in mplayer but after some minutes slowly the audio was going out of sync.
> And I found that it was the rounding error, so my question is does the timestamp
> correction just correct this or also something else ?
> I'd like that we find a good way to handle this. If possible we should get audio PTS
> only from decoded data. For seeking I don't know, but imho we should avoid
> calculating PTS using the compressed data as much as possible.
> That's it the demuxer seems ready but it's actually unusable with vorbis audio :(
> 	Albeu
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