[xine-devel] Re: ac3 breakage (potentially avi specific)

[James Courtier-D. <Ja...@su...>]

Heiko Schaefer wrote:
> Hi James, everyone,
> 
> I am experiencing trouble with avi streams that contain ac3 audio.
> 
> there are two effects:
> 1) for some streams xine used to crash (before james committed a
>    workaround for that)
It was not a workaround, it was a bug fix.

> 2) for all streams i tried, playback is jumpy, sync is messy and the sound
>    skips every once in a while
> 
> after some digging, i found that the problem started appearing because of
> the commit in src/liba52/xine_decoder.c after rev 1.50 (1.50 was still
> ok). rev 1.51 is badly broken for me. rev 1.52 fixes the crash situation,
> but playback is still broken (see above).
> 
> i have looked at the diff between 1.50 and 1.51 for some time and it is
> just too big (and contains too many magic numbers) for me to mentally
> parse without knowing the first thing about a52.
> 
> could you please look into that, james? the current situation is not
> acceptable - and i would strongly advise against making any more releases
> with that issue in them (beta 12 contains the bug - and rev 1.52 doesn't
> really solve it, it just masks the crash, which apparently has some
> different, underlying reason).
> 
> maybe it would even make sense to roll back liba52/xine_decoder.c to 1.50
> for the time being?
> 
> Heiko
> 
I think the problem is actually in the avi demuxer.
liba52 now has to have an accurate buf->size value.
I don't think the avi demuxer is filling in this field correctly, but as 
I know nothing about .avi, can someone else please confirm this or not.
In the mean time, I will look into another possible bug in liba52.
Once I have confirmed that the .avi demuxer is in fact sending correct 
information, I will be more confident that we have a final fix.

Can someone also post a url for a .avi stream that shows the above problems.

Cheers
James