[FFmpeg-cvslog] r12894 - in trunk/libavcodec: aac_ac3_parser.c aac_ac3_parser.h aac_parser.c ac3_parser.c

[Justin Ruggles]

Janne Grunau wrote:
> On Saturday 19 April 2008 03:50:41 michael wrote:
>> Author: michael
>> Date: Sat Apr 19 03:50:40 2008
>> New Revision: 12894
>>
>> Log:
>> Change aac and ac3 parsers to use ff_combine_frame().
> 
> this breaks parsing of some AC3 streams. For example 
> ac3_parsing_errors_rev12894.mpg in incoming.
> 
> I'm not sure if this is the actual changeset which is to blame. It is 
> the first which introduces
> "frame sync error" and "incomplete frame" messages. But those are only 
> at the start of the file while the beeps with current trunk are later 
> in the file.
> 
> Playback of that sample is broken from 13579 til 13653. Revision 13654 
> fixes playback but introduces nasty beeps after each frame sync error.
> 
> Janne

I am aware of the issue, and I'm pretty sure I know what's causing it,
but I'm not quite sure how to fix it.  It seems to be occuring when the
first bytes of a frame header are at the end of the buffer.  The next
parser call then has the start of frame as negative, which doesn't seem
to work well with ff_combine_frame().  There was a patch which fixed the
error messages, but didn't fix the problem because the 2 frames end up
being sent in the same packet.

-Justin