[Ffmpeg-devel] MPEG2 seeking broken

Steve Lhomme slhomme
Thu Mar 30 15:29:33 CEST 2006

Steve Lhomme wrote:
> Hi
> Michael Niedermayer wrote:
>> Hi
>> On Tue, Mar 14, 2006 at 01:46:35PM +0100, Steve Lhomme wrote:
>>> Hi,
>>> Since nobody is able to reproduce this bug or fix it (I think some 
>>> MPEG data are handled incorrectly, but I am not able to tell what) I 
>>> made a temporary fix to avoid FFMPEG crashing on many (vob) files.
>>> See attached patch. Basically it's to avoid accessing data from a 
>>> NULL pointer. So I guess it's safe to put it in the official FFMPEG 
>>> code. 
>> patch rejected, checking if the ref frame is NULL in the MB loop is
>> not acceptable, check outside and allocate it or disacard the frame
> Given you're the maintainer of the code I assume you can come up with a 
> better patch for that. I have no idea what this thing is about. I just 
> know it's not good to access NULL pointers and that this fixes the bug. 
> I will keep my patch in DrFFMPEG until a 'better' fix comes here.

Here is another version of the patch, out of the inline function (there 
is still a fallback just in case, to avoid crashes). The assert doesn't 
occur anymore in my test files.


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