[Ffmpeg-devel] segfault in ff_mpeg1_find_frame_end()

[Måns Rullgård]

Stefan Lucke <stefan at lucke.in-berlin.de> writes:

> On Sonntag, 10. April 2005 22:12, M?ns Rullg?rd wrote:
>> Stefan Lucke <stefan at lucke.in-berlin.de> writes:
>> 
>> > On Sonntag, 10. April 2005 20:37, M?ns Rullg?rd wrote:
>
>> >> Can the crash be reproduced using the "ffmpeg" command?
>> >
>> > No, at least not with ffmep -i in_file_name xx.m2v. Are there other
>> > usfull parameters ?
>> 
>> Not really.  Could you put a sample somewhere?
>
> Original sample I got from someone in UK is about 48MB. Tried
> a shorter cut of it (6MB), just a few GOPs before and after a/r switch
> and this one doesnt segfault just:
>
> [mpeg2video @ 0x40615668]invalid mb type in I Frame at 4 0
> [mpeg2video @ 0x40615668]Warning MVs not available
> [mpeg2video @ 0x40615668]concealing 1584 DC, 1584 AC, 1584 MV errors
> [mpeg2video @ 0x40615668]concealing 1584 DC, 1584 AC, 1584 MV errors
> [mpeg2video @ 0x40615668]concealing 1584 DC, 1584 AC, 1584 MV errors

If it doesn't cause the crash, it's not useful for debugging.

>> >> This looks like an unrelated crash.
>> >
>> > But it happens at the same place when aspect ratio changes from 16:9
>> > to 4:3.
>> 
>> All signs are pointing at some buffer misuse.  Could you try running
>> it under valgrind?
>
> Never tried that. Have to read something about that. At least it is
> present on my system:
> stefan at jarada:~> valgrind --version
> valgrind-20030725

That's a very old version.  Get something newer.

-- 
M?ns Rullg?rd
mru at inprovide.com