[Ffmpeg-devel] [BUG] H.264 crash

[Måns Rullgård]

Diego Biurrun said:
> On Wed, Jan 18, 2006 at 09:57:57PM +0100, Diego Biurrun wrote:
>>
>> I have a sample here that makes the H.264 decoder (MPlayer, MPlayer with
>> lavf demuxer, xine, vlc, ffplay) crash with the following message:
>>
>> [h264 @ 0x106463c8]reference picture missing during reorder
>> [h264 @ 0x106463c8]reference picture missing during reorder
>> [h264 @ 0x106463c8]reference picture missing during reorder
>> mplayer: h264.c:2610: mc_dir_part: Assertion `pic->data[0]' failed.
>>
>> Get the sample from here:
>>
>> ftp://sandman.homedns.org/diego/ffmpeg/killbillclip.avi
>>
>> The crash happens both on my G4 (Debian unstable, gcc 4.0.3) and on my K6
>> (Debian stable, gcc 2.95.4), so it's not platform dependent.
>>
>> The sample may very well be a broken bitstream, but a crash is bad
>> nevertheless.  If you need the backtrace I'll gladly provide it.
>
> Loren confirmed this to be due to broken bitstream.  Not crashing would
> nevertheless be good.

Crashes like that happen whever a reference picture is missing.  In a correct
bitstream this should obviously never happen.  However, in sitations where
packet loss is likely (UDP, DVB, etc.), pictures will be missing, and crashing
is totally unacceptable.  It also makes seeking in index-less files practically
impossible.

A long time ago, before lavc supported H.264 with B-frames, this did not cause
a crash, only producing a few garbled frames like the other codecs do.  Is
there something that makes it particularly difficult to fix this problem?

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