[MPlayer-users] Re: random segfaults while encoding (local VOBs, lavc)

[Corey Hickey]

Vitezslav Kotrla wrote:
>> I did some lavc encode instead of x264 and now this is really spooky
>> as mencoder segfaults _randomly_, sometimes spitting error
> 
> Well, I did another rigorous debugging: no more ripped VOBs - this time
> I took my trusty Kurosawa's Ran disc and run encode directly on DVD data.
> 
> Segfault once again.
> 
> Running in gdb yields
> 
> (gdb) run dvd:// -nosound -ovc lavc -lavcopts vcodec=mpeg4 -o test.avi
> Starting program: /usr/local/bin/mencoder dvd:// -nosound -ovc lavc -lavcopts vcodec=mpeg4 -o test.avi
> [Thread debugging using libthread_db enabled]
> [New Thread 47405525323408 (LWP 26887)]
> MEncoder dev-SVN-r21363-4.1.2 (C) 2000-2006 MPlayer Team
> CPU: AMD Athlon(tm) 64 X2 Dual Core Processor 4200+ (Family: 15, Model: 43, Stepping: 1)
> ...
> 1 duplicate frame(s)!
> [mpeg4 @ 0xbb3c70]Error evaluating rc_eq "tex^qComp"b  A-V:0.000 [0:0]
> Pos:   0.4s      9f ( 0%)  0.00fps Trem:   0min   0mb  A-V:0.000 [0:0]
> 1 duplicate frame(s)!
> [mpeg4 @ 0xbb3c70]Error evaluating rc_eq "tex^qComp"6mb  A-V:0.000 [818:0]
> Pos:  58.3s   1456f ( 0%) 104.79fps Trem:  45min 1126mb  A-V:0.000 [817:0]
> 1 duplicate frame(s)!
> [mpeg4 @ 0xbb3c70]Error evaluating rc_eq "tex^qComp"5mb  A-V:0.000 [816:0]
> Pos:  60.8s   1517f ( 0%) 104.32fps Trem:  45min 1114mb  A-V:0.000 [815:0]
> 1 duplicate frame(s)!
> Pos:  61.4s   1532f ( 0%) 104.15fps Trem:  45min 1118mb  A-V:0.000 [819:0]
> Program received signal SIGSEGV, Segmentation fault.
> [Switching to Thread 47405525323408 (LWP 26887)]
> 0x000000000063afb0 in ff_estimate_p_frame_motion (s=0xd5b100, mb_x=24, mb_y=1) at ../libavutil/internal.h:143
> 143         if(a<128) return ff_sqrt_tab[a];

Since this is segfaulting within an ffmpeg library, you should probably 
report this to the ffmpeg-devel mailing list. First, however, you must 
provide a sample source video with which you can reproduce the segfault.

1. Run 'mplayer dvd://1 -dumpstream'
2. You can kill the process once you think it's dumped enough.
3. Use dd to trim down stream.dump. Keep trying until you have a file 
that is nearly the smallest possible yet still reproduces the segfault.
4. Upload the file to ftp://upload.mplayerhq.hu/MPlayer/incoming/
5. Include the name of the file you just uploaded in your bugreport to 
ffmpeg-devel.

-Corey