[FFmpeg-trac] #2501(FFmpeg:new): FFMPEG subtitles filter segfaults with matroska files

[FFmpeg]

#2501: FFMPEG subtitles filter segfaults with matroska files
-------------------------------------+-------------------------------------
             Reporter:  klaxa        |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:  FFmpeg       |                  Version:  git-
             Keywords:  subtitles    |  master
  videofilter segmentation fault     |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug: FFMPEG crashes when trying to use the videofilter
 "subtitles" with matroska files that contain subtitle tracks.
 How to reproduce: Encode a video with a the "subtitles" videofilter and
 use a matroska file as the subtitle file argument
 {{{
 % ffmpeg -i input ... outputffmpeg -i hataraku.mkv -c:a libmp3lame -c:v
 mpeg4 -sn -vf "subtitles=hataraku.mkv" -t 60 hataraku_hardsub.mkv

 ffmpeg version N-52453-g12e3c1b Copyright (c) 2000-2013 the FFmpeg
 developers
   built on Apr 25 2013 00:02:29 with gcc 4.8.0 (GCC)
   configuration: --prefix=/home/klaxa/ffmpeg/build --disable-debug
 --disable-static --enable-avresample --enable-dxva2 --enable-fontconfig
 --enable-gpl --enable-libass --enable-libbluray --enable-libfreetype
 --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-
 libopencore_amrnb --enable-libopencore_amrwb --enable-libopenjpeg
 --enable-libopus --enable-libpulse --enable-librtmp --enable-
 libschroedinger --enable-libspeex --enable-libtheora --enable-libv4l2
 --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxvid
 --enable-postproc --enable-runtime-cpudetect --enable-shared --enable-
 vdpau --enable-version3 --enable-x11grab
   libavutil      52. 27.100 / 52. 27.100
   libavcodec     55.  6.100 / 55.  6.100
   libavformat    55.  3.100 / 55.  3.100
   libavdevice    55.  0.100 / 55.  0.100
   libavfilter     3. 60.101 /  3. 60.101
   libavresample   1.  1.  0 /  1.  1.  0
   libswscale      2.  2.100 /  2.  2.100
   libswresample   0. 17.102 /  0. 17.102
   libpostproc    52.  3.100 / 52.  3.100


 }}}
 Patches should be submitted to the ffmpeg-devel mailing list and not this
 bug tracker.

 I attached ffmpeg output with high log level, gdb output and valgrind
 output. Interestingly with valgrind ffmpeg does not segfault, but slowly
 proceeds to encode and produces the desired result, because of valgrind
 horribly slow though.

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/2501>
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