title: Convert swf to mp4
body: <p>This answer had not helped: <a href="https://stackoverflow.com/q/20194270/630169">Convert compressed swf to mp4</a>, trying to convert swf file.</p>
  
  <p>ffmpeg output:</p>
  
  <pre><code>$ ffmpeg -i GTDS_demo_new.swf GTDS_demo_new.mp4
  ffmpeg version 2.8.6-1ubuntu2 Copyright (c) 2000-2016 the FFmpeg developers
    built with gcc 5.3.1 (Ubuntu 5.3.1-11ubuntu1) 20160311
    configuration: --prefix=/usr --extra-version=1ubuntu2 --build-suffix=-ffmpeg --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --cc=cc --cxx=g++ --enable-gpl --enable-shared --disable-stripping --disable-decoder=libopenjpeg --disable-decoder=libschroedinger --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librtmp --enable-libschroedinger --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxvid --enable-libzvbi --enable-openal --enable-opengl --enable-x11grab --enable-libdc1394 --enable-libiec61883 --enable-libzmq --enable-frei0r --enable-libx264 --enable-libopencv
    WARNING: library configuration mismatch
    avcodec     configuration: --prefix=/usr --extra-version=1ubuntu2 --build-suffix=-ffmpeg --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --cc=cc --cxx=g++ --enable-gpl --enable-shared --disable-stripping --disable-decoder=libopenjpeg --disable-decoder=libschroedinger --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librtmp --enable-libschroedinger --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxvid --enable-libzvbi --enable-openal --enable-opengl --enable-x11grab --enable-libdc1394 --enable-libiec61883 --enable-libzmq --enable-frei0r --enable-libx264 --enable-libopencv --enable-version3 --disable-doc --disable-programs --disable-avdevice --disable-avfilter --disable-avformat --disable-avresample --disable-postproc --disable-swscale --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libvo_aacenc --enable-libvo_amrwbenc
    libavutil      54. 31.100 / 54. 31.100
    libavcodec     56. 60.100 / 56. 60.100
    libavformat    56. 40.101 / 56. 40.101
    libavdevice    56.  4.100 / 56.  4.100
    libavfilter     5. 40.101 /  5. 40.101
    libavresample   2.  1.  0 /  2.  1.  0
    libswscale      3.  1.101 /  3.  1.101
    libswresample   1.  2.101 /  1.  2.101
    libpostproc    53.  3.100 / 53.  3.100
  [swf @ 0x21cd1e0] Could not find codec parameters for stream 1 (Video: none, none): unknown codec
  Consider increasing the value for the 'analyzeduration' and 'probesize' options
  Input #0, swf, from 'GTDS_demo_new.swf':
    Duration: N/A, start: 0.000000, bitrate: N/A
      Stream #0:0: Audio: mp3, 44100 Hz, mono, s16p, 64 kb/s
      Stream #0:1: Video: none, none, 12 fps, 12 tbr, 12 tbn
  File 'GTDS_demo_new.mp4' already exists. Overwrite ? [y/N] y
  No decoder for stream #0:1, filtering impossible
  Error opening filters!
  </code></pre>
  
  <p>Splitting with <strong>dump-gnash</strong> also does not help: get sound without video after ffmpeg (this answer: <a href="https://stackoverflow.com/a/21023110/630169">https://stackoverflow.com/a/21023110/630169</a>)</p>