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• Finding a minimal configuration for ffmpeg

  28 novembre 2022, par Clemens3000

  i am currently developing a video player for Windows and Mac using JUCE and FFmpeg. For this i want to include FFmpeg as a shared library and compile it myself in a minimal configuration to get rid of features and dependencies i don't need. This turns out to be quite difficult, since FFmpeg has a HUGE load of dependencies. And i am pretty new to this compiling game.

  


  Of course i checked all the options for configuration, but there is so many and don't have much knowledge about what all the options actually do. Some are obvious, but many are not.

  


  The minimal configuration i am looking for should enable to playback videofiles encoded with h.264 and it should be LGPL compliant. So just decoding, no encoding.

  


  What i did :

  


  

  • i installed some of the dependencies i might need via macports (under /opt/local)

  


  • i downloaded ffmpeg source code, played around with the configure options and compiled it

  


  • i managed to build my app and it even runs

  


  • i created a configuration with "—disable_everything" and then tried to add features one after another until i build something that works. But that's like finding a needle in the haystack.

  


  


  For Mac my first attempt for this is :
./configure --disable-everything --prefix='../../osx_arm' --install-name-dir='@executable_path/../libs' --extra-ldflags=-Wl,-rpath,'@executable_path/../libs' --enable-version3 --enable-shared --disable-static --enable-swscale --enable-avfilter --enable-libfdk-aac --enable-audiotoolbox --enable-videotoolbox --enable-pthreads --cc=/usr/bin/clang --extra-ldflags=-L/opt/local/lib

  


  I can compile and link my program and as i expected I cannot do much more, which is totally fine for now.

  


  My questions are now :

  


  


  1. How can i find out which configure options are essential to enable simple playback ? How do i find out which options can be discarded ?

     


  


  2. If i run otool on the resulting libs in my current minimal build i still get some dependencies :

     


  


  


  otool -L ../../osx_arm/lib/libavcodec.59.37.100.dylib  ../../osx_arm/lib/libavcodec.59.37.100.dylib: @executable_path/../libs/libavcodec.59.dylib (compatibility version 59.0.0, current version 59.37.100) @executable_path/../libs/libavutil.57.dylib (compatibility version 57.0.0, current version 57.28.100) /opt/local/lib/libiconv.2.dylib (compatibility version 9.0.0, current version 9.1.0) /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1292.100.5) /System/Library/Frameworks/VideoToolbox.framework/Versions/A/VideoToolbox (compatibility version 1.0.0, current version 1.0.0) /opt/local/lib/libX11.6.dylib (compatibility version 11.0.0, current version 11.0.0) /System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation (compatibility version 150.0.0, current version 1775.118.101) /System/Library/Frameworks/CoreMedia.framework/Versions/A/CoreMedia (compatibility version 1.0.0, current version 1.0.0) /System/Library/Frameworks/CoreVideo.framework/Versions/A/CoreVideo (compatibility version 1.2.0, current version 1.5.0) /System/Library/Frameworks/CoreServices.framework/Versions/A/CoreServices (compatibility version 1.0.0, current version 1122.33.0)

  


  Why does FFmpeg actually need libiconv or libX11 ? I believe those don't have to do much with video/audio, right ? Well, I guess FFmpeg needs them anyway...So do i need to compile them myself to and add them to my Application ? I guess later i'll have even more dependencies.

  


  

  3. Any other tips on how to accomplish what i want ?

  


  


• libavcodec/mpeg12dec : Check input for minimal frame size

  4 septembre 2019, par Michael Niedermayer

  libavcodec/mpeg12dec : Check input for minimal frame size
  Fixes : Timeout (35sec -> 6sec)
  
  Fixes : 16901/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MPEGVIDEO_fuzzer-5729024726269952
  
  Fixes : 16901/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MPEGVIDEO_fuzzer-5642388592132096
  Found-by : continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/mpeg12dec.c

• FFmpeg function avformat_open_input for USB video device throws exception : No such file or directory

  8 juin, par ffvideoner

  Windows & C# & FFmpeg.AutoGen

  


  I used the ffmpeg-function (from library FFmpeg.AutoGen) to show video from rtsp-stream :

  


  ffmpeg.avformat_open_input(&pFormatContext, "rtsp://127.0.0.1:8554/abc", iformat, null);


  


  It works right.

  


  Now I want to use this function for USB video device.

  


  FFmpeg outputs this device name :

  


  ffmpeg -list_devices true -f dshow -i dummy

[dshow @ 0000000000163000] "GENERAL WEBCAM" (video)


  


  This is how I'm trying to get the video :

  


  string deviceName = "GENERAL WEBCAM";


  


  or

  


  string deviceName = "video=GENERAL WEBCAM";

ffmpeg.avformat_open_input(&pFormatContext, deviceName, ffmpeg.av_find_input_format("dshow"), null);


  


  For both variants of device names, I get an error :

  


  No such file or directory.


  


  But here it works :

  


  ffmpeg -video_size 1280x720 -framerate 30 -f dshow -i video="GENERAL WEBCAM":audio="Microphone (3- GENERAL WEBCAM)" -c:v libx264 -crf 30 -preset ultrafast ffmpegvideo.mp4


  


  Why doesn't avformat_open_input work with video device name ?