anchor.diff:    ];
   
     buildInputs = [
  -    ffmpeg
  +    ffmpeg_3
       glib
       gst-plugins-base
       gstreamer
  
positive.code: , meson
  , ninja
  
  , ffmpeg
  , glib
  , gst-plugins-base
  , gstreamer
  
negative.code:   postUnpack = /* gst-libav vendors outdated ffmpeg sources */ ''
      pushd $srcRoot/gst-libs/ext/
        rm -rfv libav/
        tar -xf ${ffmpeg_3.src}
        mv -v ffmpeg-*/ libav/
      popd
    '';
  