anchor.diff:      ++ stdenv.lib.optional x264Support x264
       ++ stdenv.lib.optional xvidSupport xvidcore
       ++ stdenv.lib.optional vdpauSupport libvdpau
  -    ++ stdenv.lib.optional faacSupport faac;
  +    ++ stdenv.lib.optional faacSupport faac
  +    ++ stdenv.lib.optional dc1394Support libdc1394;
   
     enableParallelBuilding = true;
       
  
positive.code: , xvidSupport ? true, xvidcore ? null
  , vdpauSupport ? true, libvdpau ? null
  , faacSupport ? false, faac ? null
  }:
  
  assert speexSupport -> speex != null;
  
negative.code:     ++ stdenv.lib.optional x264Support "--enable-libx264"
      ++ stdenv.lib.optional xvidSupport "--enable-libxvid"
      ++ stdenv.lib.optional vdpauSupport "--enable-vdpau"
      ++ stdenv.lib.optional faacSupport "--enable-libfaac --enable-nonfree"
      ++ stdenv.lib.optional dc1394Support "--enable-libdc1394";
  
    buildInputs = [ pkgconfig lame yasm zlib bzip2 ]
      ++ stdenv.lib.optional mp3Support lame
  