anchor.diff:      libogg-dev \
       libtheora \
       libtheora-dev \
  -#    libvpx \
  -#    libvpx-dev \
       libvorbis \
       libvorbis-dev \
  -#    libwebp \
  -#    libwebp-dev \
       nasm \
       openssl \
       openssl-dev \
  
positive.code:   --enable-gpl \
    --enable-nonfree \
    --enable-small \
  # audio: mp3 codec
    --enable-libmp3lame \
  # video: h264 codec
  #  --enable-libx264 \
  # video: h265 codec
  #  --enable-libx265 \
  # video: vp9 codec
  #  --enable-libvpx \
    --enable-libtheora \
  # audio: ogg vorbis codec
    --enable-libvorbis \
  # audio: opus codec
    --enable-libopus \
  # audio: aac codec (high quality, nonfree)
    --enable-libfdk_aac \
  #  video: subtitle renderer
  #  --enable-libass \
  # image: webp format support
  #  --enable-libwebp \
  # streaming: RTPM streaming protocol
  #  --enable-librtmp \
  # video: postprocessing
  #  --enable-postproc \
  
  # audio: resampling
    --enable-avresample \
    --enable-libfreetype \
    --enable-openssl \
  
negative.code:     freetype-dev \
      lame \
      lame-dev \
      libogg \
      libvpx \
      libogg-dev \
  