anchor.diff:  RUN cd /tmp/ \
      && wget https://github.com/nkari82/mp4v2/archive/master.zip \
      && unzip master.zip \
  +   && rm master.zip \
      && cd mp4v2-master \
      && ./configure && make && make install && make distclean && rm -rf /tmp/*
   
   RUN cd /tmp/ \
      && wget https://github.com/nu774/fdkaac/archive/1.0.0.tar.gz \
      && tar xzf 1.0.0.tar.gz \
  +   && rm 1.0.0.tar.gz \
      && cd fdkaac-1.0.0 \
      && autoreconf -i && ./configure && make && make install && rm -rf /tmp/*
   
  -RUN wget https://github.com/sandreas/m4b-tool/releases/download/v.${M4B_TOOL_VERSION}/m4b-tool.phar -O /usr/local/bin/m4b-tool && chmod +x /usr/local/bin/m4b-tool
  +RUN wget https://github.com/sandreas/m4b-tool/releases/download/v.${M4B_TOOL_VERSION}/m4b-tool.phar -O /usr/local/bin/m4b-tool \
  +    && chmod +x /usr/local/bin/m4b-tool
   
   CMD ["/bin/sh"]
  
positive.code:     freetype-dev \
      lame \
      lame-dev \
      libass \
      libass-dev \
      libogg \
      libvpx \
      libogg-dev \
  
negative.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 \
  