anchor.diff:      (enableFeature (if isLinux then libdc1394 != null && libraw1394 != null else false) "libdc1394")
       (enableFeature (libiconv != null) "iconv")
       #(enableFeature (if isLinux then libiec61883 != null && libavc1394 != null && libraw1394 != null else false) "libiec61883")
  -    (enableFeature (if isLinux then libmfx != null else false) "libmfx")
  +    (enableFeature (if isLinux && !isAarch64 then libmfx != null else false) "libmfx")
       (enableFeature (libmodplug != null) "libmodplug")
       (enableFeature (libmysofa != null) "libmysofa")
       #(enableFeature (libnut != null) "libnut")
  
positive.code:  *   libvpx(stable 1.3.0) openal openjpeg pulseaudio rtmpdump samba vid-stab
   *   wavpack x265 xavs
   *
   * Not supported:
   *   stagefright-h264(android only)
   *
  
negative.code: , libXv ? null # Xlib support
  , libXext ? null # Xlib support
  , lzma ? null # xz-utils
  , nvenc ? !stdenv.isDarwin && !stdenv.isAarch64, nv-codec-headers ? null # NVIDIA NVENC support
  , openal ? null # OpenAL 1.1 capture support
  #, opencl ? null # OpenCL code
  , opencore-amr ? null # AMR-NB de/encoder & AMR-WB decoder
  