anchor.diff:      "-Disac=disabled" # depends on `webrtc-audio-coding-1` not compatible with 0.3
       "-Dgs=disabled" # depends on `google-cloud-cpp`
       "-Donnx=disabled" # depends on `libonnxruntime` not packaged in nixpkgs as of writing
  -    "-Dopenaptx=disabled" # depends on older version of `libopenaptx` due to licensing conflict https://gitlab.freedesktop.org/gstreamer/gst-plugins-bad/-/merge_requests/2235
  +    "-Dopenaptx=enabled" # since gstreamer-1.20.1 `libfreeaptx` is supported for circumventing the dubious license conflict with `libopenaptx`
     ]
     ++ lib.optionals (!stdenv.isLinux) [
       "-Dva=disabled" # see comment on `libva` in `buildInputs`
  
positive.code:     libintl
      srt
      vo-aacenc
    ] ++ lib.optionals enableZbar [
      zbar
    ] ++ lib.optionals faacSupport [
  
negative.code: , libxml2
  , srt
  , vo-aacenc
  , libfreeaptx
  , VideoToolbox
  , AudioToolbox
  , AVFoundation
  