anchor.diff:  , libxml2
   , srt
   , vo-aacenc
  +, libfreeaptx
   , VideoToolbox
   , AudioToolbox
   , AVFoundation
  
positive.code:     "-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
    ]
    ++ lib.optionals (!stdenv.isLinux) [
      "-Dva=disabled" # see comment on `libva` in `buildInputs`
  
negative.code:     libintl
      srt
      vo-aacenc
      libfreeaptx
    ] ++ lib.optionals enableZbar [
      zbar
    ] ++ lib.optionals faacSupport [
  