anchor.diff:      sha256 = "03clkknaq3mz84p85cvr21gsy9b8vv2g4vvyfz44hz8la253jfqi";
     };
   
  -  patched_libav_12 = libav_12.overrideAttrs (super: {
  -    patches = (super.patches or []) ++ [(
  -      # NOTE: 2018-04-26: HandBrake compilation (1.1.0) requires
  -      # a patch of LibAV (12.3) from HandBrake team. This patch
  -      # not went LibAV upstream.
  -      fetchurl {
  -        url = ''https://raw.githubusercontent.com/HandBrake/HandBrake/9e1f245708a157231c427c0ef9b91729d59a30e1/contrib/ffmpeg/A21-mp4-sdtp.patch'';
  -        sha256 = "14grzyvb1qbb90k31ibabnwmwnrc48ml6h2z0rjamdv83q45jq4g";
  -      })
  -      # NOTE: 2018-11-11: Transcoding to MP4 can fail with:
  -      #
  -      # Tag avc1/0x31637661 incompatible with output codec id '28'
  -      # muxavformat: avformat_write_header failed!
  -      #
  -      # Fix using Handbrake patch that is not upstream in libav.
  -      (
  -      fetchurl {
  -        url = ''https://raw.githubusercontent.com/HandBrake/HandBrake/df6c26fa261423237ee2bec0bf784c32cbfda3fa/contrib/ffmpeg/A20-avc3-hvc1-override.patch'';
  -        sha256 = "1vijd7bmkzp3sb6zhpcpdni8fz4h13wgglnml6cz9f44j41w2c3v";
  -      })
  -    ];
  -  });
  -
     nativeBuildInputs = [
  -    python2 pkgconfig yasm autoconf automake libtool m4
  -  ] ++ lib.optionals useGtk [ intltool wrapGAppsHook ];
  +    python2 pkgconfig autoconf automake yasm libtool m4
  +  ] ++ lib.optionals useGtk [ wrapGAppsHook intltool ];
   
     buildInputs = [
       fribidi fontconfig freetype jansson zlib
       libass libiconv libsamplerate libxml2 bzip2
  -    libogg libopus libtheora libvorbis libdvdcss a52dec libmkv
  -    lame libdvdread libdvdnav libbluray mp4v2 mpeg2dec x264 x265 libvpx
  +    ffmpeg_4 libtheora x264 x265 libvpx mpeg2dec
  +    libopus lame libvorbis a52dec
  +    libogg libmkv mp4v2
  +    libdvdread libdvdnav libdvdcss libbluray
     ] ++ lib.optionals useGtk [
       glib gtk3 libappindicator-gtk3 libnotify
       gst_all_1.gstreamer gst_all_1.gst-plugins-base dbus-glib udev
       libgudev hicolor-icon-theme
  -  ] ++ (if useFfmpeg then [ ffmpeg ] else [ patched_libav_12 ])
  -  ++ lib.optional useFdk fdk_aac;
  +  ] ++ lib.optional useFdk fdk_aac;
   
     enableParallelBuilding = true;
   
  
positive.code: # Upstream distributes HandBrake with bundle of according versions of libraries and patches to them.
  #
  # Derivation patches HandBrake to use our closure.
  #
  
  { stdenv, lib, fetchurl,
    python2, pkgconfig, yasm, zlib,
    autoconf, automake, libtool, m4, jansson,
    libass, libiconv, libsamplerate, fribidi, libxml2, bzip2,
    libogg, libopus, libtheora, libvorbis, libdvdcss, a52dec,
    lame, libdvdread, libdvdnav, libbluray,
    mp4v2, mpeg2dec, x264, x265, libmkv,
    fontconfig, freetype, hicolor-icon-theme,
    glib, gtk3, intltool, libnotify,
    gst_all_1, dbus-glib, udev, libgudev, libvpx,
    useGtk ? true, wrapGAppsHook ? null, libappindicator-gtk3 ? null,
    useFfmpeg ? false, libav_12 ? null, ffmpeg ? null,
    useFdk ? false, fdk_aac ? null
  }:
  
  stdenv.mkDerivation rec {
    # TODO: Release 1.2.0 would switch LibAV to FFmpeg.
    version = "1.2.0";
    name = "handbrake-${version}";
  
  
negative.code:     (if useFdk then "--enable-fdk-aac"            else "")
    ];
  
    # NOTE: 2018-12-27: Check NixOS HandBrake test if changing
    NIX_LDFLAGS = [
      "-lx265"
    ];
  