Chromecast Ultra with Plex Media Server

Chromecast.xml

<?xml version="1.0" encoding="utf-8"?>
<Client name="Chromecast">
  <TranscodeTargets>
    <VideoProfile protocol="http" container="mkv" codec="h264,hevc" audioCodec="eac3,ac3" subtitleFormat="ass,srt" context="streaming"/>
    <SubtitleProfile container="ass" codec="ass" context="all" />
  </TranscodeTargets>
  <DirectPlayProfiles>
    <VideoProfile container="mp4" codec="hevc,mpeg1video,mpeg2video,h264,mpeg4" audioCodec="eac3,ac3,mp3,mp2"/>
    <VideoProfile container="mkv" codec="vp9,hevc,mpeg1video,mpeg2video,h264,mpeg4" audioCodec="eac3,ac3,mp3,mp2,pcm,flac,alac,truehd" subtitleFormat="ass,srt"/>
    <MusicProfile container="mp3" codec="mp2,mp3"/>
    <MusicProfile container="ac3" codec="ac3"/>
    <MusicProfile container="mp4" codec="aac"/>
    <MusicProfile container="flac" codec="flac"/>
    <MusicProfile container="wav" codec="pcm"/>
    <PhotoProfile container="jpeg,png,gif"/>
  </DirectPlayProfiles>
  <CodecProfiles>
    <VideoCodec name="*">
      <Limitations>
        <UpperBound name="video.width" value="3840"/>
        <UpperBound name="video.height" value="2176"/>
        <UpperBound name="video.bitrate" value="75000"/>
      </Limitations>
    </VideoCodec>
    <VideoAudioCodec name="ac3,eac3">
      <Limitations>
        <UpperBound name="audio.channels" value="6"/>
      </Limitations>
    </VideoAudioCodec>
  </CodecProfiles>
</Client>

Note that the Chromecast Ultra cannot play AAC streams with more than two channels. That is true regardless of whether you have it decode the stream or pass it on to a sound receiver. In this solution, we let the Plex server transcode multi-channel AAC to AC3, which is efficient and sounds good.

Fixed an issue with playing subtitles. With this version, playing a video with external SRT subtitles work. However, embedded subtitles do not.