FWIW I tried the “optimize” method, and it did not make any of my 7.1 media playable.
That’s interesting. When I used this setting, it converted my 7.1 TRUEHD audio to 5.1aac.
Im using Chromecast Ultra plugged in to my reciver and all movies worked fines until yesterday when one movie got this error in the middle of the movie. After that all movies with 7,1 doesnt play. The odd thing is that one movie with 7,1 sound worked perfectly fine yesterday but today I cant get it to play anymore.
If I plug my Chromecast Ultra to my bedroom TV with an LG Soundbar all 7,1 movies works fine.
When I plug it back to my recivier with 5,1 soundsystem same movie doesnt play anymore(7,1 movie).
Is it the reciver or is it the chromecast ultra. It definitly is the 7,1 who is screwing something.
I was getting the h4 error with HEVC AAC 7.1 on my Chromecast Ultra.
I finally resolved it by changing the Chromecast.xml profile to the one in this github: https://github.com/lukegackle/Plex-Media-Server-Chromecast-XML-profile
This will most likely screw over some Direct Play stuff and I left the resolutions at 1920x1080 as I have a 1080P TV.
Anyway - give it a go, even as a test.
2 Likes
With that profile in place, 1080p H.265 7.1 files now play straight way.
However, I skipped to 50% in the file and it stopped (was just “buffering”).
I tried restarted the stream from the start again, letting it play for 10 seconds, then skipped to 50% and it skipped just fine.
Better than it used to be!
Thank you 
It’s been 7 months since this was first reported and still not even a comment from a Plex dev. This is driving me crazy. Half of my media is now unplayable on any of the 4 CCU’s in my house.
Not quite sure why I’m still paying for Plex seeing as I’ve been forced back to Kodi.
Very disappointing.
2 Likes
Agree. Have had the same issue as you all since my stupid chromecast updated.
And I paid for plex app the day before it happened.
How can it possibly be that hard to work with a google rep to get this fixed.
I would have been fired from my job 10x over if I didn’t respond to paying customer complaints like all the above, that plex seems to be ignoring for some unknown reason.
Very bizarre.
Getting the same Error code: h4 (Not Supported) error.
Opened a thread and really hoping this can be fixed.
I’ve been messing with custom Chromecast.xml modifications, but it doesnt seem to help.
Plex Devs, please help us!
I also have this issue. And my files did not start working after optimising. I have AAC and AC3 7.1
Other files work fine. I’ve also had issues with Dolby TruHD, especially on 4K content.
please fix this, damn.
1 Like
Sorry this was left with no reply for so long!
We actually have this logged internally for quite some time but even now the limitations of the Cast SDK don’t really provide enough info on the device playback capabilities! They list the codec support but not channels 
That said we still have the issue open in hopes this changes or we find another way but we have to be honest and say this is likely not gonna have a fix soon!
If this changes I’ll keep you posted!
As a work around replacing the Profile for those of you who have the Ultra should work! (Please be advised though that it can break playback for other Casting devices)
I’m sorry to come here only to give bad news
4 Likes
Thank you for your reply. Much appreciated. Bad news is better than no news. At least we know what we can expect.
I noticed today that a movie would stream well on another tv in my house with another Chromecast when I was troubleshooting this. The two Chromecast seems to be of same type so I decided to switch them on the two TV´s. None of them will play this movie on my newest Samsung-TV, but both works on the oldest Samsung-TV.
That made me look at my newest TV. I went into settings->Sound->Expert Settings and under HDMI Input Audio Format I changed the default value from ´Bitstream´ to ´PCM´. And then I got rid of the H4 error code and was able to play the movie I was struggling with.
I tried to switch the settings on the TV back to ´Bitstream´ and the problem occurred again.
Hope this information can be useful to some of you.
@mikec_pt Maybe you should ask Emby how they do it 
It works just fine with their server…
Forcing the audio to be transcoded to PCM shouldn’t need to be the solution. The chromecast should be able to pass through the audio to your TV or reciever
Can you explain how to do this?
Sure.
- find the directory where your plex data lives (https://support.plex.tv/articles/202915258-where-is-the-plex-media-server-data-directory-located/)
- Inside this there’s a
Plex Media Serverdir where Logs/Metadat/Cache etc live; create a dir namedProfileshere. - Place the Chromecast.xml file shared above in there, or create your on if you know what your doing.
Profiles placed in the “application support” or “plex data dir” always override the ones in the install dir that we ship.
This in very handy but do use with care since you can also break Playback. I.E. the profile above is confirmed by others users to work with the Chromecast Ultra, but might break playback for all other Cast devices.
2 Likes
Hi Mike,
It seems to me that something in the above chromecast.xml should force plex to transcode the audio so we don’t get the error anymore. Could you elaborate as to what setting is making the audio to be transcoded.
In my family I’m the only one using the Ultra, I would like to try edit this stuff without breaking playback on the other chromecasts. If that isn’t possible the only solution I can see is running 2 Plex servers, one for me with an edited xml and one for the rest of the family.
Cheers
The original Profile does force it to transcode:
<TranscodeTargets>
<VideoProfile protocol="http" container="mkv" codec="h264" audioCodec="aac,mp3" context="streaming" />
<MusicProfile container="mkv" codec="opus" />
<PhotoProfile container="jpeg" />
<SubtitleProfile container="ass" codec="ass" />
</TranscodeTargets>
See that here both aac and mp3 are listed, but you also have to look into the actual code config:
<VideoAudioCodec name="aac,mp3">
<Limitations>
<UpperBound name="audio.channels" value="2" />
</Limitations>
</VideoAudioCodec>
So tl;dr when we transcode we force only 2ch because that’s what most Chromecast devices support and I believe that’s what other software’s are doing actually!
I’m not quite sure yet why the Ultra doesn’t like that, but its also true the correct solution is to let it direct play since it should be capable.
Also Profiles are not the first thing we look into, most of or players have their own media decision engine, they try to find the info about what’s best and tell it to the server, but in this case Goolge SDK doesn’t tell us “hey this device supports 8 channels” (https://developers.google.com/cast/docs/media#audio_passthrough as you can see its just the codecs).
If it did we could say “Hey server this guy can play 7.1, so let it do it”;
Failing that option Profiles can actually be different for some devices even if the “platform/OS” is the same; i.e we have different profiles for different iPhones etc.
But even here the SDK doesn’t not provide enough info to identify the the target device (or so it seems, we are still looking into that and trying to find some hidden way of doing it that, but its not very likely this will happen much less soon) so this rules out the option of having separate profiles!
Last but not the least we still have an open issue where we are also trying to investigate why we do get an error (we can reproduce this) when transcoding on the Ultra and not on the others, in theory even if transcoding is not the best solution it should work and it might end up being the only solution we have!
In retrospect my post wasn’t clear on that; we will try the best solution if we can but failing that transcoding should work, unless there’s yet another goolge quirk about this device.
This is why for those of you who do have only have the Ultra, the change of the Profile is the for now the best work around, but ofc it would be if there’s more Chromecasts (expect for the Shield Pro, If I’m not mistaken this one should support it too).
So to conclude we are looking into this and I just ask again for some patience with this one. I will keep you posted with future developments.
1 Like
Would any of you that have a “AAC 7.1” working with DirectPlay via the altered Profile be able to sent (DM) me a sample of such file?
