Thanks for looking into this, Hopefully you will find the problem and the fix.
JohnB
Hi MovieFan.Plex
How did you go with the devs? do you need more logs or for me to try something else?
JohnB
I donât have any definitive answer yet. We havenât been able to identify the underlying problem. What I saw was that the app was reporting different audio capabilities. The app checks to see what codecs are supported by your device, then checks what is supported on the connected device through hdmi. There are some conflicting results and I think this is causing the app to do the wrong thing.
It appears that your device only support 2 channel AC3, but it supports multi-channel PCM. So we should be transcoding the audio from 5.1 AC3 to 5.1 PCM, but itâs not doing it. It is just trying to play the 5.1 AC3 and failing, which is why you get no sound. A device trying to play an unsupported audio can result in choppy video, so your symptoms fit. Iâm looking to see why it chose to play the audio instead of transcoding it.
Thank you for you great explanation,
I think I may have found the problem, Plex assumes that I am using the hdmi for the audio but I am using the devices optical audio port for my 5.1 AC3 to the surround sound system.
I have turned on in the device audio pass-through and the audio set to go to the optical port.
Kodi is installed with 5.1 AC3 turned on in Kodi and it passes the 5.1 AC3 to the surround sound system with no problem.
Looking forward to your reply. JohnB
Kodi hand;es pass-through differently than our app. They do everything in software and donât rely on hardware at all, where as we do.
Iâm still looking into this issue.
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Thanks MovieFan.Plex
In plexâs forum there are lot of people are having trouble with AC3 pass-through, I think Plex may have to use software and not rely on hardware to fix these on going problems across devices.
Plex relying on the hardware of the device seems to be the problem.
I think Plex need to have a good look at Kodi way of doing software and follow.
Looking forward to your reply. JohnB
What Iâve noticed is the problem occurs on Android 7.1+ while it works with the same video on Android 6 (in my case). Just bought a Minix U9 and playing around with the different roms available and bot Android TV 7.1 as default Minix OS 7.1 have a problem while the âolderâ version of Android TV and Stock Minix work perfect.
I use Kodi Plex plugin as a temporary workaround. Hope it will be fixed soon as I like original Plex Player a lot more 
Same issue in my m8s pro, please fix it
This also happens with my x96 android tv box. Plex refuses to play any ac3 audio - the VLC android app works correctly.
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Any news on this issue @anon18523487 ?
I also have issues playing mkv or mp4 with AC3 or AAC.
Mecool M8s Pro L Android 7.1.
DTS works fine.
EDIT: SOLVED
After changed the sound preferens in the Android box and choosed Surround to ALWAYS, then the AC3 playbacks without an issue in PLEX. Hope this will help others.
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@molle83, unfortunately not, I changed the sound option âSurroundâ to âAlwaysâ on my box and while the video plays, I cannot hear any audio 
@anon18523487 any news on this ?
Below the sorround âalwaysâ, i have Digital sound= hdmi raw.
In plex i have settings show in the pictures.
My reciver is set to output surround Dolby digital/dts
Plex Media Server version 1.14.0.5470.-9d51fdfaa running on synology ds 214 play DSM 6.2.1-23824 Update 1.
Did you ever provide me logs?
I have had a similar issue and have posted a client log here: No playback for media with ac3: connection to server lost
It seems to crash exoplayer when ac3 support fails to initialize. Then the error with âconnection lostâ appears on the client. Tested a few old android 4.1 and 5.1 that has this issue and found no fix. It should fallback to aac/pcm in my mind.
My apologies, I did not mean to be rude, I just wondered if you had any update in general on the matter.
Attached are my logs, the movies with AC3 are âMingle All the Wayâ and âCruiseâ.
Both were able to run, but without any audio.
Sorry, I should have been more clear. I need the log from the Android app after you try playing back a video with ac3 audio.
I had found an issue before related to some of these Android boxes running Realtek SOCs. They claim they support multi channel AC3, but sometimes they really donât or they implemented it in a way that it doesnât work with Plex. Plex checked through the OS what audio formats are supported, the device then reports back, and Plex follows what it is told. If it gets told the wrong thing, then things donât work right. I need your logs to see if this is a similar situation.
Ha, indeed that makes sense.
Attached are the logs of my Android Box (A95XPro), the failing movie is âMingle all the wayâ, played around 12:00 On December 9.
Thanks for looking into this !plex android box logs.txt (1.1 MB)
Hi @anon18523487 ! any news on this ? Itâs still a very annoying issue : I need to manually convert every file
