TrueHD passthrough issues on Shield TV 3.2 (Android 6.0)

[vpulim]

I have a brand new, vanilla Shield TV running the latest OS update (3.2) and SPMC 16.4.2. DD and DD+ both passthrough fine using the Shield TV + SPMC, but I can't get TrueHD passthrough working. When I try playing a TrueHD movie, I hear no audio and the video playback stutters and freezes constantly.

My AVR is a Samsung HW-K950 soundbar that supports DD, DD+, TrueHD and Atmos. .

TrueHD & Atmos passthrough work fine with the same soundbar when I use Kodi v17 running on my kodibuntu Intel NUC box.

I've attached a debug log from a sample session demonstrating the issue.

In this example, I tried playing an Atmos demo video over TrueHD (audio track #1) but I hear no audio through my soundbar and experience video stuttering. However, when I select the DD+ track (audio track #3), my soundbar detects Atmos and audio plays back fine. Again, both tracks play fine through the soundbar when I use my Intel NUC box running Kodi v17.

Also, when I try running Kodi v17 (beta and nightlies) on the Shield TV, I experience the same issue with TrueHD not passing through. However, I don't experience the video stuttering.

spmc.log.zip

[vpulim]

After further testing of TrueHD decoding with my Onkyo NR626 receiver I discovered the following:

Shield TV + Onkyo NR626 = OK
Shield TV + Samsung K950 = Fail
Kodibuntu + Onkyo NR626 = OK
Kodibuntu + Samsung K950 = OK

So, it looks like SPMC (or Android) is packing the TrueHD stream differently from Kodibuntu and the resulting stream is handled properly by the Onkyo, but not the Samsung K950. The stream generated by Kodibuntu plays fine on both devices.

[heymoe]

Not sure what to tell you. I'm running a Shield TV v3.2 with SPMC v16.4.2. I'm not using a Samsung K950 but a Anthem MRX-720 receiver in a 7.1.4 Atmos setup and can confirm that TrueHD + Atmos does work in my setup.

[heymoe]

Have you enabled Expert mode in setup and made sure TrueHD enabled as being supported by your receiver / soundbar? Also maybe try using the Android, Raw device for the Passthrough device if you haven't already.

[vpulim]

Yes, all my settings are correct. As I mentioned above, I am able to play TrueHD just fine using the Shield TV with my Onkyo NR626. I tried Android, Raw and Android, IEC.

I think it is a combination of the Shield TV (or Android 6.0) packing the TrueHD stream in a certain way, and the Samsung K950 not being robust enough to handle that packing. What is strange is that the K950 can handle TrueHD just fine from my Intel NUC Kodibuntu box and from my Bluray player.

In any case, if this is an Android 6.0 issue, and not an SPMC issue, feel free to close this out.

[Dime04]

Vpulim....I'm having the exact same issues as you are with the same setup. Shield TV running through the Samsung K950. Video stuttering and no audio when trying to play an Atmos based movie through SPMC. When I switch the audio track or disable the True HD option under the audio settings the movie plays fine as well as the audio.....just no Atmos sound. I can play a UHD movie using the Vudu app in the Shield TV and it plays back perfect with Atmos sound.....so I'm little perplexed as well.

[vpulim]

@Dime04 I'm glad I'm not the only one having issues with SPMC/Kodi and the K950 :)

The reason you don't have any problems with Atmos using Vudu is because they stream their movies using Dolby Digital Plus (Atmos works with either Dolby Digital Plus or TrueHD). For some reason, the K950 has no problems playing Dolby Digital Plus streams from the Shield TV. It only has issues with TrueHD. Most Atmos movies from blu-rays use TrueHD instead of Dolby Digital Plus. This is probably why you are able to hear Atmos from Vudu but not from your movies (ripped from blu-rays) using SPMC.

You can also test this in SPMC or Kodi v17 by playing the Dolby Atmos Demonstration Disc and switching between the TrueHD and Dolby Digital Plus tracks. Atmos works fine when playing the Dolby Digital Plus track but fails when playing the TrueHD track.

I'm trying to reach Samsung engineers to explain this issue but haven't been able to get past their Tier 1 customer support yet. I also posted on the Nvidia Shield forums and they were saying that the issue is related to Android 6.0 and that when Nvidia upgrades to Android 7.0, the issue might be fixed.

[vpulim]

By the way, this looks like a dupe of this issue: #346

[Dime04]

@vpulim Well I managed to come across a couple of files that played perfectly through SPMC and pushed out DOLBY ATMOS sound. They're official Dolby Atmos files to showcase the sound though they are formatted to m2ts....which I don't think make a difference. It's just another container to hold the files. So I went ahead and took the m2ts file and demuxed it to separate what was inside to see what the difference was compared to my BluRay ripped MKV files. The contents inside were an h.264, a thd+ac3, and an eac3 file. The thd+ac3 file was a Dolby True HD 7.1 file with embedded AC3 5.1. The eac3 file was E-AC3 Dolby Digital Plus 7.1 with an AC3 5.1 core........The contents in my MKV Blu Ray ripped files are a Dolby True HD 7.1 thd file and a AC3 5.1 file. Nothing embedded or no cores.

The funny thing is when I played the m2ts file through SPMC it was the E-AC3 audio track that pushed out the ATMOS sound....not the TRUE HD track. I also tried the m2ts file in the USB port of my Samsung 4k Blu Ray player using the same method and it played back perfectly as well using the E-AC3 audio track.

Don't know how much this helps but it's just some extra info that I thought you might find interesting. I hope I'm getting closer to figuring it out.

[vpulim]

Thanks for verifying. As I mentioned above, Vudu and the e-ac3 Dolby Atmos demo tracks you tested should play fine since they rely on Dolby Digital Plus as the transport. The problem is when you try to play TrueHD tracks. Unfortunately most blurays seem to only embed Atmos into their TrueHD tracks and don't include an e-ac3 (Dolby Digital Plus) track.

From my research in other forums, it looks like a bug in Android that is causing issues with TrueHD pass through to some hardware receivers like the K950. Hopefully a fix will come out in the next Android N release.

[Dime04]

@vpulim Yeah what you said before finally made sense to me now......just had to see the contents with my own eyes to fully understand it.......what's still puzzling me is if I play the mkv file with TrueHD through the USB port of my 4k Blu Ray it still doesn't pass the the audio. So my 4k Blu Ray player is suffering from the same problem so to speak. So do you think it's more a case of a problem with the K950 and MKV files?

[vpulim]

Thats interesting. I think what's going on is that the K950 is really picky when it comes to how the TrueHD streams are packed. When I hook up my Shield TV to an Onkyo NR626 receiver, the receiver is able to play the TrueHD stream just fine. So, in this case, the Shield TV is packing the TrueHD stream in such a way that only the Onkyo is able to play it, but not the K950.

And then, in your example, your Bluray player is also likely packing the TrueHD stream in a way that the K950 can't handle. I'm trying to get a hold of Samsung engineers to report this issue, and it would be helpful to give me the make/model of your Bluray player so they can have more examples of where TrueHD playback fails.

I don't think it has anything to do with the MKV container... as long the Blueray player can play other MKV files, it means it is able to pull the audio streams out of the MKV container just fine.

[Dime04]

I own the Samsung UBD-K8500 4K Blu Ray Player.

[vharshit1]

I would like to report I am having exact same issue with k950 + nvidia shield tv + trueHD.

[wesk05]

@vpulim : have you tried this with the native Android video player (Photos & Video) or MX Player. If it works fine on them, then it is not an Android or Shield issue.

[Dime04]

@wesk05 I've tried my True HD files on the Photos&Video app as well as MX Player and VLC......still no dice. Only getting Atmos sound when attached to an E-AC3 format from the Dolby Demo files.