Nvidia Shield AV Sync Issue with Dolby Atmos

[srolomc 2]

Hello,

I am having a very strange and specific issue - I am not sure if the issue is with Emby or not, but unfortunately I am not sure where to start debugging. My issue is this - I created a merged MKV file for Lord of the Rings the Fellowship of the Ring using MKVToolnix.  The resulting file is the two parts merged with Dolby vision and Dolby Atmos preserved.  When I play the video file without using Dolby Atmos sound, when it transitions from the first part to the second part, everything is fine. When I choose the TrueHD 7.1 Dolby atmos track in Emby, when it transitions from the first part to the second part of the movie, the sound becomes significantly out of sync with the video (by 1 or 2 seconds it looks like). I am using Direct Play for the video, so no transcoding is occurring.  I have attached a copy of the Emby server log, and here is my hardware/software setup:

TV: Sony Bravia A8H

Media Player: Nvidia Shield Pro 2019

Emby App Version: 1.8.71g (beta)

Emby Server Version: 4.5.4.0 (Linux)

Again, I am not really sure where to start debugging here - I do not have another media player available to test this with that I know can play Dolby vision MKV files (i.e. it is hard to say if, for example, MKVToolNix did not properly merge the Dolby Atmos tracks). I figured I'd post this here to see if anyone had any thoughts or ran into the same issue.  As always, thanks for the help!

embyserver.txt

[mastrmind11 717]

do you have a transcode log to accompany this?  try playing it on VLC and see if you get the same result, could just be a bad encode.

[srolomc 2]

I have attached my ffmpeg log. I also installed VLC on the Shield and tried playing it. It actually worked fine - when it transitioned to the next part of the movie, the audio was still in sync. I will note; however, that when playing through Emby, the video shows up as Dolby vision, while in VLC it only shows up as HDR10. Both players do play the Dolby Atmos track though, but I thought that was worth mentioning.

emby_ffmpeg_log.txt

[ebr 14937]

I have to believe this has something to do with that joining.  Were the two parts encoded exactly the same?

[jrwalte 17]

I know this doesn't solve the issue, but another way to work around it is save the 2 files separately instead of merging and let Emby automatically start the second file when the first ends. Since is it two files not merged, you shouldn't have the sync issue.

Add "-Part1" "-Part2" and so on for however many files you have, keeping them in the same folder, and Emby will automatically start the next one in sequence.

[srolomc 2]

@jrwalte - Thanks for the suggestion! I was actually considering doing this, I just wasn't sure if Emby would start the second part automatically. But hearing that it does, I think I can just go that route if I don't figure anything else out with the merged files soon.

@ebr - The two files were encoded the same way. It definitely could be something with how they were merged together in MKVToolNix. Do you happen to know of any other video player that can play Dolby Vision MKV files? It would be good to do a more apples to apples comparison with another player as a test.

[srolomc 2]

EDIT - I read over the naming conventions again - realized you can't have any other videos in that directory.

@jrwalte - So I tried multiple parts, but that did not seem to work unfortunately. The second part does not show up in Emby, nor does it automatically play the second part after the first one finishes. For reference, my directory structure looks as follows (I also have a copy of a 1080p version in that directory):
 

The Lord of the Rings The Fellowship of the Ring (2001) - 1080p.mkv

The Lord of the Rings The Fellowship of the Ring (2001)-Part2.mkv
The Lord of the Rings The Fellowship of the Ring (2001)-Part1.mkv

If it would be more appropriate to start a new topic on this, then I can do that since it is a little off topic for this post.

 

Edited February 10, 2021 by srolomc

[jrwalte 17]

It's either because you also have the 1080p file in the same folder or needing the space after the file name " -Part1"

It will show an additional parts section if it works.

 

Edited February 10, 2021 by jrwalte

[Luke 37125]

Have you compared your file naming to our naming guide on split video files?

https://support.emby.media/support/solutions/articles/44001159102-movie-naming

Please note that for the best possible experience, we still suggest joining the files.

[jrwalte 17]

Ok yeah it is because you have other files in the folder.

[srolomc 2]

Yup thanks guys, I read the documentation again a couple minutes after I tried it and realized there couldn't be any other files in that directory.  I still wasn't able to get the merged video to work, but the split video files will work just fine for now. Thanks for the help! I might try pursuing the merged files again in the future - I would still like to try it in another video player that supports both Dolby Vision and Atmos as another data point if I can find one. I'll post again if I am able to make any progress there.

Edited February 10, 2021 by srolomc

[raven-au 17]

On 2/10/2021 at 10:27 AM, srolomc said:

Yup thanks guys, I read the documentation again a couple minutes after I tried it and realized there couldn't be any other files in that directory.  I still wasn't able to get the merged video to work, but the split video files will work just fine for now. Thanks for the help! I might try pursuing the merged files again in the future - I would still like to try it in another video player that supports both Dolby Vision and Atmos as another data point if I can find one. I'll post again if I am able to make any progress there.

I can only report that the same problem occurs with my recent encode of DV The Lord of the Rings Trilogy extended edition. Oddly the second part of the trilogy didn't have this problem, only the last two parts. I also note that back tracking once resolves the problem for me.

The same thing happens in Plex so it may be the player, assuming both apps use the same player on Android TV.

 

[Deathsquirrel 741]

On 2/7/2021 at 11:28 AM, srolomc said:

Hello,

I am having a very strange and specific issue - I am not sure if the issue is with Emby or not, but unfortunately I am not sure where to start debugging. My issue is this - I created a merged MKV file for Lord of the Rings the Fellowship of the Ring using MKVToolnix.  The resulting file is the two parts merged with Dolby vision and Dolby Atmos preserved.  When I play the video file without using Dolby Atmos sound, when it transitions from the first part to the second part, everything is fine. When I choose the TrueHD 7.1 Dolby atmos track in Emby, when it transitions from the first part to the second part of the movie, the sound becomes significantly out of sync with the video (by 1 or 2 seconds it looks like). I am using Direct Play for the video, so no transcoding is occurring.  I have attached a copy of the Emby server log, and here is my hardware/software setup:

TV: Sony Bravia A8H

Media Player: Nvidia Shield Pro 2019

Emby App Version: 1.8.71g (beta)

Emby Server Version: 4.5.4.0 (Linux)

Again, I am not really sure where to start debugging here - I do not have another media player available to test this with that I know can play Dolby vision MKV files (i.e. it is hard to say if, for example, MKVToolNix did not properly merge the Dolby Atmos tracks). I figured I'd post this here to see if anyone had any thoughts or ran into the same issue.  As always, thanks for the help!

embyserver.txt 2.5 MB · 1 download

Just bought these and watched this weekend.  Exact same issue with that title.  When I popped back out to the menu ans played again the audio was in sync.  I'll rerip that movie the next time I plan to watch it.

[Carlo 4330]

Are you guys converting these files then joining?

How did you rip them?

Did you use MakeMKV?

[srolomc 2]

@Deathsquirrel - This is exact behavior I noticed as well - if I exited the player after it transitioned to the second part and went back in, it would then be in sync. But I could not watch the whole movie in one shot without it getting out of sync when it transitioned between parts.

@cayars - Yes, I used MakeMKV to rip the movies. I then used MKVToolNix to merge the two discs into one file. Note that if you do this, you must have version 51 or higher for MKVToolNix if you want to preserve the Dolby Vision header information. You should also make sure you have an up to date version of MakeMKV, as preserving Dolby Vision information only works after a certain version (I forget which version is the minimum required for MakeMKV though).