Some bluray discs use seamless branching to store multiple movie versions on a single disc. When ripping this disc to an MKV file it creates some audio sync issues on the Shield when the disc has Dolby TrueHD audio enabled (DTS-MA works fine). The same file works fine on my PC, I think the issue is bound to the ExoPlayer.
The video and audio go out of sync at specific chapter markers (at the branching cuts). When rewinding the movie in Plex the audio is temporarily fixed but goes out of sync at the next branchign cut.
An example for this is the Extended Cut of Black Hawk Down at the 14:35 min mark the audio cuts out for a splitsecond and then is out of sync. There is a Reddit post that might give more insight into this issue: Reddit - Dive into anything
I am running the latest client and server versions, but this issue has been there for a while so I don’t think this is relevant.
I’ve encountered this as well ripping discs with MakeMKV
I was able to remedy almost all of them or minimize the disruption to that one ‘blip’ without loss of sync by running it through MKVtoolnix
While it doesn’t fix all of them (I question the source material) it got all the ones that really matter. The few which didn’t fully repair have a minor ‘blip’ but don’t lose sync
It seems as if Exoplayer (used on the Shield app) doesn’t deal with this well.
This is well known and they keep trying different solutions.
MKVToolNix seamless branching remuxes usually generate a video that’s vfr with a peak of 23.976 fps.
This is because it doesn’t drop the overlapping audio frames like MakeMKV or tsMuxeR do, and changes the video to variable frame rate to keep it in sync.
If you transcode a MKVToolNix remux with Handbrake or ffmpeg as a cfr, duplicate frames are added at some or all of the branch points.
What exactly did you do in MKVToolNix? I just ran the MakeMKV rip through MKVToolNix but the issue is still there on Black Hawk Down. Is there something specific I need to do?
Yeah, you can remove the DV layer to just have the HDR10 video. I’m not sure if DV can be properly injected back into a vfr video though. You can try with dovi_tool if you want.
Are you able to share exactly your workstream? I have the same problem as OP for discs with seamless branching on my shield.
Any remediation on this would be great. I think there is some hot potato going on between plexm,inc and the devs on exoplayer on how to fix and neither parties are budging.
I’m not fully understanding here and suspect you didn’t see what was also posted elsewhere about MakeMKV.
Since I first ran across this problem, I’ve learned the source of the issue is in MakeMKV at those branch points with those codecs and how the output packets are sequenced (timed) as it impacts the different players (not just exoplayer).
I understand the frustration about it not being perfect but as I’ve stated, I got it down the bare minimal on those things I care about.
I am not understanding the assertion there’s unwillingness to make it perfect.
That’s coming off to me as somewhat unfair given just how many of the pieces are free software.
In response to my process.
MakeMKV - keeping ONLY those tracks I need
MKVToolNix (version 81.0) – which brought a lot of fixes for this problem. (82.0 contains more)
As it also happens when using DGDemux or eac3to its clearly NOT a MakeMKV issue, but an Exoplayer issue. With Kodi or VLC the issue is not there.
This does not work. Same issue persists. Release Notes of 81.0 or 82.0 also don’t include ANYTHING related to this problem. What are you talking about?
