A/V sync issues on TrueHD playback?

General Discussions
1

Synology DS412+
DSM 6.1-15047 Update 2
PMS Version 1.5.1.3520

This applies to direct stream, video copy, audio transcode from TrueHD to AC3. Source is a raw Blu-ray backup MKV, 1080p, 35748 kbps H.264 video, 7.1 TrueHD audio, PGS subtitles (not enabled) made with MakeMKV. Playback is on Roku 3 PlexPass native app.

After upgrading to 1.5.1, playing back this kind of content (anecdotally, tried two titles with similar characteristics) produces a video stream that seems to slow down and catch up to the audio. The audio playback is flawless, but the video just can’t seem to properly synchronize to it.

I’ve noticed a new process taking up a significant amount of CPU when playing back this kind of content. In Synology’s Resource Monitor it shows as “EasyAudioEncoder”, and in “top” it shows as “Plex EAE Service.” This is in addition to a high level of CPU usage on “Plex Media Server.” I can’t help but wonder if this is related to the recent switch of TrueHD decoders? I’m going to try downgrading later today when I can get the kids outside (raining in Houston), but in the meantime I wanted to see if anyone else was having this issue.

I attempted to re-analyze the library entry, thinking that maybe there was a new piece of metadata in the scanner to accompany the decoder change.

I checked the logs, but I’m only seeing DEBUG level messages and nothing alarming. I can post them if someone thinks it’d help.

Not seeing any issues with other “Plex Transcoder” sessions. I’m playing back direct stream, video transcode (MPEG2 -> H264), audio copy with no issues currently.

I have a high level of technical proficiency. If need be I can work with an engineer to diagnose further.

Anyone else seeing this issue?

2

Downgraded to 1.5.0.3501 and I no longer see the issue. The transcoder is using the “truehd” decoder now, not the “truehd_eae” decoder, and the EasyAudioEncoder process isn’t running.

3

Would you mind carving off a sample of that file so it can be forwarded to the transcoding team for further evaluation?

Also, please collect the Log files from the session, stopping as soon as you can detect the loss of sync. (settings - server - help - download logs). Attach this ZIP file here with your next reply. ^^

4

Server - Unraid 6.3.2 using Linuxserver.io docker for Plex version 1.5.1.3520
Player - Xbox one

Having same LipSync issue with the movie Sing which is Dolby True HD 7.1. So bad it is unwatchable. Since I am trying to fix this quick so the kids and I can watch it I am just going back to 1.5.0.3501-3b8374a5c using the version variable in the docker to see if that solves it. If not I will go back to latest Public release and try that. I will post back here after the movie or tomorrow to let you know how that goes. Unless it’s still not working.

5

Without log files, some more details as to the layering and resources available, with sample files, there is nothing actionable which can be done.

Respectfully, If you were a mechanic and I said “It’s so loud I can’t stand it.” , what would your reaction be?

Please help us help you so we can fix whatever is wrong for everyone?

6

I confirmed that rolling back a version fixed my issue too. We watched Sing with the kids just fine after that quick rollback. I love unraid with a plex docker from linuxserver.io!

7

Here’s a 45mb sample I created by dd’ing the front of the file. It’s not long, but I notice skipping in the video stream almost immediately (before the word UNIVERSAL even appears). Playing back the sample (as opposed to the whole file) was even worse, which was sort of strange. Logs are attached, too. Let me know if there’s anything else I can do to help. I have a theory that I’m working on that involves the fourth stream in the file, which is the cover image that MakeMKV attaches when you back up.

I’ll keep you posted. Thanks for responding.

8

I recently started seeing this error in the log. new files in the temp directory are being created with permissions 755 correctly.
I have not had any sync problems or loss of audio.
But yet still I was curious…

[Dolby, Dolby Digital, Dolby Digital Plus, Dolby TrueHD and the double D symbol are trademarks of Dolby Laboratories.
error renaming “/plextmp/EasyAudioEncoder/Convert to WAV (to 8ch or less)/a22ef9d45b04745f-com-plexapp-android-18369-1-1511.tmp” to “/plextmp/EasyAudioEncoder/Convert to WAV (to 8ch or less)/a22ef9d45b04745f-com-plexapp-android-18369-1-1511.wav”: system:2]

9

Another set of logs and a sample. You can see it with the Minions during the intro. Also I did notice that watching through the web there are no sync issues. I noticed a hesitation in video playback on the xbox one with the latest plex version as well that was not occuring on the verison I rolled back to. My unraid server is running an Intel Core i7-4770S CPU with 16 GB RAM with a pool of 2 SSD’s for the cache drive where I install the docker applications.

10

Thanks. I will forward this to the transcoder team.

11

@drcorso do you mind letting me know what sort of CPU your unRAID server has?

12

@“Matthew Hitchens” Does this issue happen with all movies that have TrueHD audio tracks?

13

@chrisallen said:
@“Matthew Hitchens” Does this issue happen with all movies that have TrueHD audio tracks?

I might have some time tomorrow night to upgrade again and test. So far my sample size is only two titles (Sing, which is technically Atmos, and The Secret Life of Pets) , but I have at least 30 I can test. I’ll try to compare several permutations of audio and video and get back to you.

14

@“Matthew Hitchens” and @drcorso do you mind providing samples that are around 2-5min in length. That way the sample is large enough to test playback accurately. the current 10-13 second samples are too short sorry.

15

@chrisallen said:
@“Matthew Hitchens” and @drcorso do you mind providing samples that are around 2-5min in length. That way the sample is large enough to test playback accurately. the current 10-13 second samples are too short sorry.

Sure. Is there a place we can upload larger attachments? The forum limit is 50mb.

16

@“Matthew Hitchens” I have send you a DropBox upload request.

17

@drcorso I have also sent you a DropBox upload request for you to submit a larger sample as well :slight_smile:

18

@chrisallen the CPU in my unraid server is an Intel Haswell i7-4770S, I assumed that may be important and indicated that earlier. I can try to find another movie with TrueHD and verify if that has the issue too if that helps. I did notice that this TrueHD track has Atmos on it as well so not sure if Atmos is what is giving it trouble or not.

Also I uploaded a larger sample using your drop box request.

19

@drcorso and @“matthew hitchens” Some fixes for transcoding have been included in PMS 1.5.2. Please upgrade to this version and check that your issues is now resolved. If it is not. Please provide new logs covering your playback attempts made using Plex Media Server version 1.5.2

Thanks!

20

@chrisallen said:
@drcorso and @“matthew hitchens” Some fixes for transcoding have been included in PMS 1.5.2. Please upgrade to this version and check that your issues is now resolved. If it is not. Please provide new logs covering your playback attempts made using Plex Media Server version 1.5.2

Thanks!

Sadly, this didn’t make any difference. Same playback errors with 1.5.2. I’m sending the larger sample as you requested, along with the logs from 1.5.2.