MKV Unprocessed Task Adds Audio Delay—Breaks Playback in VLC, Apple TV, and Plex

[John_Freiman]

@Goose

Hmm I don’t see any delay after the conversion with the files you had uploaded earlier anymore.

Did you test videos that have TRIM at the beginning of the video - to cut studio credits?

I have tried both with remux and skip remux, and both introduce audio delays that were not present before.

I’m in the process of uploading the most recent example to my folder named \2025-08-28\

[John_Freiman]

Even the videos that have just been renamed and subs muxed appear to have all carried over the delay properly – 20 ms on the source, 20 ms on the processed video.

4 second trim outcome.
first with no trim, second with 4 second trim

[Goose]

Yes I did see that. It’s how ffmpeg works when copying (no reencoding) streams. However I’m not seeing any issues with the playback, infact the playback is perfectly in sync when using VLC to play it back as it’s just storing the time sync information in the MKV container. Are you seeing an issue with playback in VLC or Apple TV or some other player?

[John_Freiman]

@Goose

Are you seeing an issue with playback in VLC or Apple TV or some other player?

Correct.
Apple TV clients can NOT play these videos back. Also, if the offset is 6-10+ seconds, VLC will not display the first couple/few seconds of video, while the audio starts pretty close to immedialy.

In the past, I have also had issues with my own Roku, via Plex Direct Stream/Play not be able to play them back as well, but since they were fixed/repaired by remuxing, I can’t say for sure this was the same issue, but since they played after turning off Direct Stream/Play I’m thinking it was possibly the same issue. I have not seen this issue on my Roku since they re-wrote the client app a couple of years ago.

[John_Freiman]

jfreiman:

Lastly (for now) - do you have a way of taking my mkv file (untouched) and play it back directly on you Apple TV via a USB stick or ethernet/cloud playback? I’m curious if this is a “Plex Thing” and “Apple TV Thing” or is it purely a “my thing!”

Funny you say that, I have that file I downloaded from your PMS sitting on the Desktop. When lying in bed last night I was thinking the same. Will test soon and report back.

Update that file was the correct one, so Download a fresh copy from you now.

@SE56

Just downloaded again and replaced my doctored version in PMS, now I will try using the ATV to watch “My life is Murder S05e03”. I will also change the setting back to Max like before.

@SE56

Just downloaded again and replaced my doctored version in PMS, now I will try using the ATV to watch “My life is Murder S05e03”. I will also change the setting back to Max like before.

@SE56

That file I just downloaded from your PMS will not play, it is not altered

@SE56

ATV Plex app Errors, what I could do is collect the Logs for you.

@jfreiman

Just to confirm I understand - You played it directly avoiding Plex?

@SE56

ok, the file plays with VLC no worries on my Mac. But with a huge delay unlike normal. VLC normally snaps open, this plays audio without video, then after a few seconds the video plays

Bad news the logging site is not functional since the last update

@SE56

That makes a lot of sense, the Apple TV has the ability to sync the Audio. In some cases it was too much by the look of it.

I also reviewed my Resillio app and see numerous instances over the years where Apple TV (with multiple users) played 0 minutes of episodes, while those same episodes appeared to have been played (in full) by other users or the same users on different devices.