Hi all,
I’ve run into a consistent issue with MCEBuddy 2.6.7 using the “MKV Unprocessed” task. After processing, my MKV files show a negative audio delay of about -1.997s (confirmed via MediaInfo). This causes:
• VLC to play audio immediately while video lags behind with a black screen for ~2 seconds.
• Apple TV (via Infuse or Plex) to fail playback entirely unless the file is remuxed through MKVToolNix.
• Plex to struggle with Direct Play and/or Direct Stream—friend with Apple TV confirmed that these files won’t play cleanly on his setup until remuxed.
This delay is not present in:
• The original MKV file
• The file after HandBrake (NVENC x265) Only the MCEBuddy output introduces the delay.
Steps to Reproduce
Start with a clean MKV file
→ Plays fine in VLC, Apple TV, and Plex.
Run through HandBrake (NVENC x265)
→ Still plays fine, no delay.
Process with MCEBuddy 2.6.7 using “MKV Unprocessed”
→ Enable metadata download and file renaming (default settings as well as with Cut Start xx used).
Skip Copying and Skip remux are not checked/enabled
Open final MKV in MediaInfo
→ Observe Delay relative to video: -1 s 997 ms on the audio stream.
Play in VLC
→ Audio starts instantly, video lags with black screen.
Try Apple TV or Plex
→ Playback fails or buffers indefinitely unless remuxed with MKVToolNix.
Additional Notes
• Replacing mkvmerge.exe in the MCEBuddy folder with the latest version does not fix the issue.
• It’s possible MCEBuddy is invoking ffmpeg or using legacy flags that alter stream timing?
• Remuxing the final MKV with MKVToolNix (no audio delay correction) resolves the issue for all platforms.
Happy to share MediaInfo logs or sample files if helpful. Would love to know if others have seen this and whether there’s a way to prevent MCEBuddy from introducing the delay in the first place.
Thanks!
—John
Sorry, I forgot to attach Audio Delay and Black Screen in VLC.7z (121.8 KB)
I’m running into a similar issue with 2.6.7 and 2.6.6, but using MP4 High Quality. Halfway thru the movie, the audio gets out of sync with the video. This wasn’t happening in previous versions.
It’s actually not uncommon to see audio delays when converting files. They can happen for a variety of reasons.
MCEBuddy can detect these audio delays and compensate for them if required (by default it does not). Most of the time the delay information is stored in the converted video so the playback software should be able to correct for the delays at runtime. If that’s not happening with your player, you can ask MCEBuddy to auto correct for these delays by editing your profile.
and it should automatically correct for the audio delays while converting. Note this only works for profiles based on ffmpeg, handbrake and mencoder encoders, it does not work on profiles using the copy encoder.
Alternatively, if you’re seeing a fixed amount of deviation in all videos, you could also correct for it from the Conversion task → Expert settings → Audio delay
Well, I included the input file as well as the file that MCEBuddy creates in my upload. The input/original video has no delay and plays back fine on every device and app I have tried without any audio issues.
MediaIno shows no audio delay in the original file.
The Output file from MCEBuddy reports there is a delay, and causes the video to be either unplayable (Apple TV) or delayed video start on video players like VLC.
if I take the MCEBuddy video, re-mux it using mkvtoolnix, the video shows no audio delay and plays perfectly - no delays, failures, etc.
There is no consistent Audio Delay on the output video. They are different every time.
The MKV Unprocessed profile, shouldn’t be using Handbrake, This profile shouldn’t do anything but possibly trim the video without any conversion of the video or audio.
I am mearly using profiles to take my existing series episodes, integrate the subtitles, trim the start, if necessary, rename and move them.
So, I believe, that only ffmpeg and likely mkvmerge are being used. – If I am incorrect and mkvmerge is not being used, can I have MCEBuddy use mkvmerg to write the files with subtitles before moving them?
No, I have seen the deviations as small as a fraction of a second to as nearly 2 seconds - those are defiantly videos that can not be played by Apple TV.
Every video I use MCEBuddy to process goes into it with no reported audio delay. Every video that is output with MCEBuddy has a delay introduced/found – which doesn’t appear to have been there before.
I find it very unlikely that every video I have has had some sort of undetected/undetectable audio delay issue. I’m talking about tens of thousands of videos over the past 5 months. (I’m re-ripping everything in my TV library from the source media)
All of the videos merged by MCEBuddy take a second or two before the video appears in VLC Media Player on Windows - no matter how little or a lot the audio deviation is.
Correction, I just wanted to get a current sample of videos that I put through MCEBuddy in the past 24 hours and the first one I checked is well beyong 2 seconds
I just took the folder with one season I used MCEBuddy to add subtitles and organize yesterday – the series with the -7 s 600 ms deley, and I moved the files from my Plex TV folder, and put it back in cue in MCEBuddy with the audiedelay=auto and now the MCEBuddy output videos are now totally out of sync.
with Even the episode above with the -7.6ms is now -10.88ms – so it didn’t even use the 7.6 number and pushed the audio off by another ~3 seconds.
I just took some new episodes which were direct from bluray and ran it through MCEBuddy with the ffmpeg-audiodelay=auto change, and that video (as well as a couple others which showed no audio delay) through MCEBuddy and they all came out with delays ‘introduced’.
I suspect the delays are being introduced by ffmpeg during the remuxing intermediary step which is primarily needed to improve compatibility with other programs. Given your setup you may not need that intermediary step.
Try checking the option to Skip remuxing in the conversion task → expert settings page and see if that resolves your issue.
I literally have over 124,000 episodes with a majority of those episodes/videos having these (are they artificial?) audio delays - some which make them unplayable on Apple TV devices, and the remaining have delays in playing back the video on players such as VLC on other devices.
Currently, I am using MKV Unprocessed with the Metadata lookup set to prioritizing Season/Episode title and Overwriting Metedata Filenname ising TVDB for consistency and also to prevent shows that re-use episode titles from being incorrectly matched to the wrong season (I think MCEBuddy, always uses the earliest episodes S/E in the series…..
So, what would you suggest as the best/easiest method to remux these episodes without potentially screwing up the episode ordering?
Also, I haven’t paid too much attention to it lately, but I think the default Unprocessed does trim a bit from the beginning of each video to make sure there are no errors or dropped frames at the start of the video.
If I re-run MKV Unprocessed on these files again, it will trim each a “little bit more” from the beginning and that could ‘erase’ potentially important info from each video.
Since all the files are already named and have the appropriate metadata attached to each file, is there a better way to fix/repair all these videos – rather than using the MKV Unprocessed profile?
If no trim is done to the beginning of the videos, my external subtitles (with the .forced .sdh, etc could remain unchanged and and only the mkv file(s) would have to be remuxed.
That should not happen, that issue was fixed years ago. There should be NO trimming happening at all with the stock profiles.conf and stock mcebuddy.conf unless you’ve specifically configured the conversion task to trim in the expert settings or are using an old or custom profile.
I would recco starting a new topic regarding the metadata, I’m not clear what you’re trying to do.
We found the problem and it appears that the issue is a bug with ffmpeg, even if we tell ffmpeg to NOT cut/skip anything (-ss 0), if it encounters one it tries to sync the tracks and in the process loses the synchronization.
So if anywhere in the conversion process(remuxing, profiles etc) there’s a -ss 0 it will create this sync issue.
We will patch it up (right now most of our profiles also include -ss 0, so even if you’re skipping remuxing but using a stock profile it will still create the issue).
Try today’s 2.6.7 BETA build (keep remuxing on to test) and it should resolve the audio sync issues. No changes should be required from your end to your existing profiles or settings.
Oh, thank goodness! I was just logging in to let you know that I’m seeing the issue again - the other two files I tested must not have been representative of the problem.
I’m not sure if this is something with the beta, or with the beta, or if I skrewed something up while find/replace the remux settings, but the the srt subtitles are no longer being merged into the mkv – however, the external ones are being copied to the destination folder.
I just dropped a new zip file into the upload folder so you can take a look.
Contains: logs, and conf files
The Longmire episodes were ones I created back in Oct 2022 that have this issue as well.
The Forgive Me episodes are ones I just transcoded in Handbrake - verified, no audio delay.
ERROR> 2025-08-27T06:05:47 MCEBuddy.AppWrapper.MKVMerge → Application File Not Found or not accessible : C:\Program Files\MCEBuddy2x\MKVMerge\MKVMerge.exe
Thanks.
I reinstalled and the folder and exe are present.
Ok, I’ve resent the episodes from yesterday (~60) and those files appear to look good.
Taking some episodes (Longmire) that were processed through MCEBuddy in 2022 and running them through MCEBuddy again with the new build with Remux set default and Skip, still retains the prior files “delay relative to video”.
If I take that same file from 2022 and put it through MKVToolNix without any delay for the audio track, the output file shows no delay in MediaInfo and plays immediately in VLC with no delay in video starting.
Do you think that there is a way to “correct” and/or remove the delay using MCEBuddy?
I just checked and, honest to god, looking at a random sampling of all my series episodes going back to at least 2022 have delays – thankfully the episodes I have checked from 2014 and 2015 do not appear to have the delays (but those a) don’t have external subtitles and b) They were converted via MCEBuddy with Handbrake.
My concern and fear is that I started replacing countless series (30,000, 60,000? episodes) last Fall with new digital masters to replace my WMC recordings and others.
Let me know what options I have in front of me….. If that’s within your per view.
Hmm I don’t see any delay after the conversion with the files you had uploaded earlier anymore.
Can you upload the conversion log and the original file which is showing delays?
Steps to Reproduce
Additional Notes
