This step by step guide will show you how to fix out of sync audio and video in a video file.
There are two ways to fix out of sync audio and video – one is temporary and quick, the other is permanent and a bit more involved, although still quite easy.
Temporarily Fix Out of Sync Audio and Video
The quick solution is to use the amazing (and free) media player – VLC, and its easy to use built in audio delay/forward feature. If you aren’t using VLC yet, head over to their download page and give it an install. Note: this will work for all video formats, not just mkv/mp4/avi – they’re just common formats (and the 3 that I’ve found most often have sync issues).
- Open the video with the out of sync audio in VLC and then select Tools -> Track Synchronization (Mac users: select Window -> Track Synchronization)
- Locate the section titled Audio/Video – within that window there’s a ‘timer’ with “up and down arrows” to adjust the timing of the audio. This is where the magic happens.
- Use the “up arrow” if the audio is ahead of the video. That means if the people in the video are talking and you can hear them before their lips move, you’ll want to use the up arrow. That will ‘delay’ the audio, allowing the video to ‘catch up’.
So in reverse, if the audio is behind the video you’ll want to use the “down arrow”. That will speed the audio up.
In both instances, when you use the up and down arrows it will adjust your audio by 1/10th of a second per click. Let the video play while you’re making the adjustments – but note that it’ll take a second or three for the change to take place each time you adjust the sync timing.
Permanently Fix Out of Sync Audio and Video
To permanently fix out of sync audio and video, you’ll need to download an open source (free) video editor, Avidemux. It’s cross-platform which means it’s available for Windows, macOS and Linux.
Note: the screenshots used below are from a Mac, but the steps and screens are nearly identical if you’re using Windows or Linux and you should have no trouble at all following along.
- Once you’ve downloaded and installed Avidemux, open it.
- Select File -> Open…
- Navigate to the video file that’s out of sync, select it and then click Open
- After a few moments the video will open up in Avidemux. Use the “timeline slider” (see screenshot below) to move the video forward a bit.
- With the video paused, place a check in the box labelled Shift, which can be found in the Audio Output section.
- Use the “up arrow” in the Audio Output section to increase the number of milliseconds if the audio is ahead of the video. That means if the people in the video are talking and you can hear them before their lips move, you’ll want to use the up arrow. That will ‘delay’ the audio, allowing the video to ‘catch up’.
So in reverse, if the audio is behind the video you’ll want to use the “down arrow”. That will speed the audio up.
- Use the Play button to determine if the video is now in sync with the audio and keep adjusting with the up and down arrows until it is.
- Once you’re happy with the result, select File and then Save
- Give the video a new/different name so that you don’t overwrite the original, which you can delete later once you’re sure the new video is perfect. Leave the video type as mkv and then click the Save button.
- Give Avidemux a few moments to do its thing.
- Ta-da! All done. Click the OK button and then exit out of Avidemux. Open your newly created video file in your player of choice and make sure it’s all synced up.
Other Resources
How to Add Bookmarks to a Video
How to Extract Just the Audio from an MP4 File
Still accurate and greatly helpful in 2023. Thanks!
Many thanks, Ross. The Avidemux tutorial was just what I was looking for!
Why save as an MKV file and not mp4?
You just made my week (not my day, my week) wow…thank you so much!! I will buy you a coffee definately
To correct my previous email: the problems I reported with the compression are resolved by setting the Audio Output dropdown to MP4 Muxer (from the default mkv muxer). Excellent app, and it does wat it says it does (contrary to many others).
Avidemux is the only one that I could find that actually works and is workable because of the quick feedback when trying different delays. Excellent work, thanks.
Absolutely a flippin’ excellent tutorial and well, what can i say, brilliant brilliant . thank a zillion, how many times have i got out of syncer and just shifted it temporarily when i could have simply done this and ,,,well, thanks
Ok, I gave it a go and it did not work. The sound was 5 seconds behind the video. With VLC it was a simple adjustment and the sound and video was coordinated correctly for the rest of the video. With Avidemux it was an absolute pain to correct the difference but once I had at the beginning of the video it was out of sink just s few seconds later and so on. So it could not be fixed. My question is why was I able to do it for the whole video with one adjustment on VLC but it was unfixable on Avidemux? Somebody else had this issue and you said the sync of the whole video was different in different parts of the video. If that was the case how was VLC able to sync the whole video with one adjustment?
Oh man, does the Avidemux software work great. I am so excited! I bought a Logitech C922x Pro Stream Webcam, with the intent to create videos for my brand new YouTube channel. After I recorded a short test video, and opened it in Windows Media Player, I noticed a horrible lip sync problem. I was unable to find a fix on Logitech’s webpage. Fiddling with the webcam settings was of no help. I couldn’t find anything on YouTube to help me. After searching the Internet for help, I stumbled upon this page. I downloaded Avidemux, followed these simple directions, setting my audio output shift to +900, after trying different times. Now, my voice appears to be in perfect sync with my lips. I highly recommend this software. I would happily pay for this free software.
That avidemux fix was a life-saver, thanks.
Used it to successfully fix my sync issue but when converting the resulting MKV to MP4 it breaks the fix and it is out of sync again. Tried to choose MP4 as output and it doesn’t work – still puts it out of sync again!
Hi Andy –
No, Avidemux works for videos of any length. It’s likely that the video was out of sync by x seconds for the first half, and then y seconds for the second half. Avidemux would have fixed the x seconds, but then the second half was x minus y (or x plus y).
I just took a look at the advanced options (was hoping you’d be able to adjust audio differently at different points in the video) and unfortunately it looks like the solution is that you’ll have to use a video splitter, which isn’t the answer you want to hear I’m sure. So you’d need to split the video, use Avidemux to fix each half, then rejoin those two halves.
Hope this helps…
I re-synced a 90 minute video using Avidemux, following the instructions above. The problem I have now is that although it fixed the problem for about the first half of the video, it is out of sync again for the second half. Is there a maximum length of video that Avidemux can fix?
My friend (lol) has just started to have the audio /video not syncing in anything he downloads or has previously downloaded and had been working fine.. tried swapping VLC to Pot Player to fix problem but didnt change anything.. can anyone help or have any idea what can be done to resolve this issue?
It might not be a permanent solutions as others have mentioned, but at least I can watch my show without being completely annoyed!! Thank you ! :)
Thx!!!!
thanks, you realy help me a lot
In Windows, VLC has the ‘J’ and ‘K’ hotkeys predefined for quickly adjusting audio offset by increments of 50ms.