How to Fix an Incorrect Audio/Video Sync Setting and Save it Permanently using ‘Avidemux’


Audio to video synchronization‘ is an  extremely important aspect of a multimedia file, because when playing, multimedia players rely on it for properly synchronizing the audio and the video tracks. If the synchronization value is incorrect, then the audio (or the video) is going to be played early or with a delay, compared to the other, which is commonly known as ‘lip-sync’ errors, and it jeopardizes all the excitement, obviously.

For instance, while watching a movie, if you have ever come across situations like gunshot firing sounds coming out before its video scene is displayed, then that is due to an improper audio to video sync. This is a pretty common issue in multimedia files and there are many reasons behind its existence, but for keeping the article clear and simple so that anyone can understand its context without having to go through boring technical details, I will not mention them.

In any case, the good news is, depending on the OS platform that you are using, there are powerful software multimedia players (VLC, KMPlayer, MPLayer etc) that give you the ability to manually adjust the sync setting, thus you can enjoy the multimedia files without such issues.

'Avidemux' running on Windows 8

The problem with that method however is that it only saves the sync setting temporarily, and it will be lost the next time you play it. However, thanks to a great open-source tool called ‘Avidemux’, you can save the audio/video sync setting permanently.

‘Avidemux’ supports multiple operating systems, therefore you don’t have to be a Windows user to do it either. Plus, it also supports lots of multimedia codecs and container formats (MP4, MKV, AVI etc), thus, you will be able to fix a lot of different file types too. So if you’re having lip-sync errors in one of your multimedia files, then you can try the below ‘Steps’ for a possible fix.

Step 1:

First of all, go to this page, download the package and install it (it has pre-built packages for Windows, Mac OS X and GNU/Linux).

Step 2:

Now open ‘Avidemux’ program and load the ‘troublesome’ multimedia file into it.

Step 3:

Before continuing, under the ‘Video Output‘ and ‘Audio Output‘ options, make sure it says ‘Copy’. Also make sure to enable the option called ‘Shift’ (disabled by default), as it is the option that lets you change the audio/video sync setting (shown below).

Enabling few primary options in 'Avidemux'

Any value that you enter here (‘Shift’) should be in milliseconds (1000 milliseconds = 1 second).

Step 4:

Now, if you know what the correct audio/video sync value is then you can skip this and go directly into the end of ‘Step 5‘. If not, click on the ‘Play’ button on ‘Avidemux’ window, so we can observe and see whether the audio comes before or after the video scenes.

If the audio comes ‘before’ …

Positive sync value - Avidemux

The rule of the thumb is that, if the audio is played before the video, then that means we have to ‘add time’ to it (thus delaying it), so the video track can ‘catch up’ with the audio track. This is done by entering a positive sync value (say 200 milliseconds) into the ‘Shift’ box.

If the audio comes ‘after’ …

Negative sync value - Avidemux

If it comes few seconds (or milliseconds) after the video scene is displayed, then it is already delayed, therefore, we have to ‘remove time’ from it, thus making it being played early.

One cannot give you the exact audio/video sync value that is needed as it is something that you will have to guess by observing the video playback. However, in my experience, the usual range is 200 milliseconds to 2000 milliseconds (2 seconds). But there can be occasions where it requires one to enter higher values.

Anyhow, unlike above, this time we have to add a negative value as the sync value, in order to make it load earlier (if you enter ‘-200′, then that means the audio will be loaded 200 milliseconds early).

Step 5:

Let’s assume that the file you loaded had an audio track that was being played with a delay. Then to make it play early, we have to enter a negative value. And unless the sync was so big that you could easily tell that the audio came few seconds after the video, I recommend that you start by entering a small negative (say a ‘-100′ milliseconds) value first.

If it fixes the lip-sync a little, then add another -100 (altogether ‘-200′ milliseconds). Then carry it on until you arrive at the optimal audio/video sync value.

However, before every time you apply a different sync setting, first make sure to ‘Pause’ the playback, then add the new value and resume playback. Otherwise ‘Avidemux’ will not apply that setting to the playback.

Proper way of entering audio-video sync values - Avidemux

Note: This is just an example (of course) and depending on your multimedia file, you will have to figure out whether to use a negative or a positive value, but the procedure is just the same.

Step 6:

Once you are satisfied with your new audio/video sync, now all you have to do is save the changes. But before doing so, just make sure that under the ‘Output Format’ option, you have selected the proper output format.

Choosing the proper container format - Avidemux

For example, if the source file was an AVI file, then make sure to select ‘AVI Muxer’. If it was FLV, then choose ‘FLV Muxer’ etc.

‘Avidemux’ doesn’t have like a huge list there, but it supports saving into AVI, FLV, MP4, MPEG-TS, MKV etc. If your input file has a different format than listed there, then you can choose ‘MKV Muxer’ as it supports storing a huge number of different audio and video codecs.

Note: Please be aware that, if you put audio/video that were previously stored in an AVI file into a MKV container, then sure MKV will store them without any issues. But most commercial hardware devices (iPad for example) will struggle to play it afterwards. This does not concern the computer users as most popular players support playing the awesome MKV format.

Update: Sometimes while trying to fix a MP4 file, though you might be able to successfully fix it and play it in ‘Avidemux’, the corrected sync value might simply be lost, after saving it into a new MP4. If this occurs, then I advice you to try selecting ‘MP4v2 Muxer‘ rather than using the ‘MP4 Muxer‘ (under ‘Output Format‘). I have been able to successfully save the corrected sync settings of certain MP4 files, by simply making that change alone!.

Step 7:

Once all is done, from its menu click on: ‘File’ -> ‘Save’ to save the changes permanently.

Depending on the length of the video, the time it takes will differ, but it should not take much longer (pretty much like copying that file over to somewhere else) since nothing gets re-encoded.

Saving a file - Avidemux

When it is finished saving, you can open that file using any media player, and if the sync value you entered was correct, then it should be playable without any sync issues. Well, that is it!.

Update: Some readers have complained that ‘Avidemux’ is not always working for them. So I wrote another method that uses another tool, which is known to work most of the time. However, that method only supports saving your input files (you can input almost anything into it AVI, MPEG, MP4, FLV …) into ‘MKV’, which as briefly mentioned above, is not playable on certain hardware based multimedia players. You can read about it from here.

97 thoughts on “How to Fix an Incorrect Audio/Video Sync Setting and Save it Permanently using ‘Avidemux’

  1. Billbo126

    I followed your guide to the letter, and the audio never synced, all the program does is make copies…I can do that through windows explorer…please help :(

    1. Gayan Post author

      Sorry to hear that mate. ‘Avidemux’ is not perfect & does not work well all the time. That said, what is the container format of your multimedia file ? (AVI, MP4 etc)

      Have you tried putting the changed file into ‘MKV’, under the ‘Output Format’ option ?

  2. ant

    i have a different method with avidemux
    before load files go to preferences /automation and tick all except bitstream.
    then load file ,leave all settings defaults ie copy.
    avidemux will run
    change format to mp4
    save file
    done

    1. John

      I have avidmux 2.6.4. It doesn’t have automation under preferences or anywhere else as far as I can tell. are you using a different version?

  3. Martin

    Hi Gayan, your recipe is missing two important bits:
    1. Typically, audio/video sync issues occur with DVB recordings. However, in that case the actual offset can vary throughout the recording whenever there is a bad packet in the MPEG transport stream. So you have to use a method that honors the timestamp embedded in the stream, like some players do (VLC does that pretty well, for instance). Avidemux unfortunately doesn’t. ProjectX does, but is very difficult to work with, and apparently fails on MPEG transport streams (at least those generated by my TV set).
    2. Even assuming the offset is constant throughout the file, you can’t find the right value by trying to play the video inside Avidemux, because Avidemux’s integrated player causes about 200..300ms audio lag itself. Even with a perfectly sync’d video file, playback inside Avidemux will yield delayed audio. Therefore my method is to select a short scene, transcode it with Avidemux, and play the result in VLC to see if it’s okay.

    1. Gayan Post author

      Thanks ‘Martin’, an interesting observation. I however, haven’t noticed audio delays while playing it through Avidemux’s internal player though.

  4. JJ

    I have a slightly different problem, the audio start out in synch, but gets ahead of the video the farther it plays. By the end, I have a black screen and audi only for about 8 second (45 minute concert vid) Any ideas?

    1. Gayan Post author

      Hi ‘JJ’,

      I’m not expert on this, but I too have seen these types of videos, where the sync gets worsened the further it plays. My understanding is however, it is because of corrupted A/V stream, and I’ve never been able to successfully fix them either. That’s the only info I have.

      P.S: There are however, ‘Audio Synchronizers’ utilities that are built to address these issues. There are both free and paid ones that you can try (just ‘Google’ the term ‘audio synchronizer software’ for that), good luck.

  5. Moses

    This is a great guide, however in AVIdemux 2.6.0 when i tried the delay with it set to “copy” i ended up with a file with no audio, so i updated to AVIdemux 2.6.4 and tried again, but this time i got no delay, file was out of sync same as original file. So i tried it with reencode of audio, to same audio format, and the delay worked then, probably with some slight degradation, but probably undetectable to most ears.

    1. Gayan Post author

      Hi,

      This could probably be an issue with ‘AVIdemux’, however, did you put (‘copy’) the audio & video into the same container format as the original one. Because sometimes, if you put the ‘fixed’ media file into a different container format (say that you put the ‘MP4′ content to ‘AVI’, this might not be even allowed if the ‘MP4′ contains codecs that are not supported by ‘AVI’, I just wanted to give an example), there could be such issues as well.

      As mentioned in the article, if the original input container of the file is not present in the ‘Output Format’ option, then you can use ‘Mkv Muxer’ as it supports virtually all the major audio/video codecs.

  6. Gary Anderson

    This is ridiculous how it does not work. You have it perfect but it just does not save the file you have just corrected. WHY WILL IT NOT SAVE THE CORRECTED FILE.

    WHY DO I JUST KEEP GETTING THE SAME FILE OVER AND OVER AGAIN WITH NO ADJUSTMENTS TO THE SOUND. THIS IS HARDLY ROCKET SCIENCE SO IT SHOULD NOT BE DIFFICULT TO FOLLOW THE ABOVE INSTRUCTIONS. THIS SOFTWARE IS NOT ALL THAT IT’S CRACKED UP TO BE

  7. kain1906

    Thanks a lot for this tutorial :) In my case when I’ve been trying to combine mp4 file with mp4 muxer I couldn’t save it. So I’ve changed it to mkv muxer and it helped :)

  8. FreshAir

    The suggestion to re-encode just the audio, fixed the trouble I was having. I figured out I needed 18 seconds of audio shift which is 18,000 milliseconds (the value you enter in the avidemux is milliseconds, in this case 18000), which is a lot.

    I had a mp4 video in a avi container. I’m using the Mac version 2.6.4 (r8694).

    My audio was ahead of the video by 18 seconds, which is 18000 ms (milliseconds, 1000 of which equal a second), which is the value you have to put in the shifting value box. You also have to check the box by shift window under “Audio Output” on the left hand menu. if it had been behind by the same amount the value in the shift box would be -18000 instead.

    Changing the shift box in the left hand menu automatically changes the same choice if you use the menus at the top of the screen. They are the same controller and should both be checked when in use and have the same value. I’d use the one on the left hand menu, since it’s right there.

    My video had ads that had been inserted after the 18 second delay had been introduced, so I had to chop those out before shifting the 18 seconds. After the ads were chopped out, I did the 18 second shift.

    The shifting showed up in avidemux after you stop the player and restart it in avidemux. The synch was perfect in avidemux.

    However, when I used copy for the video and audio, with of course the shift box checked and with the 18000 value, the resulting video copy did not reflect the shift I had done and the 18 second delay was in the new copy.

    I took the suggestion from the above comments and made a new copy. On the new copy I kept the video choice as copy but on the audio I changed copy to MP3 (Lame). Then on the menu I chose save, named it and avidemux made a new copy. Of course it took maybe a couple of minutes instead of 20 seconds to make the copy because the audio was being re-encoded.

    The result was a new Video with audio that matched the video. I don’t know enough to know if MP3 Lame was the best choice regarding preserving quality, but it did work and kept the file size similar.

    I’ve just starting editing so I’ve probably shared more details than some need, but I would have loved to have read this post several hours ago, before I had to figure out what value was supposed to be in the shift box and should it be positive or negative. Hoping I can save someone else the effort.

  9. Timothy s

    Using a Mac OS X . . ..

    I ripped a number of DVDs using MacX Ripper Pro and out of 100+ movies ripped, only three would not rip with ordinary settings. For those three it was necessary to use the “safe mode” option, but it left the audio out of sync.

    Your explanation on how to sync the audio is excellent. I also had problems saving the synced-up file, but found the following settings to work:

    Video Output – MPEG4 (x264)
    Audio Output -Copy
    Output Format – MP4 Mixer

    The file takes a long time to convert – 1:1 movie time.

  10. Timothy s

    Update after checking my results:

    Although I could save the corrected file, final rendering revealed the situation described in comments above. The file is properly synced at the beginning of the film, but gradually falls out of sync where by the end it’s as much as 3/4 sec. out.

  11. Jean-Luc Glorieux

    I was able to properly synchronize the audio with the video using your instruction, but then I was unable to save the corrected file. When you click “file”, then “save”, there doesn’t seem to be anything happening nor any is there any indication of the saving process to let you know when it is complete. Where is the “saved” file stored? When I try to play the original file which I loaded, it is not changed.

    1. Gayan Post author

      It should be saved in the location that you set after clicking on the ‘Save’ button (when you click it, it opens up a ‘file-save’ message box, here give a name to the file and a location).

      Please remember that, as I’ve said many times above and in the article, you should carefully select the ‘Output Format’, otherwise you’ll run into playback issues later. I do know that ‘Avidemux’ is not perfect and has its issues. For instance, I corrected the sync of a MP4 file and saved it in the MP4 format and it worked perfectly well. However, I also decided to save the same file into the ‘MKV’ format/container (within the same ‘Avidemux’ session), and the file was saved into ‘MKV, but without the corrected sync!.

      Weird enough, I clicked on the ‘Play’ button in ‘Avidemux’, and saw that even after adding the correct sync setting, the playback was still going on with the original out-of-sync setting (though on the earlier occasion, when I saved it into MP4, it played with the correct sync).

      So I manually changed the value to a different one, and let it play, and then re-changed it to the correct sync and let it play again, and this time it was playing with the correct setting. Then I saved it into ‘MKV’ again, and this occasion, it saved it with the correct sync setting.

      What I’m trying to say is that, most users who complain it not being able to fix their issues (though there certainly are occasions where ‘Avidemux’ doesn’t work), use a bit of common sense, and double check before you save things, because this usually fixes a lot of issues. Good luck.

  12. Jean-Luc Glorieux

    When I click “file” then “save” at the end of the process, no “file-save” message box appears as you mention above. Why is that?
    Also, I made sure to select the output format as MP4 (the same format as the original file) prior to saving.

    1. Gayan Post author

      I’m sorry Jean, I don’t know what it doesn’t appear. Just make sure that you’re using the latest stable version of Avidemux, and especially if you’re using Windows 64-bit, then try the 32-bit version of Avidemux rather than the 64-bit. Also, try changing the output format into MKV to see if that helps. That’s the best advice I can give you.

  13. Jean-Luc Glorieux

    Thanks for the prompt advice.
    Unfortunately, I tried both the 64- and 32-bit version Avidmux and still no save message box appears. I also tried to change to output format to MKV as you suggested, but also without success.
    I guess I’ll have to give up and find some other audio-video sync software.
    Thanks anyway

  14. Jean-Luc Glorieux

    It’s me again. I think I finally figured out how to do it. Apparently, you can only save the file in the “pause” mode, or at least when you click “pause” and then “save”, the “save” message box does appear and lets you name and direct the file to be saved as you stated. However, f you click “save” when the file is still playing, nothing happens.
    Thanks again.

  15. Jean-Luc Glorieux

    I apologize for being such a pest but I am again having a problem with the “save” function. Suddenly after modifying and saving successfully about a dozen files, I still am able to properly sync audio and video but I am then unable to save the modified file. The “save” function seems to work normally, but then the saved file is not the modified one but the original one. Any suggestions? Thanks.

    1. Gayan Post author

      Hi Jean,

      I’m not sure if this helps but you can try the following.

      1. Once you’ve figured out the correct sync setting/value, take a note of it (memorize it or save it into a text file for later use) and close all running instances of ‘Avidemux’).

      2. Then re-open ‘Avidemux’ and load the multimedia file and re-enter the sync setting/value directly into the ‘Shift’ message box (without using the playback toolbar).

      3. After that try saving the file (again, make sure to select the proper ‘muxer’) to see if it fixes it.

      1. Jean-Luc Glorieux

        Dear Gayan:
        Thank you very much for your quick feedback and suggestions. I did exactly as you suggested above but, unfortunately, this did not fix the problem and I am still unable to save the corrected file. Instead, the original uncorrected file is saved every time. This is very frustrating because, until yesterday, I had been able to successfully lip sync a number of my anime download files (all in MP4 format) but, now, I cannot continue this, even though I am not aware of doing anything different. Is there a prescribed file saving procedure (file name and/or location) which I am somehow failing to implement? I don’t understand. I even tried and re-installed the Avidemux software, but this did not correct the problem either. Any further suggestions you might have would be very welcome.

  16. Jean-Luc Glorieux

    Dear Gayan:
    Well, I mulled over some more this sudden inability to save the corrected file and I eventually decided to try one of the suggestions posted above (by Fresh Air on September 5, 2013) and set the Audio Output to “MP3(lame)” instead of “Copy”.
    I am glad to report that this also did the trick for me. It took considerably longer to save the file (probably because of the conversion which only proceeded at around 350 fps), but I ended up with a properly synced saved file. Hourrah!
    I still don’t understand what happened and why I started needing this procedural change all of a sudden, but any way that works is good enough for me.

    1. Gayan Post author

      Yes, when you choose anything other than ‘Copy’, it re-encodes the track and thus it takes more time. I’m currently writing about using ‘MKVToolNix’ for fixing these issues, though this tool only gives you a MKV output which is not that widely supported by hardware based players.

  17. Amol

    Hi..i could do all the steps properly but just as i save and play the file in vlc..d audio itself has disappeared”!!total mute…pls tell me solution for this

    1. Gayan Post author

      Hi Amol,

      To what container did you put the file into ? When VLC is playing the file, press ‘Ctrl + J’ key combination. This will show you the audio & video tacks inside the multimedia file. Take a look to see if it lists the audio track. If it does, then try playing the file with another application.

      If all fail, then you can follow these steps for correcting the issues and this method, unlike the one described in this article, most of the time fixes lip-sync issues, though its only drawback is that it forces you to put the corrected multimedia file into the MKV container, which however shouldn’t be a problem as long as you’re planing to play it on a computer (as some hardware based multimedia players don’t support MKV).

    1. Gayan Post author

      Hi Amol,

      I’m not sure what the issue is. However, try the suggested article of my above answer and that method should work without any issues since the file that you’re having issues is also a MKV file.

  18. Tim Jong-Il

    This is only if the audio isn’t in time with the video. Do you know of a way to fix the audio is it’s slightly slower than the video? As in, at the start of the movie it’s perfectly in sync, but by the 2 hour mark, it’s out by nearly half a second.

    1. Gayan Post author

      Hi Tim,

      This usually happens when the audio playback rate (based on the ‘audio time codec’ setting) is imperfectly matched with the video FPS. So as you mentioned, although the track may play ‘perfectly’ in the beginning, as it progresses, the audio gets ahead or behind the video, thus leading to a bad lip-sync. For instance, if the video fps is 30 but the audio playback speed is set around to match a video that plays at 29.97 fps, then it is going to create a small lip-sync issue as the track progresses.

      I haven’t tried to fix this using ‘Avidemux’ (I don’t think it supports it), but if you’re familiar with ‘MKVTooNix’ (I did mention it here), and if you can calculate (within a certain degree of accuracy) how fast/slow the audio has to be played so that it matches with the video fps, then there is an option in ‘MKVToolNix’ called ‘Stretch by’ that let you control the audio playback speed, and it might be able to fix it.


      A quick recap …

      Figure out the by how much the audio should be delayed or played ahead, then once installed, add your multimedia file into ‘MKVToolNix’ window and select the audio track and then simply enter the value into the ‘Stretch by’ box and save your changes. If you do this correctly, it should fix the issue.

      You can research this more by using the below articles if you like …

      http://www.animepassion.net/topic/1426-guide-for-time-stretching-audiotracks-in-mkvwhole-trackpartial/

      http://documentation.apple.com/en/cinematools/usermanual/index.html#chapter=2%26section=6

      Good luck.

  19. GBear

    Very good writing, thank you for taking the time to be clear. Most people don’t.

    I have a different problem, my mp4 videos play fine with various computer players, but then have audio sync problem when played with my Western Digital player connected to my TV. I find the problems are mostly with MP4, and not AVI. If I fast forward, they can get out of sync, and if I rewind a bit, frequently that clears up the problem.

    So it doesn’t seem like it is a problem in the file, but in the way the Western Digital device is playing the file. What might be going on here, and what should I do to try and fix it?

    1. Gayan Post author

      Hi GBear,

      First of all, you’re welcome. About the issue that you’re having: Well, since your MP4 files play just fine on other media players, it’s probably due to a bug in the software included in ‘Western Digital Player’. So other than saying ‘you should contact WD’, I have no other answer. Sorry about that.

  20. Bill

    I have a similar problem, except that I have some videos that have very low volume. The video, in the format its in is sync’d perfectly. When I use AVS Video editor to increase the volume the output video comes out of sync by several hundred ms with the audio leading the video. Does avidemux provide for an increase of the volume in its output? That’s the only problem I have is trying to get the volume high enough to play properly on my TV.

    1. Gayan Post author

      Hi Bill,

      No, unless you’re planning on re-encoding the audio track, ‘Avidemux’ does not let changing the volume level when used just for muxing, as far as I know.

  21. noblsht

    Thanks, I’ve been going around in circles for days trying many different methods to get the audio to sync with the video, I finally got it with your help and advice, one thing I would like to mention, Is when I first started loading videos I did not have any audio. In the application, If people have this issue what they need to go to is the audio settings and click core audio and then the audio portion will be audible in the software program thanks again

  22. CRISTY

    I have a different issue file syncs and saves however after saving cannot view it?
    have tried 2 different formats of the same video am I doing something wrong?

  23. Pejo

    Thanks for clear description and for saving my time with this very fast method of solving audio delay in video file.

  24. Todd

    I used avidemux and the sync worked great while still in the program. My problem I pulled in a mp4 and saved as an mp4 but it will not save as a useable file. Usually a mp4 file looks like a little film clip in my files. This looks like a piece of paper with the end folded over and list it as just (file). The same thing happens when I pull in an AVI file and save as an AVI file. Any suggestions.

    1. Gayan Post author

      I used the latest version of Avidemux on Windows 8.1 and everything worked for me.

      It seems to me in your computer however, that the output file’s extension goes missing while saving, so (again, assuming that it is the cause) you try manually add the extension (mp4 or avi …) while saving the file by entering the extension at the end of its name field, followed by a full stop.

      For example:

      myfilename.mp4

      Or

      myfilename.avi

      Totally unrelated …

      If the corrected sync setting does not get saved when saving as mp4 (happened to me) then try saving it into ‘MP4v2 Muxer’ under ‘Output Format’.

      1. Todd

        That worked. Thank you. This is so cool. I have deleted so many otherwise great bootleg concert vids because of the out of sync. Now I can fix them. I love it. I appreciate your time to help.

  25. John

    It works good until I save it and then it reverts back to non-sync.
    What am I doing wrong?
    Do I have to let the video play full length or can I stop it when I have the correct sync and save it.
    I have tried it both ways and it does not work. Still out of sync.
    Also unless I save it as the original name, it will not save at all.
    Non of the formats will work except for the “dummy”.

  26. Don Estes

    I went to download the software, and got this report from Norton:

    Norton Rating
    Norton Safe Web has analyzed open-any-file.com for safety and security problems. Below is a sample of the threats that were found.
    Summary

    Computer Threats: 1
    Identity Threats: 0
    Annoyance factors: 0

    Total threats on this site: 1
    The Norton rating is a result of Symantec’s automated analysis system.

    Needless to say, this is a little intimidating. Do you have another download site?

    1. Gayan Post author

      Hi Don…

      What I’ve linked is the official web-site of ‘Avidemux’ and it’s pretty trustworthy, I don’t know why Norton was complaining though…

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