Adding a 3rd audio file causes audio sync/misalignment to the original movie

[andy-soft]

The fewer issues I have to read, the more new features I will have time to implement, so I ask that you please try these things first

• Try with the newest version from GitHub (also it might have already been fixed in latest nightly build)
• Read the documentation and FAQ, Known issues, Troubleshooting
• Search for your problem under Issues or Discussions
• This problem happens with all kinds of files that I try. For problem only with a particular file or type, use this other form instead

Operating System

Windows 10

Steps to reproduce

I took a Movie with English audio aac mp4a 2ch file
then I took another movie with Spanish track (same length)
then I use lossless-cut and export the aac mp4a file successfully
I test the audio positions with the audio English File (using a player: VLC) spotting specific segments at the beginning and at the end with the exported aac Spanish audio, they match perfectly!
Then I Import the aac file into the movie with the Engliss file, and merge them both (export all)

Expected behavior

The Video Images and Spanish audio should be perfectly aligned

Actual behavior

When playing with VLC, English (the original one) is aligned perfectly with the images
BUT when switching to Spanish Audio, there is more than 5 a 10 seconds delay!!
Simply Incredible!
(I repeated the sequence 2 times, same result)

Share log from developer tools

No response

[mifi]

is the delay constant throughout the whole video? or is the delay at the beginning of the video? how long is the video? did you try to extract all tracks as separate files, and then join them again? e.g. not (v+a) + a, but v + a + a

You might be able to fix the offset from the command line with the -itsoffset ffmpeg command, see #216

[andy-soft]

Hi mikael The delay is big, and spans across all the video, and I separated the files and joined them again with the same results.

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On Fri, Mar 13, 2026 at 10:49 AM Mikael Finstad ***@***.***> wrote: *mifi* left a comment (mifi/lossless-cut#2793) <#2793 (comment)> is the delay constant throughout the whole video? or is the delay at the beginning of the video? how long is the video? did you try to extract *all* tracks as separate files, and then join them again? e.g. not (v+a) + a, but v + a + a — Reply to this email directly, view it on GitHub <#2793 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ADII64MLFYHRFL6ILWMRNG34QQGYJAVCNFSM6AAAAACWHMXFV6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DANJVGE4TEMBQGI> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[mifi]

Hi! I see. It's a pity that i cannot reproduce the issue, but once I can, I will look into it.

[andy-soft]

I can send you the SRT, but the video is huge 3Gb (a downloaded movie). I could tell you where I've got it from, but I don't remember well; it was a torrent for sure

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On Fri, Mar 13, 2026 at 12:04 PM Mikael Finstad ***@***.***> wrote: *mifi* left a comment (mifi/lossless-cut#2793) <#2793 (comment)> Hi! I see. It's a pity that i cannot reproduce the issue, but once I can, I will look into it. — Reply to this email directly, view it on GitHub <#2793 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ADII64NV2YNXYR3CPE6T24L4QQPRFAVCNFSM6AAAAACWHMXFV6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DANJVHAZTMNZUGQ> . You are receiving this because you authored the thread.Message ID: ***@***.***>

[andy-soft]

AS long as I remember, it was the movie "my Gorilla", comedy, and the .srt I've got on opensubtitles was out of sync. I took a tool (subtitle edit) and resynced them manually, seeing the audio bursts and resyncing them visually, Then tested the whole (start & end) and saved the .srt Tested it using VLC, and it synced ok, When rejoining them into a single file using lossless cut, they went out of sync again! On Fri, Mar 13, 2026 at 1:06 PM Andres Hohendahl ***@***.***> wrote:

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I can send you the SRT, but the video is huge 3Gb (a downloaded movie). I could tell you where I've got it from, but I don't remember well; it was a torrent for sure On Fri, Mar 13, 2026 at 12:04 PM Mikael Finstad ***@***.***> wrote: > *mifi* left a comment (mifi/lossless-cut#2793) > <#2793 (comment)> > > Hi! I see. It's a pity that i cannot reproduce the issue, but once I can, > I will look into it. > > — > Reply to this email directly, view it on GitHub > <#2793 (comment)>, > or unsubscribe > <https://github.com/notifications/unsubscribe-auth/ADII64NV2YNXYR3CPE6T24L4QQPRFAVCNFSM6AAAAACWHMXFV6VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DANJVHAZTMNZUGQ> > . > You are receiving this because you authored the thread.Message ID: > ***@***.***> >