Audio Lag Increases As Video Plays

[brando56894]

I have this mpeg1 file that the audio lag increases in a non-linear fashion as the video plays.

I dont have the source file, is there anyway to fix this?

[brunersany]

the basic principle to fix this is to de-multiplex the mpeg 1 file and re-multiplex with TMPGEnc Plus 2.521 applying an audio offset. TMPGEnc Plus is a high quality MPEG1/2 encoder, and also has basic joining, splitting and multiplex, de-multiplex features.

[whatever-ever]

No, you can't just apply an audio offset since it goes out of sync progressively, not by a constant.
Only way to fix is to apply appropriate offsets x minute(s) after another.

[brando56894]

I tried it the first way and I thought I had fixed it since my test point(s) synced up until I tried more and noticed it was out of sync before and after that point.

So what youre saying is that the video will never truly be in sync unless I add audio delay every few seconds for about an hour? :scared:

[whatever-ever]

If it goes that fast out of sync, then yes.

[Dark Shikari]

That sounds more like the framerate is wrong.

[brando56894]

I vaguely remember seeing something about the framerate when I was researching this lastnight but the two programs Im using wont let me adjust the framerate to anything other than 29.97, 30, or 50.

Its originally 29.97 so I bumped it up to 30 and it seemed to help a very tiny amount but I cant be sure since my a/v judging isnt exactly perfect (margin of error of about a second or two).

Any suggestions on what program(s) to use? I was using dvdlab pro 2 for the demuxing and the audio delay, but couldnt use it to remux/compile it since it kept saying that the vertical length was wrong so I used TMPGenc to remux/compile it but the frame rate that is close to my current rate is limited to 30 fps

Edit: I booted back into linux (since I use it as my main OS and the video wouldnt play before in linux since it was a wmv) and installed avidemux which will allow me to set a custom frame rate by increments of a tenth. I increased the frame rate to 30.97 and realized that I was going the wrong way since the gap was increasing instead of decreasing. Im trying different rates now. On the original file the audio ended about 4.5 minutes after the video ended, can someone give me a frame rate suggestion?

edit 2: I decreased the framerate to 27.57 and its just about perfect the a/g gap is <1 second now, but its still off some

[zilog jones]

27.57 fps is a very unusual framerate, it's probably supposed to be 29.97 so I would correct the audio instead of the video. Is the audio even the same length as the video? If not, try and make them so they are.

[von_Runkel]

It seems like a frame rate issue. Try Besweet or some other tool that can stretch your audio. A recommendation is to measure the frames that differs and make the exact adjustments accordingly. 30->29.97, 23.976->24 or vice versa have been seen more than often.