joining 2 avi w/nandub > audio out of sync

[chris_j11]

when i join 2 avi together (typically w/ac3) w/nandub
the 2nd movie tend to be out of slightly out of sync
is there a extra steps that i can take to prevent this
or is there another tool i can use that is more reliable

[guns1inger]

I do it manually with a mix of virtualdub and avisynth, and don't have any problems

[manono]

Hi-

Most likely the audio in part 1 ends before the video does. When you add part 2, the audio "slides" up against the end of the audio of part 1 and throws all the audio in part 2 off. You have to find out how much it's off.

Open the joined AVI in Media Player Classic and go to a place in part 2 where there's some close up dialog or a gun firing or something where you can judge the asynch. Pause it. Right-Click the screen and go Options->Audio Switcher->check Audio Time Shift. Estimate the delay (1000 ms=1 second) and if the sound plays before or after the lips move, or the door slams, or the gun fires. If you hear the gunshot after the gun fires, then you want to apply a negative delay. If the sound of the gun happens before the gun fires, then you apply a positive delay. Estimate that, OK it and resume playback. Adjust until you get it right. MPC makes real time adjustments. Once you have it, write down that delay (with positive or negative), uncheck that box and close MPC.

Open the part 2 AVI in Nandub, set preload and interleave for 96 ms (if AC3, not frames), and the delay for what you discovered in MPC. Set Video for Direct Stream Copy. Save it and give it a new name. Now the part 2 will be out of synch, but when joined to part 1, everything should be in synch.