Audio video synchronization: "scrubbing", what program?

[jimhoyle]

I have lots of video files, different formats (.mp4, .flv, .avi etc.), they all have varying audio/video synchronization problems. So I have to manually fix the audio for each video. I can do that already, but how I do it is so slow and difficult. I don't have a proper program to scrub the video and actually determine whether my audio is before or after and how much.

What is a program that could do that? In Adobe Premiere Pro it is in theory possible to push left/right arrows and hear ("scrub") the current audio block, which helps a lot. However, I have some problems with Premiere and it's very heavy for this simple purpose.

[Ghitulescu]

I don't have a proper program to scrub the video and actually determine whether my audio is before or after and how much.

Since the bits have a meaning for you only, but not for a PC, how do you think a software would be able to synch audio to video? Even synching audio to audio is difficult ....

[manono]

I can do that already, but how I do it is so slow and difficult.

As Ghitulescu said, there's no automatic way to do that. And you didn't say how you do it now that's 'so slow and difficult'. I use Media Player Classic Home Cinema. Play the video and use the +/- keys to adjust the audio synch on the fly. It says at the bottom the amount of the delay you've set. Once you get it right, use that figure to fix the video.

[yetanotherid]

I use manono's method. For fixing the files, VirtualDub for AVI, MKVToolnix for MKVs and MKVToolnix for MP4s. If for some reason I really, really have to keep an MP4 as an MP4, I use YAMB.
You're not converting the video to fix the audio sync are you?

Also..... Are you 100% sure it's the files and not your PC? For instance I was having major problems with MP4s at one stage yet I could re-mux them into MKVs and they'd play in sync. I'm not smart enough to know why, or for that matter why only some MP4s and not others, but a while back I upgraded to the latest version of the Combined Community Codec pack. Before installing, it asked me if it could disable some splitters it found on my PC and I said no. Not long after, I found another problem MP4. Thinking about that install I uninstalled the CCCP and re-installed it, this time letting it do whatever it wanted to do. When I tried the problem MP4 again, it played okay.

What media player are you using to play the files? Try VLC. Generally I don't use it but it's handy for testing as it uses only it's own internal splitters and codecs (as far as I know) it sometimes plays files differently to MPC via directshow, for example.