Fixing audio mp4 sync.Anyone who owns an iPod video or PSP has probably coonverted video to watch on the bus. When converted from another source say avi or flash video (Which the clan approved FreeDownloadManager does very niceley) the audio can go out of whack & by the end of the piece it looks like a badly dubbed karate film.Here's how to fix it. I gleaned this stuff from the interwebs, but if you follow my guide instead of theirs you'll do it in half the time. You'll need Quicktime and the rather excelent VLC Player.1. Find the delay
- Open the video in In VLC Player
- Start playing the video & skip to where it starts to go out of sync
- Then press Ctrl+K or Ctrl+L to adjust the audio delay till it's back in sync. It'll show you the size of your adjustment in the top right of the window
- Repeat this at a few intervals, making the last adjustment close to the end of the video. The reason for this is that often the audio gets progressively more out of step the further you go through the video, so it's easier to do it a bit at time. When making your final adjustment, note the size of the audio delay you've introduced (measuered in milliseconds)
2. Fix it
- Open up the video in quicktime
- Drag the right hand selection marker (the black triangle) all the way to the right.
- Do Edit->Select All
- Now drag the right hand selection marker back for the same amount of time as your audio delay. e.g. 3000ms = 3 seconds
- Do Edit->Copy
- Do Edit->Add to selection & scale
- Select Show Movie Properties from the Window menu
- You'll see the video & audio tracks duplicated. Untick the first audio track and second video track so you're left with the original video track and new audio track
- Play the file to verify your work
- Go back to Window->Movie Properties and delete the unused video & audio tracks.
- Do file->Save As to save your video to a new file
3. Sip Champagne & nibble nachos.By the way if you're still using quicktime to play mov & mp4s, install VLC & use that instead. Or ffdshow & windows media player.