Audio Sync Problems With MP4 Files

[EmeraldTwilight]

I've been having problems with mp4 files downloaded from Google Video.
They seem fine when they start playing, but as the minutes pass the Audio and Video grow more and more out of sync. The videos I've been downloading are around 93 minutes long.
I am using Mac OS X 10.4.11, On an iBook G4.
Please help!!!

[Baldrick]

What is your goal with the video? Just play on your computer or convert or? What do you play with now?

And I'm moving you to our mac section.

[albloom]

It's been known to happen. I've found QTSync to be easy and
effective. Get it here:

http://www.qtsync.com/

[tomlee59]

This can also happen if your CPU isn't quite up to the job. If the bitrate of the video is a bit on the high side, and if your CPU is fairly loaded, it may lose track of audio-video timing in its desperation to keep up.

There are some ways to test this: One is to slide the playback control bar to the middle or near the end, say, and start playing back there. If it is in sync initially, and then degrades, then an underpowered CPU starts to look like the problem. Another test is to use different software to play the clip (say, VLC and QT). If the sync errors are different, then that tends to point away from the file itself, and toward the Mac. If the sync errors are consistent, then it is indeed the file, and something like Mutator will help. So, too, would demuxing, altering the audio track, and remuxing.

Good luck!

[AeroQ]

Hello,

Audio shifting can be done with SimpleMovieX.
You fix the sync issue, then save the movie in MP4 or MOV format, without re-encoding.

http://simplemoviex.com/SimpleMovieX/

Regards, BJ