Audio desynchronized

[foux]

Hi.

I'm encoding avi (DIVX+MP3) to mp4 files (x264 with h264 mencoder and AAC sound) and for every movie, the sound is perfectly synched at the beginning of the rip, but near the end of it, there's a really annoying gap of about half or quarter of a second between sound and video. Any idea how to fix this?

[tomlee59]

This is a very common problem, without a simple fix for most cases, unfortunately. If the drift rate is relatively constant, then you can correct the error by running the audio stream through an audio processing tool, such as Audacity, to increase or decrease the duration as necessary. In Audacity, there's an option, called Change Tempo, which allows you to do precisely what's needed. Depending on circumstances, you can perform this operation on either the source's audio stream, or on the output audio stream, whichever is most convenient for you.

In your case, the total error is relatively small, so some combination of tempo change and muxing offset should suffice to produce a satisfactory result.