Video not sync'd with audio

I been converting some videos into a format and size that allows playback in SL. I always test that the converted videos play properly in Quicktime on my local workstation before posting them on a server and playing via Parcel Media in SL. I've found that keeping size down is obviously important to reduce delay in video startup but the real isse has been with "talking head" videos where the video (person's mouth movements) is very noticibly out of sync (behind) the audio soundtrack, only when viewed in SL. Has anybody found a good way to avoid this problem?

I'm using this "Super (c)" software for video conversion/encoding which seems to work well:
http://www.erightsoft.com/SUPER.html

I've tried various encoding settings without noticing much difference. For example:
video format: MPEG-4
Video size: 384x288 pixels
frame rate: 25 fps
video bitrate: ~500 kbps
audio encoding: AAC (stereo)
sampling freq 44.1khz
audio bitrate: 64kbps
File size: 2.6MB

These prety much match the suggested settings posted on the Sl wiki:
http://wiki.secondlife.com/wiki/How_To_Show_Video_in_SL

Does anybody have any experience with getting good conversion out of videos or is this synchronization problem just an effect of the SL environment that can't be addressed?

Thanks for any ideas.

Your syncing can be due to either, you capture at a different rate than you render at, or you are rendering at a different rate to the capture. They may sound the same, but if you understand the principals of each, you will know what I mean.

If you use CrazyTalk for the lip syncing inserts, it defaults to 30fps when rendering.

There is also an issue in that the SL fps vary so much. Sometimes it is better to capture at slightly higher than the FPS you get in SL. If the fps is too high, you can also get frame drop. Using a professional editing programme, you can tween frames.