Hi
Using an input file with the following format (mplayer diagnostics)
VIDEO: [MJPG] 1280x720 24bpp 24.000 fps 19470.5 kbps (2376.8 kbyte/s)
AUDIO: 11025 Hz, 1 ch, s16le, 176.4 kbit/100.00% (ratio: 22050->22050)
I have rendered to 1024x576, H.264+MP3, which works well if I do not trim my clip. However, if I cut out boring parts from the beginning, the rendered output has a huge audio/video async.
It does not occur, if I first convert the original file to DVD format, and work on that in kdenlive. But this is clearly not the way to go... Why is this?
I am using kdenlive from ubuntu-9.10 (version 0.7.5, but I can give more details on the versions if I reboot into 9.10 - now running 7.10)

Can somebody explain, which codecs/containers cause this async? If there is a specific codec/container combination, which kdenlive likes (no a/v async in rendered output, no degradation in quality, etc etc etc), then I can simply convert all my input videos to this format.

What's the fps of your project ?

I had similar issues using 30 fps footage (coming from a Digicam) in a PAL project
with 25fps. After resampling the 30fps to 25fps externally (avidemux) sync was no problem
anymore.

There were some a/v sync fixes in MLT v0.4.6 for the Kdenlive v0.7.6 release.

Do this test to see if it might a problem in FFmpeg or MLT. Play the clip in a terminal window with 'ffplay' and then click around on the window to make it seek around (seeks relative along horizontal axis). Then, let it play and try to determine if it looks in sync.