I noticed that the video/audio timing is somewhat different between what kdenlive shows during editing and what is actually rendered. For example, I have a piece of music of 2 minutes, and it plays the entire movie in the background, and I add muted clips to it in kdenlive. Now I try to time certain events in those clips to the music, there's for example a "crash" in the music after about 30 seconds. However, when I place the clip so that the event exactly occures on the crash in kdenlive, after the export the event in the movie occurs approximately two seconds too early, so the music is two seconds behind. This happends with all the codecs that I can export to, and I timed the event in an external player and I concluded that the exported file has the correct timing, while within kdenlive the music plays too slow compared to the video.

I concluded that this is actually an error in the timing of the audio within kdenlife. The video seems to play at the correct time, and the audio/video of exports are fine as well.

Might this be a bug, or is it my configuration somehow?

$ kdenlive --version
Qt: 4.4.3
KDE: 4.1.00 (KDE 4.1.0)
Kdenlive: 0.7

Sounds like a bug to me, most likely in Inigo (the binary that plays back the video in Kdenlive).

Post it in Mantis and I'm sure someone like Mads or Dan with be able to offer some suggestions. If you installed it with the Builder Wizard I'd also recommend playing it back with Inigo and FFplay directly to see if it's the right timing / length there.

More (super easy) details on how at:

http://en.wikibooks.org/wiki/Kdenlive/Reporting_bugs

Right down the bottom under "Playback / Rendering Testing".