So I have yet another problem with Kdenlive. I get my usual footage from my camera which comes in as AVCHD (.mts file) and audio recorded from a separate source (MP3) and layered them together in Kdenlive 0.9.8 on Linux Mint 17.1 and the audio keeps falling out of sync with the video. On top of that this happens when I render a section: http://youtu.be/X7iNlcFBnc8

I'm not expecting much in the way of help here. I know AVCHD support on linux is pretty terrible, but I thought I had better do something.

Not sure but I believe Mint 17.1 comes with a bad MLT/LibAV* combination.
A solution is then to download daily builds that come with latest MLT/FFMPEG.
But first you should try to transcode your MP3 to WAV in case it would be a VBR audio seeking problem.

I've just upgraded to Xubuntu 15.04 with Kdenlive 0.9.10 (all from the Ubuntu 15.04 repos). I have the same problem with syncing the audio/video of an m2t file (encoded by kdenlive) with an mp3 file.

It seems like it might be something to do with the MP3 because it doesn't seem to match up with audio thumbnails, although I encoded the MP3 myself through Audacity, I didn't use the VBR.

EDIT:
I've tried using Audacity to convert the MP3 into a WAV and it's solved all the problems. I think it's audacity or the MP3 codec there within that's the problem.