In addition to some testing frameworks, I think mlt and kdenlive could benefit from Coverity analysis runs:
http://scan.coverity.com/ I've used Coverity at work and it is really good at finding memory and some other nasty API usage problems, pthreads for example. First results might be bad but there would be plenty of work for anyone interested in fixing problems here and there. I don't have experience with it from open source perspective, but many projects including ffmpeg seem to be registered there. -Mikko
