FFmpeg

The tool is quite good. Its main use is for converting from one format to another, but this is the netcat of digital A/V. Anything you could imagine doing to audio and video with a command line tool can be done with this tool.

The developers are of the mindset that there is no need for formal releases and that with all the formal testing in place and given SVN revision will work. For the most part this is true. Unfortunatly, there are a myraid of command line options, and at any given moment a given combination of them will fail.

For non-interactive video editing, ffmpeg is the best thing this world has ever seen. It can convert almost anything to anything, including audio. I was blown away by the number of advanced effects and features it offers, such as the new frame interpolation effect that can convert a video to higher FPS! It's really usable for scripting, for example if you need to make a video out of pictures, or vice versa. I've used it many times to fix dead pixels in my videos. I recommend to anyone who isn't afraid of the command line.