Never located a good answer to this...

Is there a library that has an API, which will allow me to open a video file and append frames to the end? I've managed to spike my XFree86 installation to dump frames from a rendered window to hard drive, but then i end up with a thousand frames, which I must gather and assemble. I'd rather write them directly to a video file. Format is not important so long as 24-bit colour is supported.

Don't suggest GIMP scripts. That's not a dependency I want to carry.

Qvacks.