HTTP Stream (video) recording to a set of files

I just thinked that a usage of VLC's livehttp module on a certain project is way too resource hungry, just for recording video stream by 30-minute files. Thereby, what OSS software can be used to record an UDP video stream part-by-part? Excluding mencoder, since the recorded video should be gap-less.

Al开发者_如何学运维so, if writing own FFmpeg code, what is the best way to tell libavformat/libavcodec to switch file output after certain # of keyframes, using already cached last/next frames?