I want to record a mjpeg stream via ffmpeg, but as the framerate of the mjpeg is very unreliable the result video is at first to fast and the speed changes.
The source i used to test is: http://c-cam.uchicago.edu/mjpg/video.mjpg
Try to adjust the bit-rate, and the tolerance setting (it's controlled by the -bt switch). it needs to be higher than the bitrate divided by the fps, as in:
tolerante > bitrate / fps