ffmpeg fast motion webcam recording

Question

I am trying to record every 12th frame from a webcam to a video file using ffmpeg to do fast motion (time delay) recording:

ffmpeg -f oss -i /dev/dsp -r 2 -f video4linux2 -s 640x480 -i /dev/video0 -r 24 out.mpg

No matter what I set the -r's too, it always seems to record at the same framerate.

Answer 1

mpg doesn't support low frame rates.

But to record at a certain FPS you can go:

ffmpeg -r 2 -f video4linux2 -s 640x480 -i /dev/video0 -r 2 out.avi

which records at 2FPS.

To speed that up 10x then you can pipe through yuvfps:

ffmpeg -i out.avi -f yuv4mpegpipe - | yuvfps -s 10:1 -r 10:1 | ffmpeg -f yuv4mpegpipe -i - -y faster.avi

The result is a video recorded at 2FPS that plays back at 20FPS (10x faster than original recording! yay)