Here are some example command lines using video.flv with a native frame rate of 25 fps as input: ffmpeg -i video.flv -vframes 30 -vcodec png norm%06d.png yields the first 30 frames of the video in numbered png files. ffmpeg -i video.flv -r 8.333333 -vframes 30 -vcodec png samp%06d.png yields 30 frames of the video in numbered png files. This should output every 3rd frame of the video (1,4,7,10,13,...); however, comparing files shows that: samp000001.png = norm000001.png samp000002.png = norm000002.png samp000003.png = norm000004.png samp000004.png = norm000007.png ... I have also tested this on 59.94fps videos resampling at 19.98 fps (every 3rd frame) and 9.99fps (every 6th frame) and in all cases, I get the 2nd frame of the video in addition to the expected output. Thanks for your help, Jim Q.