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This long command line (which should be all one line) will pick 9 images at defined frames and will write them as jpegs.

• The select filter selects the required frames.
• The setpts filter resets the presentation time stamps on the selected frames. With out it the output writing part of FFmpeg will repeat the last frame to fill the unselected timestamps.
• The yadif filter deinterlaces the frames, if required (yadif defaults to automatic detection mode).

ffmbc -i <input> -vf
      select='eq(n\,0)+eq(n\,25)+eq(n\,50)+eq(n\,75)+eq(n\,100)+eq(n\,125)+eq(n\,150)+eq(n\,175)+eq(n\,200)',
      setpts='N/(25*TB)',yadif -vcodec mjpeg -f image2 output%06d.jpg