[FFmpeg-user] Extract image every x frames?

[Peter B.]

Hello,

I've found several examples of how to extract images from a video  
using ffmpeg. Unfortunately, my use case seems less popular, and I'm  
not sure how or if it is possible with ffmpeg:

I'd like to extract a frame exactly every 1500 frames - on material  
with different fps rates.

Any hints/tips/tricks welcome! :)

Thanks,
Pb