I'm using the following to build a preview filmstrip image by grabbing every Nth frame and tiling them into a grid:
ffmpeg -i "$file" -frames 1 -vf "select=not(mod(n\,$N)),tile=${COLS}x${ROWS}" -y strip.jpg
However the input video has black bars so I'd like to crop them out before grabbing those frames using something like:
-filter:v "crop=1440:1080"
Adding that has no effect on the tiled output image. I have also tried incorporating that filter into the -vf option to no effect. Is there any way to accomplish this without a second pass that renders the whole video (temporarily) cropped? Thanks!