I have the following command, which converts a video and also generates a 10x9 tileset. Currently it gets the longer side and either generate a 90px wide or 45px tall tiles. My problem is that each tile has to be 90x45 large, so in essence what I need is a properly resized and centered tile inside a black bounding box. How can I achieve this?
The resulting tile
What I would like to achieve
Actual command line
ffmpeg -i K/vertical.mp4 .... vertical.out.mp4
ffmpeg -i K/vertical.mp4 -an -vsync vfr \
-vf select="isnan(prev_selected_t)+gte(t-prev_selected_t\,2)",scale="'if(gt(iw,ih),90,-1)':'if(gt(iw,ih),-1,45)'",tile="10x9" \
-qscale:v 3 './f/f%03d.jpg'