[FFmpeg-user] How can I use -vf blackframe to restrict encoding of images (skip night in timelapse images)?

[Andy Ritchie]

I am using ffmpeg to transcode timelapse images to video.

I can use -vf blackframe to get a list of black frames while encoding the
images to video, but I want to discard those images so that night goes by
quickly (in a blink).

Is there a way to conditionally process frames using filters or expressions
within ffmpeg so that I can use the -av blackframes filter to discard those
images?

This is my current commandline (it lists blackframes during encoding output)

ffmpeg -f image2 -i vids\frame_%%d.jpg -vf blackframe=100:84 -an -r 10 -s
svga -sameq vids\%1_%timestamp%.mp4

If not, I would love some pointers on how to proceed.

Thanks for your time,

-- 
Andy