Software or method to detect sequences of non-black frames in a long video

Question

I have a large video file (about 6 hours long), it's a record from surveillance camera, the camera itself has no illumination features, though surveiled area has pretty good light which is triggered by motion detector.

So now I have a large video file that is mostly just a black screen, but it might contain some action.
Which software and or approach should I use to locate all action areas of the video (to watch 6 hour footage does not appeal to me).

I was thinking about video player that generates timeline of thumbnails or has built-in function to find non-black frames. I prefer solution to be free and opensource, but I have searched for a while and I am kind of desperate now, so anything (that will get the job done) will do.

Answer 1

You can use ffmpeg's blackdetect for that:

Let's say you are interested in blackscreen with a duration greater than 2 seconds (d=2):

ffmpeg -i "surveillance.mp4" -vf "blackdetect=d=2:pix_th=0.00" -an -f null -

output (example):

[blackdetect @ 0x7fac3b555380] black_start:40 black_end:53.44 black_duration:13.44