Software or method to detect sequences of non-black frames in a long video
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 &quot;surveillance.mp4&quot; -vf &quot;blackdetect=d=2:pix_th=0.00&quot; -an -f null -

output (example):
[blackdetect @ 0x7fac3b555380] black_start:40 black_end:53.44 black_duration:13.44