For this reason, I always download each video twice and compare the file sizes.
Sebastian001
You're doing too much work for yourself: basically you want to check the duration of the video track and the audio track, and the way that I catch others is (since I download subtitles into a separate file) is to check that the last timestamp in the subtitles file is not past the duration of the video track ;)
(in case you haven't figured out, my $job is in dependable and fault-tolerant computing ;) so all these sorts of (what we call) "reasonableness checks" are a second nature to me)