A few weeks ago I found a broken video at http://www.giantbomb.com/videos/late-nite-jar-sesh-08292012/2300-6509/ And commented: "The HD version is corrupted from 17:49 onwards. Don't know if I should email or something to someone to report or if a comment will be enough."
I forgot about it till now where I came across another and decided to come here secondly to report both videos, second being http://www.giantbomb.com/videos/thursday-night-throwdown-100412/2300-6648/ @ 25:18 in HD.
So I guess if this doesn't work (and I come back in a few weeks, maybe?) I'll email support. If reporting here does work and is okay, I'll post more corrupted videos as I continue through the backlog (slowly).
Edit: http://www.giantbomb.com/videos/thursday-night-throwdown-111512/2300-6807/ @ 59:05 in HD