I am sure it's most likely the compression, but I have ridden that trail dozens and dozens of times and I really can't tell what's going on in that video. From what I can see it was taken real early in the morning too so you're consistently going in and out of shaded areas in the fast sections up top.
Or maybe you're just going too fast trying to keep up with Danny boy :thumsup:.
The TW vids look way cool though, probably since there's no shadows. What kind of setup are you running for your helmet cam?