I have seen some basic info in general technique videos, but I was wondering if there's a really good video dedicated to river reading? It would be cool to see POV footage with some voice over of why this line not that line, what the person is looking for, starting easy and moving up to more complex features.

Yeah, its a cool idea, I admit. But there is no sudstitute for experience. A paddler is supposed to hang out at each classrating for awhile longer than today's newbies do- learn extensively to read the class III environment before moving immediately past class IV and straight into V like these kids all seem to do.

Technology is great but,
The best video to watch to get the gist of reading water (and kayak philosophy in general) would be a classic 'lil flick called:

STAR WARS A NEW HOPE

Particularly the scene where Luke is lining his shot up to destroy the Death Star. He's looking through that rickety gadget that is not entirely dissimilar to a gopro when Obi Wan says:
"Luke... Let go- trust your feelings. Use The Force

Orsomethinglikethatitsbeenawhile

You want to read water? Just go boat a ton, obviously. But you know what Yoda would say? He would tell you to go sit beside a rapid or drop somewhere. Clear you mind of all distractions. Breathe. SEE the river and its movement. Feel the pressure of it against the rock you are sitting on. Listen to the symphonic order of it all.

Don't forget to leave the camera out of the mix once in awhile and experience the purity of boating stripped free of the extra motives of showing others what you are out doing or what you think its all about. You can See more deeply when you are not preoccupied with extruding your experience through a digitized lens. See more deeply, focus deeply. Then the river reads like an open book.