I have kind of a broad question about 4k content. I'm looking to buy a 4k tv I've done as much research as I could and came to the conclusion of getting the Sony XBR55x930e. All fine and dandy. Now my confusion is a 4k blu ray player. Many in the <$400 range I noticed say 4k upscaling. Now does that mean that they "just" take regular blu rays and upscale to 4k? Do they play actual uhd 4k blu ray discs or do I need the more expensive blu ray players to do those? A quick run down on 4k blu ray discs and perhaps recommendations on uhd blu ray players for the price would be appreciated.