Only commercially made disks, as I don't burn my own. The picture freezing appears to be the laser not moving on its track (I would hear the laser if it was moving around). Smacking the player gets it going again. Also, when starting the player frequently, the laser doesn't move and the DVD never starts. I get around this by manually moving the laser to a different position, which usually results in the laser moving by itself next time I start it up. There's no dirt in the player and I use an air can to keep it dust free.