It's a DVD, and the videos in it are all compressed, that is, slimmed down. The original hundreds of meters of high-definition movies have become tens of meters, and the number of stored movies has increased a lot, but the picture quality has been greatly reduced. Most of the videos are converted into MP4 format, which can be recognized by the players in the car. Because of the limited resolution of car TV, people sitting in the seat don't feel much about the picture quality, just like watching cable TV.