The DVG-555K supports the most popular disc formats such as DVD, CDG, VCD and even the latest, MP4. That means you can load five MP4 CDG discs with up to 500 songs on each disc. The Play & Exchange feature lets you remove up to 4 discs while one is still playing and we've added a Locking mechanism to the 5-disc tray for trouble-free transport. With the popular vocal features VocoPro is famous for, like Digital Key Control and Professional Digital Echo, the DVG-555K will be the best sounding investment in your system. You can even hook it up to a Dolby Pro-Logic 5.1 system for the ultimate home entertainment.