All Blu-ray players can play commercial Blu-ray discs and standard DVDs. But you'll need an Ultra HD Blu-ray player to play 4K Ultra HD Blu-ray discs. Both types of Blu-ray players can play commercially released CDs and may play CDs burned with MP3 files.

What happens if you put a DVD in a Blu-Ray player?

Why Blu-ray Disc Players Can Play DVDs

When you place a DVD into a Blu-ray Disc player, it activates the red laser assembly so that the DVD can be read. When you place a CD into a Blu-ray Disc player, the same red laser assembly used for DVDs is refocused to read the CD.

Why won't my Blu-Ray player play regular DVDs?

There are several reasons a disc may not play in the Blu-ray player. A dirty or scratched disc is the most obvious cause, but an incorrect region code or configuration of your home theater system can be the reason as well.