Image quality:
Superior resolution is a big part of what makes Blu-ray look great. In layman's terms, this means you'll see a more detailed image: more clearly defined strands of hair, wrinkles in clothing, etc. The technical difference is that Blu-ray's maximum resolution is 1,920x1,080 (1080p), while DVD is limited to 720x480 (480p). Beyond resolution, Blu-ray also uses better video-compression methods, resulting in more contrast and richer colors. If you like the way HD from your cable or satellite provider looks, Blu-ray looks even better. It's the highest-quality video format available today, and in some ways it surpasses the picture quality of your local movie theater, especially when shown on a good-performing HDTV or projector.
Audio quality:
Audio quality is also improved. New high-resolution soundtrack formats, such as Dolby TrueHD and DTS-HD Master Audio, are essentially identical to the studio master, so you'll be hearing things exactly as the director and audio engineers intended. For more information check out the Blu-ray soundtracks section.
Special features:
Blu-ray also has additional special features over DVD. The most basic innovation is the pop-up menu, which allows you to access the menu functions while the movie continues playing. Other innovations include picture-in-picture video commentary and the ability to download new content right from your Blu-ray player, although your player needs to have the right Blu-ray profile to access these features. In our opinion, the special features on Blu-ray have mostly been underwhelming and aren't a good reason to upgrade. For more information on special features, check out our detailed discussion of Blu-ray profiles.