Blu-ray Disc is a next generation optical media format. Each disc, the same size as a regular DVD, can produce a progressive video image resolution of up to 1920 x 1080 (known as 1080p) for exceptional visuals.
Blu-ray also offers a higher data transfer rate than television HD broadcasts for an improved picture presentation.
Currently Blu-ray can store 25GB of data on a single layer which means that dual layer discs can harbour a potential 50GB of HD content. Regular dual layer DVD is only able to present 9GB of SD content.