Blu-ray disc is an optical disc format that can store high-definition video and audio. It uses a blue-violet laser with a shorter wavelength than DVDs to read and write data in smaller pits, allowing for greater storage capacity. A single-layer Blu-ray disc can hold up to 25GB, over 5 times the capacity of a standard DVD. Blu-ray discs also support advanced features like recording live television, interactive menus, and online updates. The technology continues to be developed to increase capacity and performance.