Even with the fine track pitch and fine pits, which give a tremendous boost to storage capacity, an entire movie can't be stored on one side of a 12cm disc without powerful image-compression technology.

Use of compression technology is already widespread in the audio field where MiniDiscs, for example, rely on it, and it is making inroads in PC applications. But, compared with audio, image information is vastly more data-intensive. Global standards for image-compression technology are promoted by the Moving Picture Experts Group. Building on the success of the MPEG1 standard, the more sophisticated MPEG2 standard has been introduced. The DVD is MPEG2-compliant.

MPEG2 employs the variable bit rate method whereby the data rate varies according to the information content of the image. To achieve consistently superior picture quality, the data rate is reduced for graph with low information content and increased for graph with higher content.