A source image is encoded into a base layer and an enhancement layer. The base layer represents a standard definition portion of the source image and the enhancement layer represents a high-resolution portion of the source image. The base layer is stored on a first data storage track of a storage medium,...http://www.google.com.au/patents/US6633725?utm_source=gb-gplus-sharePatent US6633725 - Layered coding of image data using separate data storage tracks on a storage medium
