Patent ID: 6937652

Claim:
A method for compressing digital video data representing luminance values, first chrominance values and second chrominance values for a plurality of pixels, wherein for a respective pixel the method comprises: storing in memory a compressed representation of the luminance value for the respective pixel; generating a lookup key in response to the first chrominance value and the second chrominance value for the respective pixel; determining whether an entry in a data structure has a key that matches the lookup key, wherein the data structure comprises a plurality of entries each having a respective key, a respective identifier, and a respective pair of first and second chrominance values; when an entry in the data structure has a key that matches the lookup key, storing in memory the identifier of the entry in the data structure having the key that matches the lookup key; and when no entry in the data structure has a key that matches the lookup key, either: storing in memory the identifier of the entry in the data structure having a key that approximately matches the lookup key when the method is operating in an approximate mode of operation, or adding an entry to the data structure having a key that matches the lookup key, having a unique identifier, and having a pair of first and second chrominance values derived from the first chrominance value and the second chrominance value for the respective pixel, storing in memory the unique identifier of the entry added to the data structure, and setting the approximate mode of operation when no further entries are to be added to the data structure.