Patent ID: 8036471

Claim:
A method of operating an encoding apparatus to compress image data, the method comprising: accepting in the encoding apparatus quantized transform coefficients of one or more blocks of image data; for a first region of an ordered series of quantized transform coefficients of a block of image data, the first region possibly including the whole series, the series having a most likely-to-occur amplitude, and at least one other amplitude including a next-to-most likely-to-occur amplitude, the encoding apparatus jointly encoding joint position and amplitude events that each are defined by a cluster of consecutive coefficients having amplitude other than the most likely-to-occur amplitude, the jointly encoding forming one or more position and amplitude event codewords, each joint event defined by three parameters: the number of coefficients having the most likely-to-occur amplitude preceding the cluster, the number of coefficients having amplitude other than the most likely-to-occur amplitude in the cluster, and an indication of which trailing coefficients up to a pre-defined maximum number denoted M of trailing coefficients have amplitude other than the next-to-most likely-to-occur amplitude, with the encoding using a 3-dimensional joint encoding mapping such that on average, the more likely an event is to occur the shorter the codeword used to encode the event; the encoding apparatus encoding the amplitude of the trailing coefficients that have amplitude other than the next-to-most likely-to-occur amplitude, the encoding using a first amplitude code mapping and forming one or more first-kind amplitude codewords; and the encoding apparatus encoding the amplitude of any one or more remaining coefficients that have amplitude other than the most likely-to-occur amplitude in any clusters that have more than M coefficients, the remaining coefficient encoding using a second amplitude code mapping and forming one or more second-kind amplitude codewords for the one or more remaining coefficients.