Patent ID: 7881371

Claim:
A method for decoding video or image information, the method comprising: at a computing device that implements a decoder, receiving a set of quantized transform coefficients; with the computing device, de-quantizing the quantized transform coefficients into de-quantized transform coefficients, wherein the quantized transform coefficients are logically arranged in a block, and wherein for each of the quantized transform coefficients the de-quantizing includes: based on position of the quantized transform coefficient in the block, selecting a group from among plural groups of scaling factors, wherein a group index identifies the selected group; depending on a quantization parameter index, selecting a scaling factor within the selected group, wherein the quantization parameter index and the group index together indicate the selected scaling factor in a lookup operation; and scaling the quantized transform coefficient by the selected scaling factor; and with the computing device, applying an inverse transform process to the de-quantized transform coefficients to generate reconstructed information therefrom, the inverse transform process applying inverse transformation calculations having values such that each multiplication operation in the inverse transformation calculations can be performed by a shift operation, wherein the inverse transform process is orthogonal, the values of the inverse transformation calculations are based on values represented in an inverse transform matrix with plural columns having different norms, the inverse transform process is a two-dimensional inverse transform with row and column inverse transforms, the two-dimensional inverse transform having different norms, and wherein the de-quantizing uses the selection from among the plural groups of scaling factors to at least in part adjust for the different norms of the-two-dimensional inverse transform.