Patent ID: 7813574
Filing Date: 2010-10-12
Classification: G06F,H04N

Abstract:
1. A decoding process comprising: computer implemented steps performed by a processor of a computer system to implement the following steps: receiving a block of coefficients relating to a block of video information to be displayed which has been transformed and quantized for compression of the video information; scaling the block of coefficients using a scaling factor determined for each coefficient in the block of coefficients by computing an index for one or more coefficients and indexing a look-up table (LUT) using the index for at least one coefficient; and converting the block of scaled coefficients to a block of output values by transforming each row of the block of scaled coefficients using a one-dimensional inverse transform to create a block of transformed coefficients and then, after transforming all rows of the block of scaled coefficients, transforming each column of the block of transformed coefficients individually using the one-dimensional inverse transform to create the block of output values in order to reconstruct a signal of the block of video information for display of the video signal, the one-dimensional inverse transform being implemented by the following sets of operations: a[0]=in[0]+in[4]; a[4]=in[0]−in[4]; a[2]=(in[2]>>1)−in[6]; a[6]=in[2]+(in[6]>>1); b[0]=a[0]+a[6]; b[2]=a[4]+a[2]; b[4]=a[4]−a[2]; b[6]=a[0]−a[6]; a[1]=−in[3]+in[5]−in[7]−(in[7]>>1); a[3]=in[1]+in[7]−in[3]−(in[3]>>1); a[5]=−in[1]+in[7]+in[5]+(in[5]>>1); a[7]=in[3]+in[5]+in[1]+(in[1]>>1); b[1]=a[1]+(a[7]>>2); b[7]=−(a[1]>>2)+a[7]; b[3]=a[3]+(a[5]>>2); b[5]=(a[3]>>2)−a[5]; out[0]=b[0]+b[7]; out[1]=b[2]+b[5]; out[2]=b[4]+b[3]; out[3]=b[6]+b[1]; out[4]=b[6]−b[1]; out[5]=b[4]−b[3]; out[6]=b[2]−b[5]; out[7]=b[0]−b[7], wherein the in[x] represent coefficients in the input vector retrieved from an input block and the out[x] represent coefficients of the output vector for use in forming an output block, where x is an integer variable from 0 to 7, and further wherein bitwise operator y>>z represents an arithmetic right shift of y by z binary digits.