Patent ID: 6810083
Filing Date: 2004-10-26
Classification: H04N

Abstract:
A method for evaluating the quality of encoded video data, the method comprising the steps of:decoding at least a substantial portion of said encoded video data to produce decompressed video data including a plurality of blocks; performing a discrete cosine transform (DCT) on said decompressed video data to produce a set of DCT coefficients for at least one AC frequency band; simultaneously, extracting quantization matrix data for the at least one AC frequency band and extracting a quantizer scale for each block of said decompressed video data; estimating a variance of said DCT coefficients; determining an average quantization error for each set of said DCT coefficients based on said variance, said quantization matrix, and said quantizer scale; and, calculating a peak signal to noise ratio (PSNR) based on said average quantization error.