METHOD AND APPARATUS FOR CALCULATING AN SSD AND ENCODING A VIDEO SIGNAL

The present invention relates to a method and apparatus for calculating the Sum of Squared Differences (SSD) between a source block and a reconstructed block of image or video data encoding according to an encoding scheme such as H.264/AVC. In a preferred embodiment, the method computes the SSD by finding the SSD between coefficients of an integer transformed residual block and the corresponding inverse-quantized coefficients. Preferably the inverse quantized coefficients are found with the aid of a look up table. This method may save computing time and processing power compared to calculating the SSD directly from the source and reconstructed blocks. The SSD is related to the distortion caused by encoding and the method may be used in calculating the rate-distortion of a particular encoding mode. One embodiment of the invention encodes a block of data by selecting the encoding mode with the least rate-distortion.