Patent ID: 8059721

Claim:
In a computing device that implements a video or image processing tool, a method comprising: transforming a video picture into a frequency domain; with the video or image processing tool, compensating for rounding in a DC coefficient of a set of transform coefficients associated with the frequency domain; with the video or image processing tool, estimating sample-domain distortion after compensating for rounding using the rounding-compensated DC coefficient and other transform coefficients of the set of transform coefficients by computing a difference between an original value of the DC coefficient and the rounded-compensated DC coefficient; with the video or image processing tool, making a decision based at least in part on the estimated distortion to select between intra encoding and inter encoding; and outputting, from the video or image processing tool, results that are based at least in part on the decision; wherein the compensating uses a rounding offset table, wherein a mapping of de-quantized values to offsets for the DC coefficient exhibits periodicity, and wherein the table maps representative de-quantized values to representative offsets for less than all of the de-quantized values.