Encoding functionality is described for producing encoded intra (I) pictures and predictive (P) pictures for consumption by an application running on a set-top box. The encoding functionality includes a pre-processing module which marks regions that should not be updated with a predetermined color code. An encoding module receives the output of the pre-processing module, and, in the event that the output contains the predetermined color code, produces a predictive (P) picture. In the predictive (P) picture, the encoding module produces macroblocks having zero motion vector and zero difference (or skipped macroblocks) corresponding to regions that were marked by the pre-processing module with the predetermined color code. The encoding module produces intra macroblocks for other regions of the picture (corresponding to update regions).