Abstract: A video encoding system generates (e.g., H.264) single-slice pictures using parallel processors. Each picture is divided horizontally into multiple segments, where each different parallel processor processes a different segment. Each parallel processor (other than the first parallel processor of the uppermost segment) only partially processes the macroblocks in the first row of its segment. Subsequently, a final processor completes the processing of the partially encoded, first-row macroblocks based on the encoding results for the macroblocks in the last row of the segment above and across the segment boundary. The encoding of the first-row macroblocks is constrained to enable the encoding of all other rows of macroblocks to be completed by the parallel processors, without relying on the final processor.