an acceleration device comprising hardware logic to receive a stream of video frames to be encoded, to divide each video frame in the stream into multiple blocks, and to compute an intra-prediction cost associated with intra-coding of the blocks in each video frame; and

a control unit to compute, in software, an estimate of motion in each video frame relative to a reference frame in the stream, to compute, responsively to the estimate of motion, an inter-prediction cost associated with inter-coding of the blocks in each video frame, to make a comparison between the intra-prediction cost and the inter-prediction cost for each video frame, and to select, responsively to the comparison, an encoding mode for each video frame from a set of encoding modes consisting of inter-coding in software by the control unit and intra-coding by the hardware logic,

wherein the acceleration device is to compute an intra-prediction hint with respect to one or more angles for intra-coding of each block, and the control unit is to apply the intra-prediction hint in specifying an angle for intra-coding each of the blocks, and the acceleration device is to intra-code the blocks in the intra-coding mode such that pixels in each of the blocks are propagated along the angle specified by the control unit, and

wherein the acceleration device is to compute a map of motion vector prediction, for application by the control unit in inter-coding of the video frames.