INTRA PREDICTION MODE SELECTION IN VIDEO CODING

摘要

A method is provided for encoding a digital video with a video encoder that allows intra prediction of mode selection. The method includes dividing pixels from each intra prediction block into four groups based on phases of the pixels, progressively narrowing down a list of intra prediction modes over a series of stages based on a comparison of a cost value for each intra prediction mode at that stage against a threshold value, tentatively assigning the remaining intra prediction with the lowest cost value after the final stage to the block, calculating a heterogeneity index for each group of contiguous intra prediction blocks based on the tentative intra prediction mode selected for each block after the final stage, and finalizing the tentative intra prediction mode for each block if the group has a heterogeneity index above a predetermined threshold value.

主权项

1. A method of encoding a digital video with a video encoder, comprising:
loading a picture comprising a plurality of pixels; arranging said plurality of pixels into a plurality of intra prediction blocks and/or inter prediction blocks; dividing the pixels of each intra prediction block into a first group, a second group, a third group, and a fourth group based on phases of the pixels; for each intra prediction block, loading an initial list of intra prediction modes; at a first stage for each intra prediction block, calculating a first stage cost value for each of the intra prediction modes on said initial list for said first group, calculating a first stage threshold maximum cost, and generating a first stage mode list by copying each intra prediction mode on said initial mode list that has a first stage cost value that is less than said first stage threshold maximum cost; at a second stage for each intra prediction block, calculating a second stage cost value for each of the intra prediction modes on said first stage mode list for said second group, calculating a second stage threshold maximum cost, and generating a second stage mode list by copying each intra prediction mode on said first stage mode list that has a second stage cost value that is less than said second stage threshold maximum cost; at a third stage for each intra prediction block, calculating a third stage cost value for each of the intra prediction modes on said second stage mode list for said third group, calculating a third stage threshold maximum cost, and generating a third stage mode list by copying each intra prediction mode on said second stage mode list that has a third stage cost value that is less than said third stage threshold maximum cost; at a fourth stage for each intra prediction block, calculating a fourth stage cost value for each of the intra prediction modes on said third stage mode list for said fourth group; for each intra prediction block, selecting the intra prediction mode on said third stage mode list with the lowest fourth stage cost value as a tentative intra prediction mode for the intra prediction block; calculating a heterogeneity index for each group of contiguous intra prediction blocks in said picture, based on the tentative intra prediction mode selected for each intra prediction block after said fourth stage; and finalizing the tentative intra prediction mode for each intra prediction block within each group of contiguous intra prediction blocks that has a heterogeneity index above a predetermined threshold value.