Indicating intra-prediction mode selection for video coding

摘要

For a block of video data, a video encoder can signal to a video decoder a selected intra-prediction mode using a codeword that is mapped to a modified intra-prediction mode index. The video decoder can receive the codeword, determine the modified intra-prediction mode index corresponding to the codeword, determine most probable modes based on a context, map the modified intra-prediction mode index to an intra-prediction mode index by comparing the modified intra-prediction mode index to the mode indexes of the most probable modes, and determine the selected intra-prediction mode used to encode the block of video data based on the intra-prediction mode index.

主权项

1. A method of decoding video data, the method comprising:
determining a first most probable intra-prediction mode and a second most probable intra-prediction mode for a coded block of video data based on a context for the current block; receiving an entropy encoded codeword corresponding to a modified intra-prediction mode index; determining an intra-prediction mode index based on the modified intra-prediction mode index, an intra-prediction mode index for the first most probable intra-prediction mode, and an intra-prediction mode index for the second most probable intra-prediction mode; selecting an intra-prediction mode other than the first most probable intra-prediction mode and second most probable intra-prediction mode to use to decode the coded block, wherein the selected intra-prediction mode corresponds to the determined intra-prediction mode index, wherein each of the intra-prediction modes corresponds to a respective intra-prediction mode index, and
when the modified intra-prediction mode index plus one is greater than or equal to the intra-prediction mode index for the first most probable intra-prediction mode and greater than or equal to the intra-prediction mode index for the second most probable intra-prediction mode, selecting the intra-prediction mode comprises selecting the intra-prediction mode corresponding to an intra-prediction mode index that is two greater than the modified intra-prediction mode index,when the modified intra-prediction mode index is less than the intra-prediction mode index for the first most probable intra-prediction mode and less than the intra-prediction mode index for the second most probable intra-prediction mode, selecting the intra-prediction mode comprises selecting the intra-prediction mode having an intra-prediction mode index equal to the modified intra-prediction mode index, andwhen the modified intra-prediction mode index plus one is greater than or equal to the intra-prediction mode index for the first most probable intra-prediction mode and less than the intra-prediction mode index for the second most probable intra-prediction mode, selecting the intra-prediction mode comprises selecting the intra-prediction mode corresponding to an intra-prediction mode index that is one greater than the modified intra-prediction mode index; and decoding the current block using the selected intra-prediction mode.