SIGNALING OF DOWNSAMPLING FILTERS FOR CHROMA FROM LUMA INTRA PREDICTION MODE

原文（中文）

An example method of video coding includes receiving a video bitstream comprising a plurality of blocks including a chroma block. When a chroma-from-luma (CfL) intra prediction mode is enabled for the chroma block, a syntax element is parsed from the video bitstream, the syntax element indicating which downsampling filter to use for the chroma block. The method also includes selecting a downsampling filter from a plurality of downsampling filters according to the syntax element, where the plurality of downsampling filters include a 6-tap downsampling filter and a 4-tap downsampling filter. The method further includes determining luma sample positions associated with the chroma block based on the selected downsampling filter, and downsampling a plurality of luma samples at the luma sample positions, wherein pixels in each downsampled luma sample are co-located with corresponding pixels in the chroma block.