US 2026/0039879 A1 · SIGNALING OF DOWNSAMPLING FILTERS FOR CHROMA FROM LUMA INTRA PREDICTION MODE

Abstract

Methods and apparatuses for performing cross-component intra prediction, including: receiving a coded bitstream; obtaining, from the coded bitstream, a syntax element indicating a downsampling filter used for a cross-component intra prediction mode; obtaining a plurality of reconstructed sample values of a first component which are associated with a pixel of a second component based on the downsampling filter; determining a pixel value of a downsampled pixel of the first component, based on the plurality of reconstructed sample values; determining a pixel value of the pixel of the second component based on the pixel value of the downsampled pixel of the first component; and reconstructing a picture based on the pixel value of the pixel of the second component.

Claims20

Dependent claims

A method for video decoding, the method comprising:

receiving a video bitstream comprising a current picture;
determining a current chroma block of the current picture;
determining that a cross-component intra prediction mode is selected for video coding;
based on determining that the cross-component mode is selected and based on a multi-tap downsampling filter being supported, determining pixel values of a plurality of downsampled luma samples for a plurality of chroma samples using a first equation that is associated with the multi-tap downsampling filter being supported, wherein the first equation is based on the multi-tap filter being used, pixel values at specific positions, and a rounding value;
and
decoding the current chroma block based on at least the plurality of downsampled luma samples.

3 more elements

A method for video encoding, the method comprising:

receiving video data comprising a current picture;
determining a current chroma block of the current picture;
determining that a cross-component intra prediction mode is selected for video coding;
based on determining that the cross-component mode is selected and based on a multi-tap downsampling filter being supported, determining pixel values of a plurality of downsampled luma samples for a plurality of chroma samples using a first equation that is associated with the multi-tap downsampling filter being supported, wherein the first equation is based on the multi-tap filter being used, pixel values at specific positions, and a rounding value;
and
encoding the current chroma block in a video bitstream and based on at least the plurality of downsampled luma samples.

3 more elements

A non-transitory computer-readable storage medium storing a video bitstream that is generated by a video encoding method, the video encoding method comprising:

receiving video data comprising a current picture;
determining a current chroma block of the current picture;
determining that a cross-component intra prediction mode is selected for video coding;
based on determining that the cross-component mode is selected and based on a multi-tap downsampling filter being supported, determining pixel values of a plurality of downsampled luma samples for a plurality of chroma samples using a first equation that is associated with the multi-tap downsampling filter being supported, wherein the first equation is based on the multi-tap filter being used, pixel values at specific positions, and a rounding value;
and
encoding the current chroma block in a video bitstream and based on at least the plurality of downsampled luma samples.

3 more elements

Dependencies are inferred from the claim text.

Signaling of downsampling filters for chroma from luma intra prediction mode

Life of this patent

Signaling of downsampling filters for chroma from luma intra prediction mode

Life of this patent

Abstract

Claims20