Palette coding for non-4:4:4 screen content video

A method for palette encoding a video, the method comprising:

• receiving a video block associated with a first chroma format, the video block comprising a plurality of chroma sample positions and a plurality of luma sample positions;
• upsampling the plurality of chroma sample positions in accordance with a second chroma format;
• deriving a palette table and a palette index map associated with the second chroma format based on the upsampled plurality of chroma sample positions and the plurality of luma sample positions;
• and
• encoding the palette table and the palette index map associated with the second chroma format in a video bit-stream, wherein the palette index map is associated with luma and chroma sample values of the second chroma format.

A video coding device for palette decoding a video bit-stream associated with a first chroma format, the video coding device comprising:

• a processor configured to:
• receive data defining a palette table and a palette index map associated with a coding unit (CU), the palette table and the palette index map being associated with a second chroma format, wherein the palette index map is associated with luma and chroma sample values of the second chroma format;
• for a first chroma sample position associated with the first chroma format, derive a chroma sample position associated with the second chroma format on the palette index map associated with the second chroma format based on a luma component to chroma component resolution ratio associated with the first chroma format;
• and
• determine a respective chroma sample value for the chroma sample position associated with the first chroma format based on the derived chroma sample position associated with the second chroma format, the palette index map associated with the second chroma format, and the palette table.