ENCODING/DECODING OF HIGH CHROMA RESOLUTION DETAILS

Innovations in encoding and decoding of video pictures in a high-resolution chroma sampling format (such as YUV 4:4:4) using a video encoder and decoder operating on coded pictures in a low-resolution chroma sampling format (such as YUV 4:2:0) are presented. For example, high chroma resolution details are selectively encoded on a region-by-region basis. Or, as another example, coded pictures that contain sample values for low chroma resolution versions of input pictures and coded pictures that contain sample values for high chroma resolution details of the input pictures are encoded as separate sub-sequences of a single sequence of coded pictures, which can facilitate effective motion compensation. In this way, available encoders and decoders operating on coded pictures in the low-resolution chroma sampling format can be effectively used to provide high chroma resolution details.