Patent ID: 9392287
Filing Date: 2016-07-12
CPC Classification: H04N

Claim Text:
1. A method of decoding a chroma image, comprising: deriving a chroma intra prediction mode of a prediction unit; determining a size of a chroma prediction block using luma transform size information; generating the chroma prediction block using the chroma intra prediction mode; generating a chroma residual block using the chroma intra prediction mode and a chroma quantization parameter; and generating a chroma reconstructed block by adding the chroma prediction block and the chroma residual block, wherein the chroma quantization parameter is generated using a luma quantization parameter determined per quantization unit and information indicating a relationship between the luma quantization parameter and the chroma quantization parameter, the luma quantization parameter is generated using a luma quantization parameter predictor and a luma differential quantization parameter, if both of a left luma quantization parameter and an above luma quantization parameter are available, an average of the left luma quantization parameter and the above luma quantization parameter is set as the luma quantization parameter predictor, and if only one of the left luma quantization parameter and the above luma quantization parameter is available, an average of the available luma quantization parameter and the previous luma quantization parameter is set as the luma quantization parameter predictor.