Patent ID: 9143805
Filing Date: 2015-09-22
Classification: H04N

Abstract:
1. An image coding method of coding a chrominance signal, the image coding method comprising: generating an intra prediction chrominance signal of a current block according to an intra prediction mode; calculating a residual signal of the current block from the intra prediction chrominance signal of the current block and an input chrominance signal of the current block; performing transform and quantization on the residual signal of the current block to calculate quantized coefficients; performing inverse quantization and inverse transform on the quantized coefficients to calculate a coded residual signal of the current block; generating a temporarily coded chrominance signal of the current block, from the coded residual signal and the intra prediction chrominance signal of the current block; calculating a direct-current component of the input chrominance signal of the current block; calculating a direct-current component of the temporarily coded chrominance signal of the current block; calculating an offset value from the direct-current component of the input chrominance signal of the current block and the direct-current component of the temporarily coded chrominance signal of the current block; coding the quantized coefficients, the intra prediction mode, and the offset value; and adding the offset value to the temporarily coded chrominance signal of the current block to generate the coded chrominance signal of the current block.