| CPC H04N 19/124 (2014.11) [H04N 19/176 (2014.11); H04N 19/186 (2014.11); H04N 19/70 (2014.11)] | 18 Claims |

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1. A method for inverse quantization of a current chrominance block of a picture, wherein the method is performed by a decoder, and the method comprising:
receiving a bitstream;
obtaining a value of a joint chrominance component residual (JCCR) control flag from the bitstream, wherein the JCCR control flag specifies whether joint coding of a cb chrominance component and a cr chrominance component is enabled or disabled;
obtaining a chrominance mapping information from the bitstream directly dependent on the value of the JCCR control flag;
obtaining at least one chrominance quantization parameter (QP) offset from the bitstream directly dependent on the value of the JCCR control flag;
obtaining a QP value for the current chrominance block based on the obtained chrominance mapping information and the at least one obtained chrominance QP offset; and
performing inverse quantization on the current chrominance block by using the obtained QP value.
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