Method and device for encoding/decoding residual block on basis of quantization parameter
An encoding/decoding device according to the present invention derives a residual coefficient of a residual block from a bitstream, calculates a quantization parameter for the residual block, performs inverse quantization on the residual coefficient by using the quantization parameter, and performs inverse conversion on the inversely quantized residual coefficient, thereby enabling restoration of a residual sample of the residual block.
1. A method of decoding a video signal, performed by a decoding apparatus, the method comprising:
deriving a residual coefficient of a residual block;
calculating a quantization parameter for the residual block;
performing inverse-quantization on the residual coefficient using the calculated quantization parameter; and
reconstructing a residual sample of the residual block by performing inverse-transform on the inverse quantized residual coefficient,
wherein an encoded residual coefficient for a partial region in the residual block is not transmitted from an encoding apparatus,
wherein a residual sample of the partial region in the residual block is set equal to a default value pre-defined at the decoding apparatus,
wherein the partial region is representative of a region excluding at least one of N columns from a left side of the residual block or M rows from a top side of the residual block, and
wherein the quantization parameter is derived based on a quantization parameter prediction value of the residual block, the quantization parameter prediction value being derived based on a quantization parameter of a neighboring block adjacent to the residual block.
2. The method of claim 1 ,
wherein the N and the M are derived based on information coded to specify a size or a position of the partial region.
3. The method of claim 1 ,
wherein the residual block is divided into a variable size/shape based on at least one of a quad tree, a binary tree, or a triple tree.
4. The method of claim 1 ,
wherein the default value is 0.
5. A method of encoding a video, performed by an encoding apparatus, the method comprising:
performing a transform on a residual sample of a residual block to obtain a transform coefficient of the residual block;
performing a quantization on the transform coefficient of the residual block based on a quantization parameter to obtain a quantized transform coefficient of the residual block; and
generating a bitstream by encoding the quantized transform coefficient,
wherein a residual coefficient for a partial region in the residual block is not encoded,
wherein a residual sample of the partial region in the residual block is set equal to a default value pre-defined at the encoding apparatus,
wherein the partial region is representative of a region excluding at least one of N columns from a left side of the residual block or M rows from a top side of the residual block, and
wherein the quantization parameter is derived based on a quantization parameter prediction value of the residual block, the quantization parameter prediction value being derived based on a quantization parameter of a neighboring block adjacent to the residual block.
6. A method of transmitting a bitstream, comprising:
performing a transform on a residual sample of a residual block to obtain a transform coefficient of the residual block;
performing a quantization on the transform coefficient of the residual block based on a quantization parameter to obtain a quantized transform coefficient of the residual block; and
generating the bitstream by encoding the quantized transform coefficient; and
transmitting the bitstream,
wherein a residual coefficient for a partial region in the residual block is not encoded,
wherein a residual sample of the partial region in the residual block is set equal to a default value pre-defined at an encoding apparatus,
wherein the partial region is representative of a region excluding at least one of N columns from a left side of the residual block or M rows from a top side of the residual block, and
wherein the quantization parameter is derived based on a quantization parameter prediction value of the residual block, the quantization parameter prediction value being derived based on a quantization parameter of a neighboring block adjacent to the residual block.