Image processing device and method
An image processing device and method that enable suppression of a reduction in coding efficiency. The image processing device encodes an image to generate encoded data, and set, as syntax of the generated encoded data, syntax whose semantics is set so that a default quantization matrix having the same size as a block size that is a unit of processing in which quantization is performed is referred to when in a copy mode in which a quantization matrix is copied, quantization matrix reference data identifying a reference destination of the quantization matrix matches quantization matrix identification data identifying the quantization matrix. The device and method can be applied to an image processing device.
1. An image processing device comprising:
circuitry configured to
set, in a case a current quantization matrix is copied, as syntax whose semantics is set so that default quantization matrix is referred to as a condition that a value is 0, a difference value between a value of identification information identifying a reference quantization matrix and a value of identification information identifying the current quantization matrix;
set, in a case the current quantization matrix is not copied, a replacement difference coefficient, which is a difference between a replacement coefficient used to replace a (0, 0) coefficient of a 16×16 quantization matrix and a (0, 0) coefficient of an 8×8 quantization matrix, the 16×16 quantization matrix being obtained by using a nearest neighboring process against the 8×8 quantization matrix for up-converting;
quantize transform coefficient data obtained by orthogonal transforming an image, and generate quantized data; and
encode the generated quantized data and the replacement difference coefficient to generate encoded data, the encoded data including the replacement difference coefficient and the difference value.
2. The image processing device according to claim 1 , wherein the circuitry is configured to:
set, in the case the current quantization matrix is not copied, a difference coefficient, which is a difference between each coefficient of the 8×8 quantization matrix; and
generate the encoded data including the difference coefficient.
3. The image processing device according to claim 2 , wherein the circuitry is configured to generate the encoded data whose syntax is a group of difference coefficients grouping the replacement difference coefficient and the difference coefficient.
4. The image processing device according to claim 3 , wherein the circuitry is configured to:
encode the replacement difference coefficient, and then encode the difference coefficient; and
generate the encoded data whose syntax is the group of difference coefficients.
5. The image processing device according to claim 4 , wherein
the circuitry is configured to:
set, in the case the current quantization matrix is not copied, an initial difference coefficient, which is a difference between the replacement coefficient and an initial value of a coefficient set to a quantization matrix; and
generate the encoded data including the initial difference coefficient.
6. The image processing device according to claim 5 , wherein the circuitry is configured to:
encode the initial difference coefficient, and then encode the group of difference coefficients; and
generate the encoded data whose syntax is the initial difference coefficient and the group of difference coefficients.
7. The image processing device according to claim 6 , wherein the circuitry is configured to:
encode the initial difference coefficient using signed exponential Golomb coding, and then encode the group of difference coefficients using the signed exponential Golomb coding; and
generate the encoded data whose syntax is the encoded initial difference coefficient and the encoded group of difference coefficients using the signed exponential Golomb coding.
8. The image processing device according to claim 7 , wherein the circuitry is configured to:
orthogonal transform the image to generate the transform coefficient data; and
quantize the generated transform coefficient data.
9. The image processing device according to claim 8 , wherein the circuitry is configured to:
orthogonal transform the image to generate the transform coefficient data using a transformation unit of 16×16; and
quantize the generated transform coefficient data using the 16×16 quantization matrix.
10. An image processing method comprising:
setting, in a case a current quantization matrix is copied, as syntax whose semantics is set so that default quantization matrix is referred to as a condition that a value is 0, a difference value between a value of identification information identifying a reference quantization matrix and a value of identification information identifying the current quantization matrix;
setting, in a case the current quantization matrix is not copied, a replacement difference coefficient, which is a difference between a replacement coefficient used to replace a (0, 0) coefficient of a 16×16 quantization matrix and a (0, 0) coefficient of an 8×8 quantization matrix, the 16×16 quantization matrix being obtained by using a nearest neighboring process against the 8×8 quantization matrix for up-converting;
quantizing transform coefficient data obtained by orthogonal transforming an image, and generate quantized data; and
encoding, using circuitry, the generated quantized data and the replacement difference coefficient to generate encoded data, the encoded data including the replacement difference coefficient and the difference value.
11. The image processing method according to claim 10 , wherein
the setting, in the case the current quantization matrix is not copied, sets a difference coefficient, which is a difference between each coefficient of the 8×8 quantization matrix, and
the encoding generates the encoded data including the difference coefficient.
12. The image processing method according to claim 11 , wherein the encoding generates the encoded data whose syntax is a group of difference coefficients grouping the replacement difference coefficient and the difference coefficient.
13. The image processing method according to claim 12 , wherein
the encoding encodes the replacement difference coefficient, and then encodes the difference coefficient, and
the encoding generates the encoded data whose syntax is the group of difference coefficients.
14. The image processing method according to claim 13 , wherein
the setting, in the case the current quantization matrix is not copied, sets an initial difference coefficient, which is a difference between the replacement coefficient and an initial value of a coefficient set to a quantization matrix, and
the encoding generates the encoded data including the initial difference coefficient.
15. The image processing method according to claim 14 , wherein
the encoding encodes the initial difference coefficient, and then encodes the group of difference coefficients, and
the encoding generates the encoded data whose syntax is the initial difference coefficient and the group of difference coefficients.
16. The image processing method according to claim 15 , wherein
the encoding encodes the initial difference coefficient using signed exponential Golomb coding, and then encodes the group of difference coefficients using the signed exponential Golomb coding; and
the encoding generates the encoded data whose syntax is the encoded initial difference coefficient and the encoded group of difference coefficients using the signed exponential Golomb coding.
17. The image processing method according to claim 16 , wherein
the method further comprising orthogonal transforming the image to generate the transform coefficient data, and
the quantizing quantizes the generated transform coefficient data.
18. The image processing method according to claim 17 , wherein
the orthogonal transforming orthogonal transforms the image to generate the transform coefficient data using a transformation unit of 16×16, and
the quantizing quantizes the generated transform coefficient data using the 16×16 quantization matrix.