Chroma quantization parameter extension

Patent metadata

Field	Value
Publication number	US-10750176-B2
Application number	US-201916239010-A
Country	US
Kind code	B2
Filing date	Jan 3, 2019
Priority date	Jan 20, 2012
Publication date	Aug 18, 2020
Grant date	Aug 18, 2020

Abstract

The quantization parameters (QP) for Chroma are extended up to and more preferably to the same range as Luma QP (e.g., 0 to 51). Previous, values of Chroma QP only extended up to 39. Techniques are provided for determining extended Chroma QP values (e.g., for Cr and Cb) based on the Luma QP and picture level chroma offsets. In one preferred embodiment, slice level offsets are added making the method particularly well-suited for slice level parallel processing. The extension of Chroma QP enhances functionality, flexibility and friendliness of the High Efficiency Video Coding (HEVC) standard for various applications.

First claim

What is claimed is:

1. A decoding apparatus, comprising: circuitry configured to:
decode a bit stream that includes a slice level chroma quantization parameter (QP) offset;
obtain the slice level chroma QP offset from the bit stream;
clip a chroma QP within a chroma QP range from 0 to 51, based on a picture level chroma QP offset and the slice level chroma QP offset added to a luma QP, wherein the luma QP is in a range from 0 to 51;
obtain quantization data from the bit stream; and
inverse quantize the quantization data, based on the chroma QP.

2. The decoding apparatus of claim 1 ,
wherein the slice level chroma QP offset is included in the bit stream as a slice header syntax, and
wherein the circuitry is further configured to obtain the slice level chroma QP offset from the slice header syntax.

3. The decoding apparatus of claim 2 ,
wherein the picture level chroma QP offset is included in the bit stream as a picture parameter set syntax, and
wherein the circuitry is further configured to obtain the picture level chroma QP offset from the picture parameter set syntax.

4. The decoding apparatus of claim 1 , wherein the circuitry is further configured to: generate transform data based on the inverse quantization of the quantization data; and execute inverse orthogonal-transformation on the transform data.

5. A decoding method, comprising:
decoding, by a decoding apparatus, a bit stream that includes a slice level chroma quantization parameter (QP) offset;
obtaining, by the decoding apparatus, the slice level chroma QP offset from the bit stream;
clipping, by the decoding apparatus, a chroma QP within a chroma QP range from 0 to 51, based on a picture level chroma QP offset and the slice level chroma QP offset added to a luma QP, wherein the luma QP is in a range from 0 to 51;
obtaining, by the decoding apparatus, quantization data from the bit stream; and
inverse quantizing, by the decoding apparatus, the quantization data based on the chroma QP.

6. The decoding method of claim 5 , further comprising obtaining, by the decoding apparatus, the slice level chroma QP offset from a slice header syntax of the bit stream, wherein the slice level chroma QP offset is included in the slice header syntax of the bit stream.

7. The decoding method of claim 5 , further comprising:
obtaining, by the decoding apparatus, the picture level chroma QP offset from a picture parameter set syntax of the bit stream,
wherein the picture level chroma QP offset is included in the picture parameter set syntax of the bit stream.

8. The decoding method of claim 5 , further comprising:
generating, by the decoding apparatus, transform data based on the inverse quantization of the quantization data; and
executing, by the decoding apparatus, inverse orthogonal-transformation on the transform data.

9. At least one non-transitory computer-readable medium encoded with instructions that, when executed by a processor, causes the processor to perform:
decoding a bit stream that includes a slice level chroma quantization parameter (QP) offset;
obtaining the slice level chroma QP offset from the bit stream;
clipping a chroma QP within a chroma QP range from 0 to 51, based on a picture level chroma QP offset and the slice level chroma QP offset added to a luma QP, wherein the luma QP is in a range from 0 to 51;
obtaining quantization data from the bit stream; and
inverse quantizing the quantization data based on the chroma QP.

10. The at least one non-transitory computer-readable medium of claim 9 , wherein the instructions further cause the processor to perform:
obtaining the slice level chroma QP offset from a slice header syntax of the bitstream, wherein the slice level chroma QP offset is included in the slice header syntax of the bit stream.

11. The at least one non-transitory computer-readable medium of claim 9 , wherein the instructions further cause the processor to perform:
obtaining the picture level chroma QP offset from a picture parameter set syntax of the bit stream,
wherein the picture level chroma QP offset is included in the picture parameter set syntax of the bit stream.

12. The at least one non-transitory computer-readable medium of claim 9 , wherein the instructions further cause the processor to perform setting the chroma QP based on a mapping table that maps the chroma QP to the parameter.

13. The at least one non-transitory computer-readable medium of claim 9 , wherein the instructions further cause the processor to perform:
generating transform data based on the inverse quantization of the quantization data; and
executing inverse orthogonal-transformation on the transform data.

Assignees

• Velos Media Llc

Inventors

• Xu Jun
• Sato Kazushi
• Maani Ehsan

Classifications

• H04N19/149

  by estimating the code amount by means of a model, e.g. mathematical model or statistical model · CPC title

• H04N19/107

  between spatial and temporal predictive coding, e.g. picture refresh · CPC title

• H04N19/124 Primary

  Quantisation · CPC title

• H04N19/186 Primary

  the unit being a colour or a chrominance component · CPC title

• H04N19/174

  the region being a slice, e.g. a line of blocks or a group of blocks · CPC title