CHROMA QUANTIZATION PARAMETER EXTENSION

• US 20160373751A1
• Filed: 08/31/2016
• Published: 12/22/2016
• Est. Priority Date: 01/20/2012
• Status: Active Grant

• Current Assignee: Sony Group Corp.
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: XU, JUN, MAANI, EHSAN, SATO, KAZUSHI
• Granted Patent: US 10,110,898 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04N 19/124 Quantisation
• CPC Class Codes: H04N 19/126 Details of normalisation or weighting functions, e.g. normalisation matrices or variable uniform quantisers
• CPC Class Codes: H04N 19/13 Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
• CPC Class Codes: H04N 19/147 according to rate distortion criteria rate-distortion as a criterion for motion estimation H04N19/567
• CPC Class Codes: H04N 19/149 by estimating the code amount by means of a model, e.g. mathematical model or statistical model
• CPC Class Codes: H04N 19/159 Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/174 the region being a slice, e.g. a line of blocks or a group of blocks
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/186 the unit being a colour or a chrominance component
• CPC Class Codes: H04N 19/436 using parallelised computational arrangements
• CPC Class Codes: H04N 19/61 in combination with predictive coding
• CPC Class Codes: H04N 19/70 characterised by syntax aspects related to video coding, e.g. related to compression standards
• CPC Class Codes: H04N 19/80 Details of filtering operations specially adapted for video compression, e.g. for pixel interpolation H04N19/635, H04N19/86 take precedence

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.

Claims

1. A decoding apparatus, comprising:

circuitry configured to;

set a chroma quantization parameter (QP) included in a range of chroma QP equal to a range of luma QP, based on a parameter with a picture level chroma QP offset added to a luma QP; and

inverse quantize quantization data that is decoded from a bit stream based on the set chroma QP.

2. The decoding apparatus of claim 1, wherein the luma QP ranges from 0 to 51, and the chroma QP ranges from 0 to 51.

3. The decoding apparatus of claim 1, wherein the circuitry is further configured to set the chroma QP, based on a mapping table that is configured to map the chroma QP to a parameter with the picture level chroma QP offset added to the luma QP.

4. The decoding apparatus of claim 3, wherein the circuitry is further configured to:

set a chroma QP for a first chroma component based on a parameter with a picture level chroma QP offset for the first chroma component added to a luma QP, and

set a chroma QP for a second chroma component based on a parameter with a picture level chroma QP offset for the second chroma component added to a luma QP.

5. The decoding apparatus of claim 4, wherein the circuitry is further configured to decode the bit stream to generate the quantization data.

6. A decoding method, comprising:

setting a chroma quantization parameter (QP) included in a range of chroma QP equal to a range of luma QP, based on a parameter with a picture level chroma QP offset added to a luma QP; and

performing inverse quantization on quantization data that is decoded from a bit stream, based on the set chroma QP.

7. The decoding method of claim 6, wherein the luma QP ranges from 0 to 51, and the chroma QP ranges from 0 to 51.

8. The decoding method of claim 6, further comprising setting the chroma QP based on a mapping table that is configured to map the chroma QP to a parameter with the picture level chroma QP offset added to the luma QP.

9. The decoding method of claim 8, further comprising:

setting a chroma QP for a first chroma component based on a parameter with a picture level chroma QP offset for the first chroma component added to a luma QP, and

setting a chroma QP for a second chroma component based on a parameter with a picture level chroma QP offset for the second chroma component added to a luma QP.

10. The decoding method of claim 9, further comprising decoding the bit stream to generate the quantization data.