Quantization in video coding

Patent metadata

Field	Value
Publication number	US-10298939-B2
Application number	US-201213529508-A
Country	US
Kind code	B2
Filing date	Jun 21, 2012
Priority date	Jun 22, 2011
Publication date	May 21, 2019
Grant date	May 21, 2019

Abstract

In an example, aspects of this disclosure relate to a method of coding video data that includes identifying a plurality of quantization parameter (QP) values associated with a plurality of reference blocks of video data. The method also includes generating a reference QP for the plurality of reference blocks based on the plurality of QPs. The method also includes storing the reference QP, and coding a block of video data based on the stored reference QP.

First claim

The invention claimed is:

1. A method of coding video data comprising:
identifying a plurality of quantization parameters (QPs) associated with a plurality of reference blocks of video data;
generating a reference QP for the plurality of reference blocks based on the plurality of QPs;
replacing the plurality of QPs associated with the plurality of reference blocks with the reference QP in memory; and
coding a block of video data based on the reference QP.

2. The method of claim 1 , wherein generating the reference QP comprises generating an average QP based on the plurality of QPs.

3. The method of claim 2 , wherein generating the average QP comprises calculating an average of the plurality of QPs associated with the plurality of reference blocks.

4. The method of claim 3 , wherein generating the average QP comprises generating the average QP based on the equation:

[

∑

k
=
0

N
-
1

⁢

QP
k

+

N
2

N

]

where N comprises the number of QPs of the plurality of QPs and QP k comprises each of the number of QPs being averaged.

5. The method of claim 1 , wherein generating the reference QP comprises selecting a representative QP from the plurality of QPs associated with the plurality of reference blocks.

6. The method of claim 1 , wherein identifying the plurality of QPs associated with the plurality of reference blocks comprises identifying the plurality of reference blocks in a predefined area of a reference picture, wherein the reference picture is associated with a different temporal instance than a picture that contains the block.

7. The method of claim 6 , wherein the predefined area comprises one of a 16×16 area, a 32×32 area, and a 64×64 area.

8. The method of claim 1 , wherein coding the block comprises encoding the block, and wherein encoding the block further comprises:
determining an actual QP for quantizing transform coefficients of the block;
determining a delta QP based on a difference between the actual QP and the reference QP; and
generating a bitstream to include an indication of the delta QP.

9. The method of claim 1 , wherein coding the block comprises decoding the block, and wherein decoding the block further comprises:
determining an actual QP for inverse quantizing transform coefficients of the block based on a combination of a received delta QP for the block and the reference QP; and
inverse quantizing the transform coefficients using the determined actual QP.

10. An apparatus for coding video data, the apparatus comprising:
a memory configured to store a plurality of quantization parameters (QPs) associate with a plurality of reference blocks of video data; and
one or more processors, the one or more processors configured to:
identify the plurality of QPs associated with the plurality of reference blocks of video data;
generate a reference QP for the plurality of reference blocks based on the plurality of QPs;
replace the plurality of QPs associated with the plurality of reference blocks with the reference QP in the memory; and
code a block of video data based on the reference QP.

11. The apparatus of claim 10 , wherein the one or more processors are configured to generate the reference QP by generating an average QP based on the plurality of QPs.

12. The apparatus of claim 11 , wherein the one or more processors are configured to generate the average QP by calculating an average of the plurality of QPs associated with the plurality of reference blocks.

13. The apparatus of claim 12 , wherein the one or more processors are configured to generate the average QP by generating the average QP based on the equation:

[

∑

k
=
0

N
-
1

⁢

QP
k

+

N
2

N

]

where N comprises the number of QPs of the plurality of QPs and QP k comprises each of the number of QPs being averaged.

14. The apparatus of claim 10 , wherein the one or more processors are configured to generate the reference QP by selecting a representative QP from the plurality of QPs associated with the plurality of reference blocks.

15. The apparatus of claim 10 , wherein the one or more processors are configured to identify the plurality of QPs associated with the plurality of reference blocks by identifying the plurality of reference blocks in a predefined area of a reference picture, wherein the reference picture is associated with a different temporal instance than a picture that contains the block.

16. The apparatus of claim 10 , wherein the apparatus comprises a video encoder, and wherein the one or more processors are further configured to:
determine an actual QP for quantizing transform coefficients of the block;
determine a delta QP based on a difference between the actual QP and the reference QP; and
generate a bitstream to include an indication of the delta QP.

17. The apparatus of claim 10 , wherein the apparatus comprises a video decoder, and wherein the one or more processors are further configured to:
determine an actual QP for inverse quantizing transform coefficients of the block based on a combination of a received delta QP for the block and the reference QP; and
inverse quantize the transform coefficients using the determined actual QP.

18. An apparatus for coding video data comprising:
means for identifying a plurality of quantization parameters (QPs) associated with a plurality of reference blocks of video data;
means for generating a reference QP for the plurality of reference blocks based on the plurality of QPs;
means for replacing the plurality of QPs associated with the plurality of reference blocks with the reference QP in memory; and
means for coding a block of video data based on the reference QP.

19. The apparatus of claim 18 , wherein the means for generating the reference QP comprises means for generating an average QP based on the plurality of QPs.

20. The apparatus of claim 19 , wherein the means for generating the average QP comprises means for calculating an average of the plurality of QPs associated with the plurality of reference block

Assignees

• Coban Muhammed Zeyd
• Karczewicz Marta
• Chong In Suk
• Wang Xianglin
• Qualcomm Inc

Inventors

• Coban Muhammed Zeyd
• Karczewicz Marta
• Chong In Suk
• Wang Xianglin

Classifications

• H04N19/463

  by compressing encoding parameters before transmission · CPC title

• H04N19/90

  using coding techniques not provided for in groups H04N19/10-H04N19/85, e.g. fractals · CPC title

• H04N19/61

  in combination with predictive coding · CPC title

• H04N19/196 Primary

  being specially adapted for the computation of encoding parameters, e.g. by averaging previously computed encoding parameters (processing of motion vectors H04N19/513) · CPC title

• H04N19/176

  the region being a block, e.g. a macroblock · CPC title