Qp derivation and offset for adaptive color transform in video coding

Patent metadata

Field	Value
Publication number	US-2016100168-A1
Application number	US-201514876594-A
Country	US
Kind code	A1
Filing date	Oct 6, 2015
Priority date	Oct 7, 2014
Publication date	Apr 7, 2016
Grant date	—

Abstract

A device for decoding video data is configured to determine, based on a chroma sampling format for the video data, that adaptive color transform is enabled for one or more blocks of the video data; determine a quantization parameter for the one or more blocks based on determining that the adaptive color transform is enabled; and dequantize transform coefficients based on the determined quantization parameter. A device for decoding video data is configured to determine for one or more blocks of the video data that adaptive color transform is enabled; receive in a picture parameter set, one or more offset values in response to adaptive color transform being enabled; determine a quantization parameter for a first color component of a first color space based on a first of the one or more offset values; and dequantize transform coefficients based on the quantization parameter.

First claim

What is claimed is:

1 . A method of decoding video data, the method comprising:
determining, based on a chroma sampling format for the video data, that adaptive color transform is enabled for one or more blocks of the video data; determining a quantization parameter for the one or more blocks based on determining that the adaptive color transform is enabled; and dequantizing transform coefficients based on the determined quantization parameter.

2 . The method of claim 1 , further comprising:
determining for one or more second blocks of the video data that a chroma sampling format for the video blocks is a chroma sampling format other than 4:4:4; based on the chroma sampling format being other than 4:4:4, determining that adaptive color transform is disabled for the second one or more blocks.

3 . The method of claim 2 , wherein determining that adaptive color transform is disabled for the second one or more blocks comprises determining that adaptive color transform is disabled for the second one or more blocks without receiving a syntax element, other than the indication of the chroma sampling format, indicating if adaptive color transform is disabled.

4 . The method of claim 1 , wherein determining that adaptive color transform is enabled for one or more blocks of the video data comprises determining the chroma sampling format is a 4:4:4 sampling format.

5 . The method of claim 4 , further comprising:
in response to determining the chroma sampling format is a 4:4:4 sampling format, receiving a syntax element indicating if adaptive color transform is enabled for the one or more blocks of the video data, wherein determining that adaptive color transform is enabled for the one or more blocks of the video data is further based on the syntax element indicating adaptive color transform is enabled for the one or more blocks of the video data.

6 . A device for decoding video data, the device comprising:
a video data memory; one or more processors configured to:
determine, based on a chroma sampling format for the video data, that adaptive color transform is enabled for one or more blocks of the video data;
determine a quantization parameter for the one or more blocks based on determining that the adaptive color transform is enabled; and
dequantize transform coefficients based on the determined quantization parameter.

7 . The device of claim 6 , wherein the one or more processors are further configured to:
determine for one or more second blocks of the video data that a chroma sampling format for the video blocks is a chroma sampling format other than 4:4:4; determine that adaptive color transform is disabled for the second one or more blocks based on the chroma sampling format being other than 4:4:4.

8 . The device of claim 7 , wherein to determine that adaptive color transform is disabled for the second one or more blocks, the one or more processors are further configured to determine that adaptive color transform is disabled for the second one or more blocks without receiving a syntax element, other than the indication of the chroma sampling format, indicating if adaptive color transform is disabled.

9 . The device of claim 6 , wherein to determine that adaptive color transform is enabled for one or more blocks of the video data, the one or more processors are further configured to determine the chroma sampling format is a 4:4:4 sampling format.

10 . The device of claim 9 , wherein the one or more processors are further configured to:
in response to determining the chroma sampling format is a 4:4:4 sampling format, receive a syntax element indicating if adaptive color transform is enabled for the one or more blocks of the video data, wherein determining that adaptive color transform is enabled for the one or more blocks of the video data is further based on the syntax element indicating adaptive color transform is enabled for the one or more blocks of the video data.

11 . The device of claim 6 , wherein the device comprises at least one of:
an integrated circuit; a microprocessor; or a wireless communication device.

12 . The device of claim 6 , wherein the device comprises a wireless communication device, further comprising:
a receiver configured to receive encoded video data.

13 . The device of claim 12 , wherein the wireless communication device comprises a telephone, wherein the receiver is configured to receive the encoded video data in a signal modulated according to a wireless telecommunication standard.

14 . An apparatus for decoding video data, the apparatus comprising:
means for determining, based on a chroma sampling format for the video data, that adaptive color transform is enabled for one or more blocks of the video data; means for determining a quantization parameter for the one or more blocks based on determining that the adaptive color transform is enabled; and means for dequantizing transform coefficients based on the determined quantization parameter.

15 . A computer readable medium storing instructions that when executed by one or more processors cause the one or more processors to:
determine, based on a chroma sampling format for the video data, that adaptive color transform is enabled for one or more blocks of the video data; determine a quantization parameter for the one or more blocks based on determining that the adaptive color transform is enabled; and dequantize transform coefficients based on the determined quantization parameter.

16 . A method of decoding video data, the method comprising:
determining for one or more blocks of the video data that adaptive color transform is enabled; receiving in a picture parameter set, one or more offset values in response to adaptive color transform being enabled; determining a quantization parameter for a first color component of a first color space based on a first of the one or more offset values; and dequantizing transform coefficients based on the quantization parameter.

17 . The method of claim 16 , wherein the one or more offset values comprise an offset value for the first color component, an offset value for a second color component, and an offset value for a third color component.

18 . The method of claim 16 , further comprising:
determining a quantization parameter for a first color component of a second color space, and wherein determining the quantization parameter for the first color component of the first color space based on the first of the one or more offset values comprises converting the quantization parameter for the first color component of the second color space to the quantization parameter for the first color component of the first color space by adding the first of the one or more offset values to the quantization parameter for the first color component of the second color space.

19 . The method of claim 18 , wherein the first color space comprises an RGB color space, and wherein the second color space comprise a YCbCr color space.

20 . The method of claim 16 , wherein the one or more offset values comprises a first set of offset values, the method further comprising:
receiving in a slice header, a second set of offset values.

21 . The method of claim 16 , wherein determining for one or more blocks of the video data that adaptive color transform is enabled comprises receiving an indication of a chroma sampling format for the one or more blocks and, based on the chroma sampling format, determining that adaptive color transform is e

Assignees

• Qualcomm Inc

Inventors

• Rapaka Krishnakanth
• Zhang Li
• Joshi Rajan Laxman
• Karczewicz Marta

Classifications

• H04N19/60

  using transform coding · CPC title

• H04N19/186

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

• H04N19/176

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

• H04N19/18

  the unit being a set of transform coefficients · CPC title

• H04N19/12 Primary

  Selection from among a plurality of transforms or standards, e.g. selection between discrete cosine transform [DCT] and sub-band transform or selection between H.263 and H.264 · CPC title