Parsing dependency reduction for palette index coding

Patent metadata

Field	Value
Publication number	US-10158866-B2
Application number	US-201514864331-A
Country	US
Kind code	B2
Filing date	Sep 24, 2015
Priority date	Sep 26, 2014
Publication date	Dec 18, 2018
Grant date	Dec 18, 2018

Abstract

In an example, a method of processing video data includes determining an input parameter for a truncated binary code that represents a palette index for a pixel of a block of video data based on a number of indices in a palette for the block. The method also includes coding a prefix of the truncated binary code, and determining a palette coding mode for the pixel from a first palette coding mode and a second palette coding mode based only on the prefix of the truncated binary code.

First claim

What is claimed is:

1. A method of processing video data, the method comprising:
determining a palette for a palette-coded block of the video data, the palette including one or more palette entries, each respective palette entry representing a respective palette index;
determining, based on a total number of indices represented by the palette entries of the palette determined for the palette-coded block, an input parameter for a truncated binary code that includes a prefix and a suffix, wherein the suffix of the truncated binary code represents the respective palette index for a pixel of the palette-coded block of the video data;
coding the prefix of the truncated binary code; and
selecting between a first palette coding mode and a second palette coding mode based only on the prefix of the truncated binary code to determine a palette coding mode with which to code the pixel of the palette-coded block.

2. The method of claim 1 , wherein coding the prefix comprises determining that the prefix has all bins set equal to zero, and wherein selecting between the first palette coding mode and the second palette coding mode comprises selecting the first palette coding mode based on the prefix having all bins set equal to zero.

3. The method of claim 2 , wherein the first palette coding mode is an escape palette coding mode, the method further comprising coding a pixel value for the pixel based on the suffix of the truncated binary code.

4. The method of claim 3 , wherein coding the pixel value comprises coding the suffix after coding the prefix to determine the palette coding mode with which to code the pixel.

5. The method of claim 1 , wherein selecting between the first palette coding mode and the second palette coding mode comprises selecting the second palette coding mode, the method further comprising coding data positioned between the prefix and the suffix of the truncated binary code to code data that indicates a run length of subsequent pixels to be coded with the pixel.

6. The method of claim 5 , wherein coding the data that indicates the run length comprises coding the data that indicates the run length after coding the prefix of the truncated binary code, the method further comprising coding the suffix of the truncated binary code after coding the data that indicates the run length.

7. The method of claim 5 , the method further comprising coding the suffix of the truncated binary code in parallel with coding the data that indicates the run length.

8. The method of claim 1 , wherein determining the input parameter for the truncated binary code based on the total number of indices represented by the palette entries of the palette comprises determining the input parameter for the truncated binary code based only on the total number of indices represented by the palette entries of the palette.

9. The method of claim 8 , wherein determining the input parameter for the truncated binary code based only on the total number of indices represented by the palette entries of the palette comprises determining the input parameter for the truncated binary code by solving the following equation, L=└log 2 (N+2)┘, where L represents the input parameter and N represents the number of indices.

10. The method of claim 1 , wherein selecting between the first palette coding mode and the second palette coding mode based only on the prefix comprises determining the palette coding mode prior to coding the suffix of the truncated binary code.

11. The method of claim 1 , wherein coding comprises encoding, and wherein encoding the prefix of the truncated binary code comprises generating a portion of an encoded bitstream that includes the prefix of the truncated binary code.

12. The method of claim 1 , further comprising receiving an encoded video bitstream that includes the prefix of the truncated binary code, wherein coding comprises decoding, and wherein decoding the prefix of the truncated binary code comprises parsing the prefix of the truncated binary code from the encoded bitstream.

13. A device for processing video data, the device comprising:
a memory configured to store a block of the video data; and
a video coder in communication with the memory, the video coder being configured to:
determine that the block stored in the memory is a palette-coded block of the video data;
determine a palette for the palette-coded block of the video data, the palette including one or more palette entries, each respective palette entry representing a respective palette index;
determine, based on a total number of indices represented by the palette entries of the palette determined for the palette-coded block, an input parameter for a truncated binary code that includes a prefix and a suffix, wherein the suffix of the truncated binary code represents the respective palette index for a pixel of the palette-coded block of the video data;
code the prefix of the truncated binary code; and
select between a first palette coding mode and a second palette coding mode based only on the prefix of the truncated binary code to determine a palette coding mode with which to code the pixel of the palette-coded block.

14. The device of claim 13 , wherein to code the prefix, the video coder is configured to determine that the prefix has all bins set equal to zero, and wherein to select between the first palette coding mode and the second palette coding mode, the video coder is configured to select the first palette coding mode based on the prefix having all bins equal to zero.

15. The device of claim 14 , wherein the first palette coding mode is an escape palette coding mode, and wherein the video coder is further configured to code a pixel value for the pixel based on the suffix of the truncated binary code.

16. The device of claim 15 , wherein to code the pixel value, the video coder is configured to code the suffix after coding the prefix to determine the palette coding mode with which to code the pixel.

17. The device of claim 13 , wherein to select between the first palette coding mode and the second palette coding mode, the video coder is configured to select the second palette coding mode, and wherein the video coder is further configured to code data positioned between the prefix and the suffix of the truncated binary code to code data that indicates a run length of subsequent pixels to be coded with the pixel.

18. The device of claim 17 , wherein to code the data that indicates the run length, the video coder is configured to code the data that indicates the run length after coding the prefix of the truncated binary code, and wherein the video coder is further configured to code the suffix of the truncated binary code after coding the data that indicates the run length.

19. The device of claim 17 , wherein the video coder is configured to select the second palette coding mode, and wherein the video coder is further configured to code the suffix of the truncated binary code in parallel with coding the data that indicates the run length.

20. The device of claim 13 , wherein to determine the input parameter for the truncated binary code based on the total number of indices represented by the palette entries of the palette, the video coder is configured to determine the input parameter for the truncated binary code based only on the total number of indices represented by the palette entries of the palette.

21. The device of claim 20 , wherein to determine the input parameter for the truncated binary code based only on the total number of indices re

Assignees

• Qualcomm Inc

Inventors

• Pu Wei
• Sole Rojals Joel
• Karczewicz Marta
• Joshi Rajan Laxman
• Hsieh Cheng-Teh
• Seregin Vadim

Classifications

• H04N19/91

  Entropy coding, e.g. variable length coding [VLC] or arithmetic coding · CPC title

• H04N19/182

  the unit being a pixel · CPC title

• H04N19/103

  Selection of coding mode or of prediction mode · CPC title

• H04N19/157

  Assigned coding mode, i.e. the coding mode being predefined or preselected to be further used for selection of another element or parameter · CPC title

• H04N19/176

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