ADVANCED SCREEN CONTENT CODING SOLUTION

• US 20150146976A1
• Filed: 11/20/2014
• Published: 05/28/2015
• Est. Priority Date: 11/22/2013
• Status: Active Application

• Current Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Futurewei Technologies Incorporated (Huawei Investment & Holding Co., Ltd.)
• Inventors: Wang, Wei, Yu, Haoping, Ma, Zhan, Wang, Xian, Ye, Jing
• Granted Patent: US 10,291,827 B2
• Time in Patent Office: Days
• US Class Current: 382/166
• CPC Class Codes: G06T 9/00 Image coding bandwidth or redundancy reduction for static pictures H04N1/41; coding or decoding of static colour picture signals H04N1/64; methods or arrangements for coding, decoding, compressing or decompressing digital video signals H04N19/00
• CPC Class Codes: H04N 1/646 Transmitting or storing colour television type signals, e.g. PAL, Lab; Their conversion into additive or subtractive colour signals or vice versa therefor H04N1/642, H04N1/644 take precedence
• CPC Class Codes: H04N 19/157 Assigned coding mode, i.e. the coding mode being predefined or preselected to be further used for selection of another element or parameter
• CPC 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 19/503 involving temporal prediction adaptive coding with adaptive selection between spatial and temporal predictive coding H04N19/107; adaptive coding with adaptive selection among a plurality of temporal predictive coding modes H04N19/109
• CPC Class Codes: H04N 19/593 involving spatial prediction techniques
• CPC Class Codes: H04N 19/70 characterised by syntax aspects related to video coding, e.g. related to compression standards
• CPC Class Codes: H04N 19/93 Run-length coding
• CPC Class Codes: H04N 2201/0089 Image display device

Abstract

A method and device for coding screen content into a bitstream by selecting a color palette table for a coding unit (CU) of screen content, creating a color index map having indices for the coding unit (CU), and encoding the selected color palette table and the color index map for the CU into a bitstream.

Claims

1. A method for coding screen content into a bitstream, the method comprising:

selecting a color palette table for a coding unit (CU) of screen content;

creating a color index map having indices for the CU using the selected color palette table; and

encoding the selected color palette table and the color index map for the CU into a bitstream.

2. The method as specified in claim 1 wherein the method is processed using a planar color format or an interleaved color format.

3. The method as specified in claim 2 wherein the method is processed at a level selected from the group of:

a CU level, a slice level, a picture level or a sequence level.

4. The method as specified in claim 1 wherein the color palette table is derived from the CU or from a neighboring CU.

5. The method as specified in claim 4 wherein the color palette table is derived from a neighboring CU using a reconstructed CU in a pixel domain.

6. The method as specified in claim 5 further comprising generating a color palette table of the neighboring CU based on available reconstructed pixels, regardless of the CU depth and size.

7. The method as specified in claim 4 further comprising generating a color palette table of the neighboring CU, wherein the neighboring CU is encoded using a color palette mode.

8. The method as specified in claim 4 wherein the neighboring CU is not encoded using a color palette mode, and a neighboring CU color palette table is propagated from a previous CU which is encoded using a color palette mode.

9. The method as specified in claim 1 wherein the color palette table is derived in a pixel domain at a decoder, wherein the encoded bitstream is parsed to reconstruct, for the CU, the color palette table and the color index map.

10. The method as specified in claim 6 wherein a pixel value is derived at each position in the CU by combing the color index, and the color palette table.

11. The method as specified in claim 1 further comprising classifying colors or pixel values of the CU based on a previous derived color palette table for corresponding indices.

12. The method as specified in claim 1 further comprising writing new syntax elements into the encoded bitstream.

13. The method as specified in claim 1 wherein the color palette table is generated and ordered according to a histogram, or its actual color intensity.

14. The method as specified in claim 1 wherein each pixel of the CU is converted into a color index within the color palette table.

15. The method as specified in claim 1 wherein a flag is defined for the CU to indicate whether the CU is processed using a packed fashion or a planar mode.

16. The method as specified in claim 1 wherein the color palette table is processed by encoding a size of the color palette table and each color in the color palette table.

17. The method as specified in claim 1 further comprising generating a flag indicating the CU uses the color palette table form its left or upper CU.

18. The method as specified in claim 1 wherein the index map is encoded using a string match selected from the group comprising:

one dimensional (1-D) string match, a hybrid 1-D string match, and a two dimensional (2-D) string match,

wherein the string match is signaled using matched pairs.

19. The method as specified in claim 17 wherein the string match is performed using a running hash method.

20. The method as specified in claim 1 wherein a two dimensional (2D) search method is performed over the color index map by identifying a location of a current pixel and a reference pixel in the CU as a starting point.

21. The method as specified in claim 1 wherein the CU has a 4:

4;

4 format processed using a down-sampled 4;

2;

0 sampling format.

22. The method as specified in claim 21 wherein the down-sampled format is processed at a level selected from the group of:

a CU level, a slice level, a picture level or a sequence level.

23. A processor for coding screen content into a bitstream, the processor configured to:

select a color palette table for a coding unit (CU) of screen content;

create a color index map having indices for the CU using the selected color palette table; and

encode the selected color palette table and the color index map for the CU into a bitstream.

24. The processor as specified in claim 23 wherein the color palette table is derived from the CU or from a neighboring CU.

25. The method as specified in claim 24 wherein the color palette table is derived from a neighboring CU using a reconstructed CU in a pixel domain.