ADAPTIVE COLOR SPACE TRANSFORM CODING

• US 20170347097A1
• Filed: 08/17/2017
• Published: 11/30/2017
• Est. Priority Date: 05/30/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Tourapis, Alexandros
• Granted Patent: US 10,602,143 B2
• Time in Patent Office: Days
• CPC Class Codes: H04N 19/12 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 Class Codes: H04N 19/136 Incoming video signal characteristics or properties
• CPC Class Codes: H04N 19/17 the unit being an image region, e.g. an object
• CPC Class Codes: H04N 19/186 the unit being a colour or a chrominance component
• CPC Class Codes: H04N 19/625 using discrete cosine transform [DCT]
• CPC Class Codes: H04N 19/70 characterised by syntax aspects related to video coding, e.g. related to compression standards

Abstract

An encoder system may include an analyzer that analyzes a current image area in an input video to select a transform. A selectable residue transformer, controlled by the analyzer, may perform the selectable transform on a residue image generated from the current image area and a predicted current image area, to generate a transformed residue image. An encoder may encode the transformed residue image to generate output data. The analyzer controls the encoder to encode information to identify the selectable transform and to indicate that the selectable transform for the current image area is different from a transform of a previous image area of the input video. A decoder system may include components appropriate for decoding the output data from the encoder system.

Claims

1. A system comprising:

an analyzer that analyzes a current image area in an input video to select a transform;

a selectable residue transformer, controlled by the analyzer, to perform the selectable transform on a residue image generated from the current image area and a predicted current image area, to generate a transformed residue image; and

an encoder that encodes the transformed residue image to generate output data,

wherein the analyzer controls the encoder to encode information to identify the selectable transform and to indicate that the selectable transform for the current image area overrides a transform predicted from a previous image area of the input video.

2. The system of claim 1, wherein the current image area is one of a frame, a slice, and a coding tree unit.

3. The system of claim 1, wherein the encoder comprises an entropy encoder.

4. The system of claim 1, wherein the encoded information identifying the selectable transform specifies coefficients of a selectable inverse transform.

5. The system of claim 1, wherein the encoded information identifying the selectable transform is contained in one of a sequence parameter set, a picture parameter set, and a slice header, preceding encoded residue image data of the current image area.

16. The system of claim 1, wherein the transform is a color transform.

6. A system comprising:

a decoder that receives and decodes input data;

a selectable residue inverse transformer, controlled by the decoder, to perform a selectable inverse transform on the decoded input data, to generate an inverse transformed residue image; and

an integrator that combines the inverse transformed residue image with a predicted image for a current image area to generate a restored current image area of an output video,

wherein the decoder selects the selectable inverse transform based upon encoded information in the input data, the encoded information identifies the selectable inverse transform and indicates that the selectable inverse transform for the current image area overrides a transform predicted from a previous image area of the output video.

7. The system of claim 6, wherein the current image area is one of a frame, a slice, and a coding tree unit.

8. The system of claim 6, wherein the decoder is an entropy decoder.

9. The system of claim 6, wherein the encoded information identifying the selectable inverse transform specifies coefficients of a selectable inverse transform.

10. The system of claim 6, wherein the encoded information identifying the selectable transform is contained in one of a sequence parameter set, a picture parameter set, and a slice header, preceding encoded residue image data of the current image area.

17. The system of claim 6, wherein the selectable inverse transform is a selectable inverse color transform.

11. A method comprising:

receiving and decoding, by a decoder, input data;

performing, by a selectable residue inverse transformer controlled by the decoder, a selectable inverse transform on the decoded input data, to generate an inverse transformed residue image; and

combining, by an integrator, the inverse transformed residue image with a predicted image for a current image area to generate a restored current image area of an output video,

wherein the decoder selects the selectable inverse transform based upon encoded information in the input data, the encoded information identifies the selectable inverse transform and indicates that the selectable inverse transform for the current image area overrides a transform predicted from a previous image area of the output video.

12. The method of claim 11, wherein the current image area is one of a frame, a slice, and a coding tree unit.

13. The method of claim 11, wherein the decoder is an entropy decoder.

14. The method of claim 11, wherein the encoded information identifying the selectable inverse transform specifies coefficients of a selectable inverse transform.

15. The method of claim 11, wherein the encoded information identifying the selectable transform is contained in one of a sequence parameter set, a picture parameter set, and a slice header, preceding encoded residue image data of the current image area.

18. The method of claim 11, wherein the selectable inverse transform is a selectable inverse color transform.