Granted Patent B2

US 9,854,235 · App. 13/777,079 · Granted Dec 26, 2017

Abstract

Claims (39)

1. A method of decoding, in a video decoder, a block of enhancement-layer transform domain data for an encoded video and corresponding to a reconstructed block of reference-layer transform domain data, the method comprising:

for an enhancement-layer element of the block of enhancement-layer transform domain data, wherein the block of enhancement-layer transform domain data is of size W×H, wherein the reconstructed block of reference-layer transform domain data is of size W/R×H/R, and wherein R comprises a non-unity scale factor,

determining whether the enhancement-layer element is located in an upper-left W/R×H/R portion of the block of enhancement-layer transform domain data and,

if the enhancement-layer element is within the upper left W/R×H/R portion, determining a context for that enhancement-layer element based, at least in part, upon a plurality of elements in the reconstructed block of reference-layer transform domain data without upscaling, wherein the plurality of elements are identified by a template that selects the plurality of elements in the reference-layer and wherein the position of the template in the reconstructed block of reference-layer transform domain data is based upon the position of that enhancement-layer element in the block of enhancement-layer transform domain data, and

if the enhancement-layer element is not within the upper left W/R×H/R portion, determining the context for that enhancement-layer element using single-layer contexts;

entropy decoding that enhancement-layer element using its determined context; and

reconstructing and outputting for display a block of image data based on the block of enhancement-layer transform domain data.

2. The method claimed in claim 1 , wherein the template includes an element in the same position in the reconstructed block of reference-layer transform domain data as the position of that enhancement-layer element in the block of enhancement-layer transform domain data.

3. The method claimed in claim 2 , wherein the template further includes two or more elements neighboring the element in the same position.

4. The method claimed in claim 3 , wherein the template includes elements to the right, above, below and to the left of the element in the same position.

5. The method claimed in claim 1 , wherein the template includes elements in a neighborhood defined around a position in the reconstructed block of reference-layer transform domain data corresponding to the position of that enhancement-layer element in the block of enhancement-layer transform domain data.

6. The method claimed in claim 1 , wherein the elements in the reconstructed block of reference-layer transform domain data are the same type of syntax elements as the enhancement-layer element.

7. The method claimed in claim 6 , wherein the enhancement-layer element comprises a significant-coefficient flag, and wherein the elements in the reconstructed block of reference-layer transform domain data comprise a reference-layer significant-coefficient flags.

8. The method claimed in claim 1 , wherein the elements in the reconstructed block of reference-layer transform domain data are a different type of syntax element from the enhancement-layer element.

9. The method claimed in claim 1 , wherein determining context further comprises, for another enhancement-layer element located outside the upper left W/R×H/R portion of the block of enhancement layer transform domain data, determining context based, at least in part, upon the upscaled elements of the reconstructed block of reference-layer transform domain data.

10. A decoder for decoding a block of enhancement-layer transform domain data for an encoded video and corresponding to a reconstructed block of reference-layer transform domain data, the decoder comprising:

a processor;

a memory; and

a decoding application stored in memory and containing instructions for configuring the processor to, for an enhancement-layer element of the block of enhancement-layer transform domain data, wherein the block of enhancement-layer transform domain data is of size W×H, wherein the reconstructed block of reference-layer transform domain data is of size W/R×H/R, and wherein R comprises a non-unity scale factor:

determine whether the enhancement-layer element is located in an upper-left W/R×H/R portion of the block of enhancement-layer transform domain data and,

if the enhancement-layer element is within the upper left W/R×H/R portion, determine a context for that enhancement-layer element based, at least in part, upon a plurality of elements in the reconstructed block of reference-layer transform domain data without upscaling, wherein the plurality of elements are identified by a template that selects the plurality of elements in the reference-layer and wherein the position of the template in the reconstructed block reference-layer of transform domain data is based upon the position of that enhancement-layer element in the block of enhancement-layer transform domain data, and

if the enhancement-layer element is not within the upper left W/R×H/R portion, determine the context for that enhancement-layer element using single-layer contexts;

entropy decode that enhancement-layer element using its determined context; and

reconstruct and output for display a block of image data based on the block of enhancement-layer transform domain data.

11. The decoder claimed in claim 10 , wherein the template includes an element in the same position in the reconstructed block of reference-layer transform domain data as the position of that enhancement-layer element in the block of enhancement-layer transform domain data.

12. The decoder claimed in claim 11 , wherein the template further includes two or more elements neighboring the element in the same position.

13. The decoder claimed in claim 12 , wherein the template includes elements to the right, above, below and to the left of the element in the same position.

14. The decoder claimed in claim 10 , wherein the template includes elements in a neighborhood defined around a position in the reconstructed block of reference-layer transform domain data corresponding to the position of that enhancement-layer element in the block of enhancement-layer transform domain data.

15. The decoder claimed in claim 10 , wherein the elements in the reconstructed block of reference-layer transform domain data are the same type of syntax elements as the enhancement-layer element.

16. The decoder claimed in claim 15 , wherein the enhancement-layer element comprises a significant-coefficient flag, and wherein the elements in the reconstructed block of reference-layer transform domain data comprise a reference-layer significant-coefficient flags.

17. The decoder claimed in claim 10 , wherein the elements in the reconstructed block of reference-layer transform domain data are a different type of syntax element from the enhancement-layer element.

18. The decoder claimed in claim 10 , wherein the processor is further configured to for another enhancement-layer element located outside the upper left W/R×H/R portion of the block of enhancement layer transform domain data, determine context based, at least in part, upon the upscaled elements of the reconstructed block of reference-layer transform domain data.

19. A non-transitory processor-readable medium storing processor-executable instructions which, when executed, cause one or more processors to decode a block of enhancement-layer transform domain data for an encoded video and corresponding to a reconstructed block of reference-layer transform domain data, wherein the instructions, when executed, cause the one or more processors to:

for an enhancement-layer element of the block of enhancement-layer transform domain data, wherein the block of enhancement-layer transform domain data is of size W×H, wherein the reconstructed block of reference-layer transform domain data is of size W/R×H/R, and wherein R comprises a non-unity scale factor,

determine whether the enhancement-layer element is located in an upper-left W/R×H/R portion of the block of enhancement-layer transform domain data and,

if the enhancement-layer element is within the upper left W/R×H/R portion, determine a context for that enhancement-layer element based, at least in part, upon a plurality of elements in the reconstructed block of reference-layer transform domain data without upscaling, wherein the plurality of elements are identified by a template that selects the plurality of elements in the reference-layer and wherein the position of the template in the reconstructed block of reference-layer transform domain data is based upon the position of that enhancement-layer element in the block of enhancement-layer transform domain data, and

if the enhancement-layer element is not within the upper left W/R×H/R portion, determine the context for that enhancement-layer element using single-layer contexts;

entropy decode that enhancement-layer element using its determined context; and

reconstruct and output for display a block of image data based on the block of enhancement-layer transform domain data.

Assignments (6)