METHODS AND DEVICES FOR INTER-LAYER PREDICTION IN SCALABLE VIDEO COMPRESSION

1 . A method of reconstructing, in a video decoder, an enhancement-layer image based upon a reconstructed reference-layer image using inter-layer prediction, the method comprising:

reconstructing a reference-layer residual and a reference-layer prediction, wherein the reference-layer residual and the reference-layer prediction, when combined, form the reconstructed reference-layer image;

up-sampling the reference-layer residual using a first up-sampling operation;

up-sampling the reference-layer prediction using a second up-sampling operation different from the first up-sampling operation;

generating an inter-layer prediction using the up-sampled reference-layer residual and the up-sampled reference-layer prediction; and

reconstructing the enhancement-layer image based upon the inter-layer prediction.

2 . The method claimed in claim 1 , wherein generating an inter-layer prediction comprises combining the up-sampled reference-layer residual with the up-sampled reference-layer prediction to obtain an up-sampled reconstructed reference-layer image and applying motion compensation to produce the inter-layer prediction.

3 . The method claimed in claim 1 , wherein up-sampling the reference-layer residual using a first up-sampling operation comprises applying a first filter and a second filter to the reference-layer residual, and wherein the second filter comprises an interpolation filter.

4 . The method claimed in claim 3 , up-sampling the reference-layer prediction using a second up-sampling operation comprises applying a third filter and a fourth filter to the reference-layer prediction, and wherein the fourth filter comprises an interpolation filter different from the second filter.

5 . The method claimed in claim 4 , wherein applying the first filter produces integer positions of the up-sampled reference-layer residual, applying the second filter produces fractional positions of the up-sampled reference-layer residual, applying the third filter produces integer positions of the up-sampled reference-layer prediction, and applying the fourth filter produces fractional positions of the up-sampled reference-layer prediction.

6 . The method claimed in claim 3 , wherein the first filter is a 4-tap filter corresponding to the vector [4.5 19 19 −1.5], the second filter is a 3-tap filter corresponding to the vector [2 12 2], the third filter is a 4-tap filter corresponding to the vector [0 19 19 0], and the fourth filter is a 3-tap filter corresponding to the vector [2 12 2].

7 . The method claimed in claim 1 wherein up-sampling the reference-layer residual using a first up-sampling operation comprises applying a first interpolation filter and wherein up-sampling the reference-layer prediction using a second up-sampling operation comprises applying a second interpolation filter different from the first interpolation filter.

8 . The method claimed in claim 7 , further comprising determining the filter parameters for the first interpolation filter and for the second interpolation filter.

9 . A method of reconstructing, in a video decoder, an enhancement-layer image based upon a reconstructed reference-layer image using inter-layer prediction, the method comprising:

reconstructing a reference-layer residual and a reference-layer prediction;

combining the reference-layer residual with the reference-layer prediction to obtain the reconstructed reference-layer image;

up-sampling the reference-layer residual using a first up-sampling operation;

up-sampling the reconstructed reference-layer image using a second up-sampling operation different from the first up-sampling operation;

generating an inter-layer prediction using the up-sampled reconstructed reference-layer image; and

reconstructing the enhancement-layer image based upon the inter-layer prediction and the up-sampled reference-layer residual.

10 . The method claimed in claim 10 , generating an inter-layer prediction comprises applying motion compensation to the up-sampled reference-layer image, and wherein reconstructing the enhancement-layer image includes combining an enhancement-layer residual with the inter-layer prediction and adding the up-sampled reference-layer residual.

11 . A video decoder for decoding a bitstream of scalable-encoded video to reconstruct an enhancement-layer image based on a reconstructed reference-layer image using interlayer prediction, the video decoder comprising:

a processor;

a memory; and

a decoding application stored in memory and containing instructions which, when executed, configure the processor to:

reconstruct a reference-layer residual and a reference-layer prediction, wherein the reference-layer residual and the reference-layer prediction, when combined, form the reconstructed reference-layer image;

up-sample the reference-layer residual using a first up-sampling operation;

up-sample the reference-layer prediction using a second up-sampling operation different from the first up-sampling operation;

generate an inter-layer prediction using the up-sampled reference-layer residual and the up-sampled reference-layer prediction; and

reconstruct the enhancement-layer image based upon the inter-layer prediction.

12 . The video decoder claimed in claim 11 , wherein the processor is configured to generate an inter-layer prediction by combining the up-sampled reference-layer residual with the up-sampled reference-layer prediction to obtain an up-sampled reconstructed reference-layer image and applying motion compensation to produce the inter-layer prediction.

13 . The video decoder claimed in claim 11 , wherein the processor is configured to up-sample the reference-layer residual using a first up-sampling operation by applying a first filter and a second filter to the reference-layer residual, and wherein the second filter comprises an interpolation filter.

14 . The video decoder claimed in claim 13 , wherein the processor is configured to up-sample the reference-layer prediction using a second up-sampling operation by applying a third filter and a fourth filter to the reference-layer prediction, and wherein the fourth filter comprises an interpolation filter different from the second filter.

15 . The video decoder claimed in claim 14 , wherein applying the first filter produces integer positions of the up-sampled reference-layer residual, applying the second filter produces fractional positions of the up-sampled reference-layer residual, applying the third filter produces integer positions of the up-sampled reference-layer prediction, and applying the fourth filter produces fractional positions of the up-sampled reference-layer prediction.

16 . The video decoder claimed in claim 14 , wherein the first filter is a 4-tap filter corresponding to the vector [4.5 19 19 −1.5], the second filter is a 3-tap filter corresponding to the vector [2 12 2], the third filter is a 4-tap filter corresponding to the vector [0 19 19 0], and the fourth filter is a 3-tap filter corresponding to the vector [2 12 2].

17 . The video decoder claimed in claim 11 wherein the processor is configured to up-sample the reference-layer residual using a first up-sampling operation by applying a first interpolation filter, and wherein the processor is configured to up-sample the reference-layer prediction using a second up-sampling operation by applying a second interpolation filter different from the first interpolation filter.

18 . The video decoder claimed in claim 17 , wherein the processor is further configured to determine the filter parameters for the first interpolation filter and for the second interpolation filter.

19 . A video decoder of reconstructing an enhancement-layer image based upon a reconstructed reference-layer image using inter-layer prediction, the video decoder comprising:

memory;

a processor;

a decoding application stored in memory and containing instructions which, when executed, configure the processor to perform the method claimed in claim 9 .

20 . The video decoder claimed in claim 19 , wherein the processor is configured to generate an inter-layer prediction by applying motion compensation to the up-sampled reference-layer image, and wherein the processor is configured to reconstruct the enhancement-layer image by combining an enhancement-layer residual with the inter-layer prediction and adding the up-sampled reference-layer residual.

21 . A non-transitory processor-readable medium storing processor-executable instructions which, when executed, configure one or more processors to perform the method claimed in claim 1 .