Method for determining predictor blocks for a spatially scalable video codec

1. A method for determining predictor blocks of a first resolution layer image from blocks of a second resolution layer image in video encoding, wherein the method is performed by a spatially scalable video encoder, wherein a resolution of the first resolution layer image is higher than a resolution of the second resolution layer image, the method comprising:

up-scaling each block of the second resolution layer image to a corresponding block of an up-scaled second resolution layer image by using a scale factor different from a ratio of the resolutions of the first resolution layer image and the second resolution layer image;

selecting a block of the up-scaled second resolution layer image among blocks of the up-scaled second resolution layer image surrounding the corresponding block of the up-scaled second resolution layer image as a predictor block of the first resolution layer image and

transmitting a bitstream, wherein the scale factor and vector information for indicating the selected block are carried in the bitstream.

2. The method of claim 1 , wherein the block of the up-scaled second resolution layer image is selected among blocks of the up-scaled second resolution layer image surrounding the corresponding block of the up-scaled second resolution layer image with respect to minimizing a block prediction cost function.

3. The method of claim 1 , further comprising:

determining the scale factor and a displacement vector representing a displacement of the selected block of the up-scaled second resolution layer image with respect to the corresponding block of the up-scaled second resolution layer image for minimizing a block prediction cost function; and

adding the scale factor and the displacement vector to a the bitstream of the video codec.

4. The method of claim 1 , wherein the first resolution layer image comprises a spatial enhancement layer of a H.264/SVC video codec and wherein the second resolution layer image comprises a spatial base layer of the H.264/SVC video codec.

5. A spatially scalable video encoder configured to determine predictor blocks of a first resolution layer image from blocks of a second resolution layer image, wherein a resolution of the first resolution layer image is higher than a resolution of the second resolution layer image, the video encoder comprising:

up-scaling circuitry configured to up-scale each block of the second resolution layer image to a corresponding block of an up-scaled second resolution layer image by using a scale factor different from a ratio of the resolutions of the first resolution layer image and the second resolution layer image;

selection circuitry configured to select a block of the up-scaled second resolution layer image as a predictor block of the first resolution layer image; and

a multiplexer configured to transmit a bitstream, wherein the scale factor and vector information for indicating the selected block are carried in the bitstream.

6. The method of claim 2 , wherein the cost function is based on a distortion (D) created during an encoding process of the video encoder and a bit rate (R) of the bitstream of the video encoder.

7. A method for determining predictor blocks of a first resolution layer image from blocks of a second resolution layer image in video decoding, wherein the method is performed by a spatially scalable video decoder, wherein a resolution of the first resolution layer image is higher than a resolution of the second resolution layer image, the method comprising:

receiving a bitstream, wherein a scale factor and vector infoiiiiation for indicating a selected block are carried in the bitstream;

up-scaling each block of the second resolution layer image to a corresponding block of an up-scaled second resolution layer image by using the scale factor different from a ratio of the resolutions of the first resolution layer image and the second resolution layer image; and

selecting a block of the up-scaled second resolution layer image, based on the vector information, among blocks of the up-scaled second resolution layer image surrounding the corresponding block of the up-scaled second resolution layer image as a predictor block of the first resolution layer image.

8. A spatially scalable video decoder configured to determine predictor blocks of a first resolution layer image from blocks of a second resolution layer image, wherein a resolution of the first resolution layer image is higher than a resolution of the second resolution layer image, the video decoder comprising:

a demultiplexer configured to receive a bitstream, wherein a scale factor and vector information for indicating a selected block are carried in the bitstream;

up-scaling circuitry configured to up-scale each block of the second resolution layer image to a corresponding block of an up-scaled second resolution layer image by using the scale factor different from a ratio of the resolutions of the first resolution layer image and the second resolution layer image; and

selection circuitry configured to select a block of the up-scaled second resolution layer image, based on the vector infoiiiiation, among blocks of the up-scaled second resolution layer image surrounding the corresponding block of the up-scaled second resolution layer image as a predictor block of the first resolution layer image.