Method and apparatus for slice adaptive motion vector coding for spatial scalable video encoding and decoding

1. A method for spatial scalable video encoding, comprising selecting between scalable coding and non-scalable coding of motion vectors on a slice basis,

wherein said selecting step is performed with respect to at least a first option and a second option,

wherein the motion vectors in both P and B slices are non scalable coded in the first option, and

wherein only the motion vectors in the B slices are non-scalable coded and the motion vectors in the P slices are scalable coded in the second option.

2. The method of claim 1 , wherein said selecting step is performed based on at least one of decoding capabilities of, and decoding criteria utilized for, a target decoder.

3. The method of claim 2 , wherein said selecting step is performed based on a decoder specified scalability fineness level for base layer decoding, when the decoding criteria specifies base layer compliant decoding.

4. The method of claim 2 , wherein said selecting step is performed using a rate-distortion optimization method, when the decoding criteria specifies bitrate scalability.

5. The method of claim 2 , wherein said selecting step is performed such that the motion vectors in B slices are non-scalable coded, when the B-slices are encoded in a base layer and the target decoder is configured to drop the B slices.

6. The method of claim 2 , wherein said selecting step is performed such that the motion vectors for a base layer are scalable coded and the motion vectors for all enhancement layers are non-scalable coded, when more than 2-level spatial scalability is supported by a corresponding encoder for implementing the method.

7. The method of claim 1 , wherein said selecting step is performed with respect to at least the first option and the second option, when encoding criteria include total bitrate coding efficiency and complexity.

8. The method of claim 1 , further comprising adding a syntax field in a slice header to indicate whether a motion vector in a slice is scalable coded or non-scalable coded.

9. A spatial scalable video encoder, comprising an encoder for performing a selection between scalable coding and non-scalable coding of motion vectors on a slice basis,

wherein said encoder performs the selection with respect to at least a first option and a second option,

wherein the motion vectors in both P and B slices are non scalable coded in the first option, and wherein only the motion vectors in the B slices are non-scalable coded and the motion vectors in the P slices are scalable coded in the second option.

10. The spatial scalable video encoder of claim 9 , wherein said encoder performs the selection based on at least one of decoding capabilities of, and decoding criteria utilized for, a target decoder.

11. The spatial scalable video encoder of claim 10 , wherein said encoder performs the selection based on a decoder specified scalability fineness level for base layer decoding, when the decoding criteria specifies base layer compliant decoding.

12. The spatial scalable video encoder of claim 10 , wherein said encoder performs the selection using a rate-distortion optimization method, when the decoding criteria specifies bitrate scalability.

13. The spatial scalable video encoder of claim 10 , wherein said encoder performs the selection such that the motion vectors in B slices are non-scalable coded, when the spatial scalable video encoder codes the B-slices in a base layer and the target decoder is configured to drop the B slices.

14. The spatial scalable video encoder of claim 10 , wherein said encoder performs the selection such that the scalable coding is applied to the motion vectors for a base layer and the non-scalable coding is applied to the motion vectors for all enhancement layers, when more than 2-level spatial scalability is supported by the spatial scalable video encoder.

15. The spatial scalable video encoder of claim 9 , wherein said encoder performs the selection with respect to at least the first option and the second option, when encoding criteria include total bitrate coding efficiency and complexity.

16. The spatial scalable video encoder of claim 9 , wherein said encoder adds a syntax field in a slice header to indicate whether a motion vector in a slice is scalable coded or non-scalable coded.

17. A method for spatial scalable video decoding of a bitstream, comprising:

determining whether to use a motion vector coded in the bitstream or to use a quotient of the motion vector divided by a scaling factor, based on a syntax field in a header of the bitstream;

wherein said determining step is performed with respect to at least a first option and a second option;

wherein the motion vector coded in the bitstream is used for both P and B slices in the first option; and

wherein only the motion vector coded in the bitstream is used for the B slices and the quotient of the motion vector divided by the scaling factor is used for the P slices in the second option.

18. A spatial scalable video decoder for decoding a bitstream, comprising:

a decoder for determining whether to use a motion vector coded in the bitstream or to use a quotient of the motion vector divided by a scaling factor, based on a syntax field in a header of the bitstream;

wherein said decoder performs the selection with respect to at least a first option and a second option;

wherein the motion vector coded in the bitstream is used for both P and B slices in the first option; and

wherein only the motion vector coded in the bitstream is used for the B slices and the quotient of the motion vector divided by the scaling factor is used for the P slices in the second option.