Slice base skip mode signaling for multiple layer video coding
Methods and apparatus may be used to signal slice skip mode of a multiple layer scalable coding system. A correlation between the corresponding regions of video signals in multiple layers and inter-layer processing techniques may make it possible to infer a slice or picture in the enhancement layer from the corresponding region in a base layer picture. Accordingly, a video stream may be encoded to indicate that an enhancement layer slice or picture may be skipped.
1. A wireless transmit/receive unit (WTRU) for video encoding comprising:
a processor configured to:
identify an enhancement layer having at least two reference layers associated with a multi-layer video;
determine which reference layer of the at least two reference layers of the enhancement layer has a highest priority based on their respective layer priorities signaled at a sequence level;
determine whether a region of an enhancement layer picture of the enhancement layer is to be skipped and predicted using a reference region of an inter-layer reference picture associated with the enhancement layer picture; and
encode the enhancement layer picture based on the determination, wherein on a condition that the reference region of the associated inter-layer reference picture is to be used to predict the region of the enhancement layer, the region of the enhancement layer picture is skipped during encoding, and a syntax element is included in a bit stream indicating that the region is to be skipped and that the reference region of the associated inter-layer reference picture from the determined reference layer that has the highest priority is to be used to predict the region.
2. The WTRU of claim 1 , wherein the syntax element comprises a binary flag that indicates whether the region is skipped.
3. The WTRU of claim 1 , wherein the inter-layer reference picture is a reconstructed picture of the reference layer of the at least two reference layers that has the highest priority, the reconstructed picture being co-located with an enhancement layer picture.
4. The WTRU of claim 1 , wherein the reference region comprises a region of the inter-layer reference picture that is co-located with the region.
5. The WTRU of claim 1 , wherein the processor is further configured to encode the syntax element into a header of a region in the bit stream.
6. The WTRU of claim 1 , wherein the processor is further configured to encode the syntax element into a parameter set associated with a region in the bit stream.
7. The WTRU of claim 6 , wherein the parameter set comprises an adaptation parameter set.
8. The WTRU of claim 1 , wherein the processor is further configured to predict the region using an upsampled portion of the inter-layer reference picture.
9. The WTRU of claim 1 , wherein the skipped region comprises a slice.
10. A wireless transmit/receive unit (WTRU) for video decoding comprising:
a processor configured to:
recover a syntax element associated with an enhancement layer of a scalable bit stream, the syntax element indicating whether a region of an enhancement layer picture of the enhancement layer was skipped during encoding, wherein the enhancement layer comprises at least two reference layers;
upon recovering the syntax element indicating that the region of the enhancement layer picture was skipped during encoding, determine the reference layer of the at least two reference layers of the enhancement layer that has the highest priority based on layer priorities signaled at a sequence level;
select an inter-layer reference picture associated with the enhancement layer picture from the determined the reference layer;
identify a reference region of the inter-layer reference picture; and
decode the enhancement layer picture by predicting the region of the enhancement layer picture using the identified reference region of the inter-layer reference picture.
11. The WTRU of claim 10 , wherein the highest layer of the at least two reference layers is the reference layer that has the highest priority.
12. The WTRU of claim 10 , wherein the syntax element comprises a binary flag that indicates whether the region is skipped.
13. The WTRU of claim 10 , wherein the processor is configured to recover the syntax element from at least one of a header of a region in the scalable bit stream or a parameter set associated with the region in the scalable bit stream.
14. The WTRU of claim 10 , wherein the inter-layer reference picture comprises a picture of the reference layer that has the highest priority that is co-located with an enhancement layer picture.
15. The WTRU of claim 10 , wherein the reference region comprises a region of the inter-layer reference picture that is co-located with the region.
16. The WTRU of claim 10 , wherein the processor is further configured to predict the region based on an upsampled portion of the inter-layer reference picture.
17. The WTRU of claim 10 , wherein the skipped region comprises a slice.
18. A method for video encoding comprising:
identifying an enhancement layer having at least two reference layers associated with a multi-layer video;
determining which reference layer of the at least two reference layers of the enhancement layer has a highest priority using layer priorities signaled at a sequence level;
determining whether a region of an enhancement layer picture of the enhancement layer is to be skipped and predicted using a reference region of an inter-layer reference picture associated with the enhancement layer picture; and
encoding the enhancement layer picture based on the determination, wherein on a condition that the reference region of the associated inter-layer reference picture is to be used to predict the region of the enhancement layer, the region of the enhancement layer picture is skipped during encoding, and a syntax element is included in a bit stream indicating that the region is to be skipped and that the reference region of the associated inter-layer reference picture from the determined reference layer that has the highest priority is to be used to predict the region.
19. The method of claim 18 , wherein the syntax element comprises a binary flag that indicates whether the region is skipped.
20. The method of claim 18 , wherein the inter-layer reference picture is a reconstructed picture of the reference layer of the at least two reference layers that has the highest priority, the reconstructed picture being co-located with an enhancement layer picture and the reference region comprising a region of the inter-layer reference picture that is co-located with the region.
21. The method of claim 18 , wherein the syntax element is encoded into a header associated with a region in the bit stream.
22. The method of claim 18 , wherein the syntax element is encoded into a parameter set associated with a region of the bit stream.
23. The method of claim 18 , further comprising predicting the skipped region based on an upsampled portion of the inter-layer reference picture.
24. The method of claim 18 , wherein the skipped region comprises a slice.