Constraints for inter-layer referencing

1. A video decoding method, comprising:

receiving data from a bitstream carrying data of video pictures in a plurality of different layers, wherein at least one of the plurality of layers comprises temporal sublayers that correspond to levels in a hierarchical temporal prediction structure, each temporal sublayer associated with a temporal identifier;

receiving an inter-layer prediction constraint parameter, the inter-layer prediction constraint parameter indicating a maximum temporal identifier; and

reconstructing a first picture in a first layer by performing inter-layer prediction by referencing one or more coding parameters of an Adaptation Parameter Set (APS) in a second layer, wherein the second layer is among the at least one of the plurality of layers,

wherein the maximum temporal identifier is specific to a combination of the first layer and the second layer, and

wherein the temporal identifier of the temporal sublayer to which the APS belongs satisfies the received inter-layer prediction constraint parameter.

2. The video decoding method of claim 1 , wherein the data of the video pictures are carried in network access level (NAL) units, and wherein the temporal identifier of the referenced data is coded in a header of a NAL unit carrying video content of the APS.

3. The video decoding method of claim 1 , wherein the inter-layer prediction constraint parameter is signaled in a video parameter set (VPS) that is applicable to the first picture when a particular flag in the VPS indicates that the inter-layer prediction constraint parameter is present.

4. The video decoding method of claim 1 , wherein the temporal identifier of the temporal sublayer to which the APS belongs satisfies the received inter-layer prediction constraint parameter when the temporal identifier is less than or equal to the maximum temporal identifier.

5. The video decoding method of claim 1 , further comprising excluding a third picture to be used as reference for inter-layer prediction of the first picture when the third picture is associated with a temporal identifier that is greater than the maximum temporal identifier.

6. The video decoding method of claim 1 , further comprising bypassing inter-layer prediction for the first picture when the inter-layer prediction constraint parameter is set to zero.

7. The video decoding method of claim 1 , wherein the inter-layer prediction constraint parameter is applicable when the second layer is used as a reference layer for inter-layer prediction of the first layer and not applicable when another layer is used as the reference layer for inter-layer prediction of the first layer.

8. The video decoding method of claim 7 , wherein when the inter-layer prediction constraint parameter is set to zero, the second layer is not used as a reference layer for decoding the first layer using inter-layer prediction.

9. The video decoding method of claim 1 , wherein an entry in an inter-layer reference prediction (ILRP) list of the first picture is a reference picture in a reference layer having a temporal identifier that satisfies an inter-layer prediction constraint parameter that is applicable to the first layer and the reference layer.

10. The video decoding method of claim 1 , wherein each entry in an inter-layer reference prediction (ILRP) list of the first picture is either an intra random access point picture (IRAP) or a reference picture in a reference layer having a temporal identifier that satisfies an inter-layer prediction constraint parameter that is applicable to the first layer and the reference layer.

11. A video encoding method, comprising:

receiving video content to be encoded as video pictures in a plurality of different layers into a bitstream, wherein at least one of the plurality of layers comprises temporal sublayers that correspond to levels in a hierarchical temporal prediction structure, each temporal sublayer associated with a temporal identifier;

signaling an inter-layer prediction constraint parameter in the bitstream, the inter-layer prediction constraint parameter indicating a maximum temporal identifier; and

encoding a first picture in a first layer by performing inter-layer prediction by referencing one or more coding parameters of an Adaptation Parameter Set (APS) in a second layer, wherein a temporal identifier of the APS satisfies the inter-layer prediction constraint parameter, and wherein the maximum temporal identifier is specific to a combination of the first layer and the second layer.

12. An electronic apparatus, comprising:

a video decoder circuit configured to perform operations comprising:

receiving data from a bitstream carrying data of video pictures in a plurality of different layers, wherein at least one of the plurality of layers comprises temporal sublayers that correspond to levels in a hierarchical temporal prediction structure, each temporal sublayer associated with a temporal identifier;

receiving an inter-layer prediction constraint parameter, the inter-layer prediction constraint parameter indicating a maximum temporal identifier; and

reconstructing a first picture in a first layer by performing inter-layer prediction by referencing one or more coding parameters of an Adaptation Parameter Set (APS) in a second layer, wherein the second layer is among the at least one of the plurality of layers,

wherein the maximum temporal identifier is specific to a combination of the first layer and the second layer, and

wherein the temporal identifier of the temporal sublayer to which the APS belongs satisfies the received inter-layer prediction constraint parameter.