Method for derivation on sublayer-wise output layer set

1. A method for encoding a video sequence by at least one processor, the method comprising:

determining a value of a temporal sublayer identifier max_tid_il_ref_pics_plus1[i] of a video coding layer (VCL) network abstraction layer (NAL) unit in a video sequence, wherein max_tid_il_ref_pics_plus1[i] is constrained to be less than or equal to a value of vps_max_sublayers_minus1 that specifies a maximum number of temporal sublayers capable of being present in a layer in each coded video sequence referring to a video parameter set (VPS), in the VPS referred to by the VCL NAL unit;

setting the value of max_tid_il_ref_pics_plus1[i] in the video sequence, wherein the value of max_tid_il_ref_pics_plus1[i] being zero specifying that inter-layer prediction is not used by non-intra random access point (IRAP) pictures of an i-th layer; and

encoding the video sequence comprising the value of max_tid_il_ref_pics_plus1[i].

2. The method of claim 1 , wherein a sublayer-wise output layer set is constrained not be derived for independent layers.

3. The method of claim 1 , wherein the value of max_tid_il_ref_pics_plus1[i] being greater than zero specifies that, for decoding pictures of an i-th layer, no picture with a temporal sublayer identifier greater than max_tid_il_ref_pics_plus1[i]−1 is used as an inter-layer reference picture (ILRP).

4. The method of claim 1 , wherein when not present, the value of max_tid_il_ref_pics_plus1[i] is inferred to be equal to vps_max_sublayers_minus1+1.

5. The method of claim 1 , wherein max_tid_il_ref_pics_plus1[i] is constrained to be less than or equal to vps_max_sublayers_minus1+1.

6. The method of claim 1 , wherein a first variable NumSubLayerslnLayerinOLS[i][j] specifies the number of sublayers in a j-th layer output layer in an i-th OLS, wherein a second variable OutputLayerIdInOls[i][j] specifies a nuh layer id value of the j-th output layer in the i-th OLS, wherein a third variable LayerUsedAsOutputLayerFlag[k] specifies whether a k-th layer is used as an output layer in at least one OLS, and wherein the first variable, the second variable, and the third variable are derived from a value of variable max_tid_il_ref_pics_plus1[i].

7. The method of claim 1 , wherein max_tid_il_ref_pics_plus1 and layerIncludedInOlsFlag are constrained not be derived for the independent layers.

8. A device for encoding a video sequence, the device comprising:

at least one memory configured to store program code; and

at least one processor configured to read the program code and operate as instructed by the program code to implement:

determining a value of a temporal sublayer identifier max_tid_il_ref_pics_plus1[i] of a video coding layer (VCL) network abstraction layer (NAL) unit in a video sequence, wherein max_tid_il_ref_pics_plus1[i] is constrained to be less than or equal to a value of vps_max_sublayers_minus1 that specifies a maximum number of temporal sublayers capable of being present in a layer in each coded video sequence referring to a video parameter set (VPS), in the VPS referred to by the VCL NAL unit;

setting the value of max_tid_il_ref_pics_plus1[i] in the video sequence, wherein the value of max_tid_il_ref_pics_plus1[i] being zero specifying that inter-layer prediction is not used by non-intra random access point (IRAP) pictures of an i-th layer; and

encoding the video sequence comprising the value of max_tid_il_ref_pics_plus1[i].

9. The device of claim 8 , wherein a sublayer-wise output layer set is constrained not be derived for independent layers.

10. The device of claim 8 , wherein the value of max_tid_il_ref_pics_plus1[i] being greater than zero specifies that, for decoding pictures of an i-th layer, no picture with a temporal sublayer identifier greater than max_tid_il_ref_pics_plus1[i]−1 is used as an inter-layer reference picture (ILRP).

11. The apparatus of claim 8 , wherein when not present, the value of max_tid_il_ref_pics_plus1[i] is inferred to be equal to vps_max_sublayers_minus1+1.

12. The device of claim 8 , wherein max_tid_il_ref_pics_plus1[i] is constrained to be less than or equal to vps_max_sublayers_minus1+1.

13. The device of claim 8 , wherein a first variable NumSubLayersInLayerInOLS[i][j] specifies the number of sublayers in a j-th layer output layer in an i-th OLS, wherein a second variable OutputLayerIdInOls[i][j] specifies a nuh layer id value of the j-th output layer in the i-th OLS, wherein a third variable LayerUsedAsOutputLayerFlag[k] specifies whether a k-th layer is used as an output layer in at least one OLS, and wherein the first variable, the second variable, and the third variable are derived from a value of variable max_tid_il_ref_pics_plus1[i].

14. The device of claim 8 , wherein max_tid_il_ref_pics_plus1 and layerIncludedInOlsFlag are constrained not be derived for the independent layers.

15. A non-transitory computer-readable medium storing instructions, the instructions comprising: one or more instructions that, when executed by one or more processors of a device for encode a video sequence, cause the one or more processors to:

determine a value of a temporal sublayer identifier max_tid_il_ref_pics_plus1[i] of a video coding layer (VCL) network abstraction layer (NAL) unit in a video sequence, wherein max_tid_il_ref_pics_plus1[i] is constrained to be less than or equal to a value of vps_max_sublayers_minusl that specifies a maximum number of temporal sublayers capable of being present in a layer in each coded video sequence referring to a video parameter set (VPS), in the VPS referred to by the VCL NAL unit;

set the value of max_tid_il_ref_pics_plus1[i] in the video sequence, wherein the value of max_tid_il_ref_pics_plus1[i] being zero specifying that inter-layer prediction is not used by non-intra random access point (IRAP) pictures of an i-th layer; and

encode the video sequence comprising the value of max_tid_il_ref_pics_plus1[i].

16. The non-transitory computer readable medium of claim 15 , wherein a sublayer-wise output layer set is constrained not be derived for independent layers.

17. The non-transitory computer readable medium of claim 15 , wherein the value of max_tid_il_ref_pics_plus1[i] being greater than zero specifies that, for decoding pictures of an i-th layer, no picture with a temporal sublayer identifier greater than max_tid_il_ref_pics_plus1[i]− 1 is used as an inter-layer reference picture (ILRP).

18. The non-transitory computer readable medium of claim 15 , wherein when not present, the value of max_tid_il_ref_pics_plus1[i] is inferred to be equal to vps_max_sublayers_minus1+1.

19. The non-transitory computer readable medium of claim 15 , wherein max_tid_il_ref_pics_plus1[i] is constrained to be less than or equal to vps_max_sublayers_minus1+1.

20. The non-transitory computer readable medium of claim 15 , wherein a first variable NumSubLayersInLayerInOLS[i][j] specifies the number of sublayers in a j-th layer output layer in an i-th OLS, wherein a second variable OutputLayerIdInOls[i][j] specifies a nuh layer id value of the j-th output layer in the i-th OLS, wherein a third variable LayerUsedAsOutputLayerFlag[k] specifies whether a k-th layer is used as an output layer in at least one OLS, and wherein the first variable, the second variable, and the third variable are derived from a value of variable max_tid_il_ref_pics_plus1[ i ].