Avoidance of redundant signaling in multi-layer video bitstreams
A method of decoding is provided. The method includes receiving a sub-bitstream having a sequence parameter set (SPS) with a profile tier level (PTL) syntax structure for an output layer set (OLS) with only one layer; setting a number of layers in the OLS equal to one based on the OLS having the only one layer; obtaining the PTL syntax structure for the OLS with the only one layer from the SPS when the number of layers in the OLS has been set equal to one; and decoding a picture from the only one layer using the PTL syntax structure to obtain a decoded picture. A corresponding method of encoding is also provided.
1. A method of decoding implemented by a video decoder, comprising:
receiving a sub-bitstream having a profile tier level (PTL) syntax structure and a decoded picture buffer (DPB) syntax structure, wherein when the PTL syntax structure is included in a video parameter set (VPS), one or more output layer sets (OLSs) to which the PTL syntax structure applies are specified by the VPS, and when the PTL syntax structure is included in a sequence parameter set (SPS), the PTL syntax structure applies to an output layer set (OLS) that includes only one layer, and wherein when the DPB syntax structure is included in the VPS, the OLSs to which the DPB syntax structure applies are specified by the VPS, and when the DPB syntax structure is included in the SPS, the DPB syntax structure applies to the OLS that includes only one layer that refers to the SPS;
obtaining the PTL syntax structure for the OLS with the only one layer from the SPS or obtaining the PTL syntax structure for the one or more OLSs from the VPS;
obtaining the DPB syntax structure for the OLS with the only one layer from the SPS or obtaining the DPB syntax structure for the one or more OLSs from the VPS; and
decoding a picture using the PTL syntax structure and the DPB syntax structure to obtain a decoded picture.
2. The method of claim 1 , wherein the PTL syntax structure is designated profile_tier_level( ).
3. The method of claim 1 , wherein the only one layer is the i-th layer, and wherein the OLS with the only one layer is the i-th OLS.
4. The method of claim 1 , wherein the PTL syntax structure is included in the SPS, and wherein the PTL syntax structure is present in an i-th profile_tier_level( ) syntax structure in the SPS.
5. The method of claim 1 , wherein the number of layers in the OLS with the only one layer is a variable designated NumLayersInOls[i].
6. The method of claim 1 , wherein the SPS is referred to by the only one layer.
7. The method of claim 1 , further comprising displaying the decoded picture on a display of an electronic device.
8. A decoding device, comprising:
a receiver configured to receive a sub-bitstream having a profile tier level (PTL) syntax structure and a decoded picture buffer (DPB) syntax structure, wherein when the PTL syntax structure is included in a video parameter set (VPS), one or more output layer sets (OLSs) to which the PTL syntax structure applies are specified by the VPS, and when the PTL syntax structure is included in a sequence parameter set (SPS), the PTL syntax structure applies to an output layer set (OLS) that includes only one layer, and wherein when the DPB syntax structure is included in the VPS, the OLSs to which the DPB syntax structure applies are specified by the VPS, and when the DPB syntax structure is included in the SPS, the DPB syntax structure applies to the OLS that includes only one layer that refers to the SPS; and
one or more processors coupled to the memory, the one or more processors configured to execute the instructions to cause the decoding device to:
obtain the PTL syntax structure for the OLS with the only one layer from the SPS or obtaining the PTL syntax structure for the one or more OLSs from the VPS;
obtain the DPB syntax structure for the OLS with the only one layer from the SPS or obtaining the DPB syntax structure for the one or more OLSs from the VPS; and
decode a picture using the PTL syntax structure and the DPB syntax structure to obtain a decoded picture.
9. The decoding device of claim 8 , wherein the PTL syntax structure is designated profile_tier_level( ), wherein the only one layer is the i-th layer, and wherein the OLS with the only one layer is the i-th OLS.
10. The decoding device of claim 8 , wherein the PTL syntax structure is included in the SPS, and wherein the PTL syntax structure is present in an i-th profile_tier_level( ) syntax structure in the SPS.
11. The decoding device of claim 8 , wherein the number of layers in the OLS with the only one layer is a variable designated NumLayersInOls[i]; and wherein the SPS is referred to by the only one layer.
12. The decoding device of claim 8 , further comprising a display configured to display the decoded picture.