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 encoding, comprising:
generating a video parameter set (VPS) and a sequence parameter set (SPS), wherein the VPS includes a list of profile tier level (PTL) syntax structures, wherein the list of PTL syntax structures comprises a first PTL syntax structure for a first output layer set (OLS), wherein the first OLS has only one layer, wherein the SPS is referred to by the only one layer and includes a second PTL syntax structure for the first OLS, and wherein the first PTL syntax structure and the second PTL syntax structure are identical; and
encoding the VPS and the SPS into a bitstream.
2 . The method of claim 1 , wherein the only one layer is a lowest layer among layers that refer to the SPS, and wherein the lowest layer is an independent layer.
3 . The method of claim 1 , wherein the list of PTL syntax structures is applied to one or more OLSs specified by the VPS.
4 . The method of claim 1 , wherein the VPS includes an index to the list of PTL syntax structures.
5 . The method of claim 4 , wherein the index is in a range of zero to a value, wherein the value plus 1 specifies a total number of the PTL syntax structures in the VPS.
6 . The method of claim 5 , wherein the value is that of a syntax element in the VPS, and wherein the syntax element is designated vps_num_ptls_minus1.
7 . The method of claim 1 , further comprising extracting a sub-bitstream from the bitstream, wherein the sub-bitstream includes the SPS but does not include the VPS.
8 . The method of claim 7 , further comprising transmitting the sub-bitstream toward a video decoder or storing the sub-bitstream.
9 . The method of claim 1 , further comprising storing the bitstream.
10 . A method of decoding, comprising:
receiving a bitstream comprising a video parameter set (VPS) and a sequence parameter set (SPS), wherein the VPS includes a list of profile tier level (PTL) syntax structures, wherein the list of PTL syntax structures comprises a first PTL syntax structure for a first output layer set (OLS), wherein the first OLS has only one layer, wherein the SPS is referred to by the only one layer and includes a second PTL syntax structure for the first OLS, and wherein the first PTL syntax structure and the second PTL syntax structure are identical; and
decoding the VPS and the SPS from the bitstream.
11 . The method of claim 10 , wherein the only one layer is a lowest layer among layers that refer to the SPS, and wherein the lowest layer is an independent layer.
12 . The method of claim 10 , wherein the list of PTL syntax structures is applied to one or more OLSs specified by the VPS.
13 . The method of claim 10 , wherein the VPS includes an index to the list of PTL syntax structures.
14 . The method of claim 13 , wherein the index is in a range of zero to a value, wherein the value plus 1 specifies a total number of the PTL syntax structures in the VPS.
15 . The method of claim 14 , wherein the value is that of a syntax element in the VPS, and wherein the syntax element is designated vps_num_ptls_minus1.
16 . The method of claim 10 , further comprising extracting a sub-bitstream from the bitstream, wherein the sub-bitstream includes the SPS but does not include the VPS.
17 . A non-transitory computer-readable medium storing an encoded bitstream and one or more instructions that, when executed by at least one processor, cause a decoding device to generate a video based on the encoded bitstream, the encoded bitstream comprising:
a video parameter set (VPS) and a sequence parameter set (SPS), wherein the VPS includes a list of profile tier level (PTL) syntax structures, wherein the list of PTL syntax structures comprises a first PTL syntax structure for a first output layer set (OLS), wherein the first OLS has only one layer, wherein the SPS is referred to by the only one layer and includes a second PTL syntax structure for the first OLS, and wherein the first PTL syntax structure and the second PTL syntax structure are identical.
18 . The non-transitory computer-readable medium of claim 17 , wherein the only one layer is a lowest layer among layers that refer to the SPS, and wherein the lowest layer is an independent layer.
19 . The non-transitory computer-readable medium of claim 17 , wherein the list of PTL syntax structures is applied to one or more OLSs specified by the VPS.
20 . The non-transitory computer-readable medium of claim 17 , wherein the VPS includes an index to the list of PTL syntax structures, wherein the index is in a range of zero to a value, wherein the value plus 1 specifies a total number of the PTL syntax structures in the VPS, and wherein the value is that of a syntax element in the VPS, and wherein the syntax element is designated vps_num_ptls_minus1.