Sub-picture bitstream extraction and reposition
Systems and methods described herein employ a high-level syntax design that supports a sub-picture extraction and reposition process. An input video may be encoded into multiple representations, each representation may be represented as a layer. A layer picture may be partitioned into multiple sub-pictures. Each sub-picture may have its own tile partitioning, resolution, color format and bit depth. Each sub-picture is encoded independently from other sub-pictures of the same layer, but it may be inter-predicted from the corresponding sub-pictures from its dependent layers. Each sub-picture may refer to a sub-picture parameter set where the sub-picture properties such as resolution and coordinate is signaled. Each sub-picture parameter set may refer to a PPS where the resolution of the entire picture is signaled.
1 . A method comprising:
encoding in a bitstream a video including at least one picture comprising a plurality of sub-pictures, at least one of the sub-pictures being a layered sub-picture encoded using a plurality of layers, each sub-picture having a respective level and each layer of the layered sub-picture having a respective level; and
signaling in the bitstream a data structure, wherein the data structure indicates the level of each of the plurality of respective sub-pictures, including the level of each respective layer of the layered sub-picture;
wherein the level indicates a predefined set of constraints on values of syntax elements of the respective sub-picture or the respective layer of the layered sub-picture.
2 . The method of claim 1 , further comprising signaling, for each of the sub-pictures, information indicating a tier for the respective sub-picture.
3 . The method of claim 1 , further comprising signaling, for each of the sub-pictures, information indicating a profile for the respective sub-picture.
4 . The method of claim 1 , wherein each of the sub-pictures is associated with a layer, and wherein each sub-picture within a layer is encoded independently from other sub-pictures in the same layer.
5 . An apparatus comprising:
a processor configured to perform at least:
encoding in a bitstream a video comprising a plurality of sub-pictures, at least one of the sub-pictures being a layered sub-picture encoded using a plurality of layers, each sub-picture having a respective level and each layer of the layered sub-picture having a respective level; and
signaling in the bitstream a data structure, wherein the data structure indicates the level of each of the plurality of respective sub-pictures, including the level of each respective layer of the layered sub-picture;
wherein the level indicates a predefined set of constraints on values of syntax elements of the respective sub-picture or the respective layer of the layered sub-picture.
6 . The apparatus of claim 5 , wherein each of the sub-pictures is associated with a layer, and wherein each sub-picture within a layer is encoded independently from other sub-pictures in the same layer.
7 . The apparatus of claim 5 , wherein the processor is further configured to signal at least one output sub-picture set in the bitstream, wherein the output sub-picture set identifies at least a subset of the plurality of sub-pictures and includes the level for each of the sub-pictures in the subset.
8 . The apparatus of claim 5 , wherein the processor is further configured to signal at least one output sub-picture set in the bitstream, wherein the output sub-picture set identifies at least a subset of the plurality of sub-pictures and includes position offset information for each of the sub-pictures in the subset.
9 . A method comprising:
decoding from a bitstream a video including at least one picture comprising a plurality of sub-pictures, at least one of the sub-pictures being a layered sub-picture encoded using a plurality of layers, each sub-picture having a respective level and each layer of the layered sub-picture having a respective level; and
decoding from the bitstream a data structure, wherein the data structure indicates the level of each of the plurality of respective sub-pictures, including the level of each respective layer of the layered sub-picture;
wherein the level indicates a predefined set of constraints on values of syntax elements of the respective sub-picture or the respective layer of the layered sub-picture.
10 . The method of claim 9 , further comprising selecting an output sub-picture set of the sub-pictures based at least in part on the level, wherein decoding the video comprises decoding the selected output sub-picture set.
11 . The method of claim 9 , wherein each of the sub-pictures is associated with a layer, and wherein at least one sub-picture within a layer is decoded independently from other sub-pictures in the same layer.
12 . The method of claim 9 , further comprising composing at least one output frame from the decoded plurality of sub-pictures.
13 . An apparatus comprising:
a processor configured to perform at least:
decoding from a bitstream a video including at least one picture comprising a plurality of sub-pictures, at least one of the sub-pictures being a layered sub-picture encoded using a plurality of layers, each sub-picture having a respective level and each layer of the layered sub-picture having a respective level; and
decoding from the bitstream a data structure, wherein the data structure indicates the level of each of the plurality of respective sub-pictures, including the level of each respective layer of the layered sub-picture;
wherein the level indicates a predefined set of constraints on values of syntax elements of the respective sub-picture or the respective layer of the layered sub-picture.
14 . The apparatus of claim 13 , wherein the processor is further configured to select an output sub-picture set of the sub-pictures based at least in part on the level, and wherein the selected output sub-picture set is decoded.
15 . The apparatus of claim 13 , wherein each of the sub-pictures is associated with a layer, and wherein at least one sub-picture within a layer is decoded independently from other sub-pictures in the same layer.
16 . The apparatus of claim 13 , wherein the processor is further configured to compose at least one output frame from the decoded plurality of sub-pictures.