NAL unit header
Disclosed are techniques for scalable, multiview, and multiple descriptive video coding using an improved Network Adaptation Layer (NAL) unit header. A NAL unit header can include a layer-id that can be a reference into a table of layer descriptions, which specify the properties of the layer. The improved NAL unit header can further include fields for reference picture management and to identify temporal layers.
1. A method for video decoding, comprising:
receiving a Dependency Parameter Set (DPS) pertaining to a coded video sequence in a layered format and comprising a plurality of layer descriptions, each identified by a first layer_id_and including at least one property of the layer;
receiving a Network Adaptation Layer (NAL) unit header comprising a second layer_id and a temporal id;
identifying one of the plurality of layer descriptions of the DPS by matching the second layer_id with the first layer_id; and
determining at least one property of the layer that the NAL unit belongs to from the identified one of the plurality of layer descriptions;
wherein the DPS includes a dependency parameter set id, the dependency parameter set id being referred to from a slice header;
wherein the DPS is activated once in the coded video sequence and pertains to all pictures of the coded video sequence;
wherein the NAL unit header does not include the at least one property; and
wherein the at least one property comprises at least one of: a dependency id, a quality id, a view id, a depth map flag, and a dependent flag.
2. The method of claim 1 , wherein the temporal_id identifies a temporal sub-layer of a layer identified by the layer_id.
3. The method of claim 1 , wherein the depth_map_flag indicates that the first layer the NAL unit belongs to is a depth map, and is associated with a second layer identified by having the same view_id as the first layer.
4. The method of claim 1 , wherein a predefined value for the second layer_id identifies the presence of extension data.
5. The method of claim 1 , wherein the first layer_id is an indication of a position of the layer in a layer hierarchy.
6. The method of claim 1 , wherein the NAL unit header further comprises at least one of: a store_ref_base_pic_flag and a use_ref_base_pic_flag.
7. The method of claim 1 , wherein the NAL unit header is a slice NAL unit header, and the slice header of the slice carried in the NAL unit comprises at least one of a store_ref_base_pic_flag, and use_ref_base_pic_flag.
8. A method for video encoding, comprising:
determining a layer structure comprising at least one layer having a first layer_id;
encoding a Dependency Parameter Set (DPS) pertaining to a coded video sequence in a layered format, the DPS including a representation of the layer structure and a plurality of layer descriptions comprising at least one property of the layer; and
encoding at least one Network Adaptation Layer (NAL) unit comprising an NAL unit header, the NAL unit header comprising a second layer_id and a temporal id;
wherein the second layer_id is the same as the first layer_id;
wherein the NAL unit header does not include the at least one property;
wherein the DPS includes a dependency parameter set id, the dependency parameter set id being referred to from a slice header;
wherein the DPS is activated once in the coded video sequence and pertains to all pictures of the coded video sequence; and
wherein the at least one property comprises at least one of: a dependency id, a quality id, a view id, a depth map flag, and a dependent flag.
9. The method of claim 8 , wherein the temporal_id identifies a temporal sub-layer of a layer identified by the layer_id.
10. The method of claim 8 , wherein the depth_map_flag indicates that the first layer the NAL unit belongs to is a depth map, and is associated with a second layer identified by having the same view_id as the first layer.
11. The method of claim 8 , wherein a predefined value for the second layer_id identifies the presence of extension data.
12. The method of claim 8 , wherein the first layer_id is an indication of a position of the layer in a layer hierarchy.
13. The method of claim 8 , wherein the NAL unit header further comprises at least one of: a store_ref_base_pic_flag and a use_ref_base_pic_flag.
14. The method of claim 8 , wherein the NAL unit header is a slice NAL unit header, and the slice header of the slice carried in the NAL unit comprises at least one of a store_ref_base_pic_flag, and use_ref_base_pic_flag.
15. A method for removing Network Adaptation Layer (NAL) units from a scalable bitstream, comprising:
receiving and decoding a Dependency Parameter Set (DPS) pertaining to a coded video sequence in a layered format and comprising a plurality of layer descriptions, each identified by a first layer_id and including at least one property of the layer;
receiving a slice NAL unit comprising a NAL unit header comprising a second Layer_id and a temporal id;
identifying one of the plurality of layer descriptions of the DPS by matching the second layer_id with the first layer_id; and
removing the slice NAL unit only if the identified one of the plurality of layer descriptions indicates that the NAL unit belongs to a layer to be removed;
wherein the DPS includes a dependency parameter set id, the dependency parameter set id being referred to from a slice header;
wherein the DPS is activated once in the coded video sequence and pertains to all pictures of the coded video sequence;
wherein the NAL unit header does not include the at least one property; and
wherein the at least one property comprises at least one of: a dependency id, a quality id, a view id, a depth map flag, and a dependent flag.
16. The method of claim 15 , wherein, the DPS comprises a plurality of layer descriptions each having a layer_id, wherein no first layer described by a first layer description is depending on a second layer described by a second layer description, and wherein the layer_id of the first layer description is numerically lower than the layer_id of the second layer description.
17. The method of claim 15 , wherein, the DPS comprises a plurality of layer descriptions each having a layer_id, wherein no first layer described by a first layer description is depending on a second layer described by a second layer description, and wherein the layer_id of the first layer description is numerically higher than the layer_id of the second layer description.
18. A non-transitory computer readable medium comprising a set of instructions to direct a processor to perform the method of claim 1 .
19. A non-transitory computer readable medium comprising a set of instructions to direct a processor to perform the method of claim 8 .
20. A non-transitory computer readable medium comprising a set of instructions to direct a processor to perform the method of claim 15 .