Hybrid video coding techniques
Disclosed are techniques for encoding and decoding layered video where the non-temporal enhancement layers and their respective temporal enhancement layers, comply with a scalable video coding standard or technology, and the base layer and its respective temporal enhancement layers does not comply with the same scalable video coding standard or technology. A Video Parameter Set that comprises information about the relationship of layers includes a syntax element indicative of the derivation mechanism for a temporal layer associated with a NAL unit coded in a first coding technology, for example HEVC. For one value of the syntax element, the derivation mechanism is to set the temporal layer of the base layer NAL unit to the value coded in the header of the encapsulating NAL unit, which can be an HEVC NAL unit. For another value, the derivation mechanism is to imply the value of temporal base layer for the first NAL unit.
1. A method for decoding a base layer conforming to a second coding technology from a hybrid scalable bitstream, the hybrid scalable bitstream comprising the base layer conforming to the second coding technology and at least one enhancement layer conforming to a first coding technology, wherein the first and second coding technology are not the same, and wherein both first and second coding technologies use Network Abstraction Layer (NAL) units, the method comprising:
extracting at least one second NAL unit conforming to the second coding technology from a first NAL unit of the hybrid bitstream identified by a pre-determined value of a nal_unit_type indicating the NAL unit is an encapsulation NAL unit, and
decoding, in a decoding device compliant with the second coding technology, the at least one second NAL unit,
wherein the second coding technology is identified by a syntax element in a Video Parameter Set (VPS); and
wherein both the first and second coding technology support temporal layers, and the VPS further includes information indicative of a derivation of the temporal layer associated with the second NAL unit from the temporal layer associated with the first NAL unit.
2. The method of claim 1 , wherein the information indicative of the derivation comprises: a flag nuh_temporal_id_derivation_flag indicative of one of: (1) no derivation, in which case the temporal layer of the second NAL unit is the temporal base layer; or (2) derivation, in which case the temporal layer of the second nal unit is equal to the temporal layer of the first NAL unit.
3. The method of claim 2 , wherein the presence of the nuh_temporal_id_derivation_flag is conditioned on the value of the syntax element in the Video Parameter set identifying the second coding technology.
4. A method for encoding a base layer conforming to a second coding technology in a hybrid scalable bitstream, the hybrid scalable bitstream comprising the base layer conforming to the second coding technology and at least one enhancement layer conforming to a first coding technology, wherein the first and second coding technology are not the same, and wherein both first and second coding technologies use Network Abstraction Layer (NAL) units, the method comprising:
encoding, in a base layer encoding device compliant with the second coding technology, the at least one second NAL unit, and
encapsulating at least one second NAL unit conforming to the second coding technology into a first NAL unit of the hybrid bitstream identified by a pre-determined value of a nal_unit_type indicating the NAL unit is an encapsulation NAL unit,
wherein the second coding technology is identified by a syntax element in a Video Parameter Set (VPS); and
wherein both the first and second coding technology support temporal layers, and the VPS further includes information indicative of a derivation of the temporal layer associated with the second NAL unit from the temporal layer associated with the first NAL unit.
5. The method of claim 4 , wherein the information indicative of the derivation comprises: a flag nuh_temporal_id_derivation_flag indicative of one of: (1) no derivation, in which case the temporal layer of the second NAL unit is the temporal base layer; or (2) derivation, in which case the temporal layer of the second nal unit is equal to the temporal layer of the first NAL unit.
6. The method of claim 5 , wherein the presence of the nuh_temporal_id_derivation_flag is conditioned on the value of the syntax element in the Video Parameter set identifying the second coding technology.
7. A system for decoding a base layer conforming to a second coding technology from a hybrid scalable bitstream, the hybrid scalable bitstream comprising the base layer conforming to the second coding technology and at least one enhancement layer conforming to a first coding technology, wherein the first and second coding technology are not the same, and wherein both first and second coding technologies use Network Abstraction Layer (NAL) units, the system comprising:
a decoding device, the decoding device being compliant with the second coding technology and being configured to:
extract at least one second NAL unit conforming to the second coding technology from a first NAL unit of the hybrid bitstream identified by a pre-determined value of a nal_unit_type indicating the NAL unit is an encapsulation NAL unit, and
decode the at least one second NAL unit,
wherein the second coding technology is identified by a syntax element in a Video Parameter Set (VPS); and
wherein both the first and second coding technology support temporal layers, and the VPS further includes information indicative of a derivation of the temporal layer associated with the second NAL unit from the temporal layer associated with the first NAL unit.
8. The system of claim 7 , wherein the information indicative of the derivation comprises: a flag nuh_temporal_id_derivation_flag indicative of one of: (1) no derivation, in which case the temporal layer of the second NAL unit is the temporal base layer; or (2) derivation, in which case the temporal layer of the second nal unit is equal to the temporal layer of the first NAL unit.
9. The system of claim 8 , wherein the presence of the nuh_temporal_id_derivation_flag is conditioned on the value of the syntax element in the Video Parameter set identifying the second coding technology.
10. A system for encoding a base layer conforming to a second coding technology in a hybrid scalable bitstream, the hybrid scalable bitstream comprising the base layer conforming to the second coding technology and at least one enhancement layer conforming to a first coding technology, wherein the first and second coding technology are not the same, and wherein both first and second coding technologies use Network Abstraction Layer (NAL) units, the system comprising:
an encoding device, the encoding device being configured to:
encode, in a base layer encoding device compliant with the second coding technology, the at least one second NAL unit, and
encapsulate at least one second NAL unit conforming to the second coding technology into a first NAL unit of the hybrid bitstream identified by a pre-determined value of a nal_unit_type indicating the NAL unit is an encapsulation NAL unit,
wherein the second coding technology is identified by a syntax element in a Video Parameter Set (VPS); and
wherein both the first and second coding technology support temporal layers, and the VPS further includes information indicative of a derivation of the temporal layer associated with the second NAL unit from the temporal layer associated with the first NAL unit.
11. The system of claim 10 , wherein the information indicative of the derivation comprises: a flag nuh_temporal_id_derivation_flag indicative of one of: (1) no derivation, in which case the temporal layer of the second NAL unit is the temporal base layer; or (2) derivation, in which case the temporal layer of the second nal unit is equal to the temporal layer of the first NAL unit.
12. The system of claim 11 , wherein the presence of the nuh_temporal_id_derivation_flag is conditioned on the value of the syntax element in the Video Parameter set identifying the second coding technology.
13. A non-transitory computer readable medium comprising a set of executable instructions to direct a processor to perform the method in one of claims 1 to 6 .