Video coding layer up-switching indication
There are provided mechanisms for decoding a set of pictures from a bitstream. The method comprises obtaining a layer access, LA, indication identifying an LA picture in an access unit, wherein i) the LA picture has a layer identifier value that identifies a layer and ii) the LA picture is followed by other pictures in a decoding order. The method comprises determining, based on the LA indication, an LA position in the bitstream. The method comprises decoding the LA picture and the other pictures following the LA picture in the decoding order, wherein no parameter set that: a) has a particular type, b) has a layer identifier value equal to the layer identifier value of the LA picture, and c) precedes the LA position is used for decoding the LA picture.
1. A method for decoding a set of pictures from a bitstream, the method comprising:
obtaining a temporal layer access (LA) indication identifying an LA picture in an access unit comprising an ordered sequence of NAL units, wherein i) the LA picture has a temporal layer identifier value that identifies a temporal layer and ii) the LA picture is followed by other pictures in a decoding order;
determining, based on the LA indication, an LA position in the bitstream; and
decoding the LA picture and the other pictures following the LA picture in the decoding order, wherein
no parameter set that: a) has a particular type, b) has a temporal layer identifier value equal to the temporal layer identifier value of the LA picture, and c) precedes the LA position is used for decoding the LA picture or any other picture that i) follows the LA picture in the decoding order and ii) has a temporal layer identifier value that is equal to the temporal layer identifier value of the LA picture, and
the LA position is determined to be the position of the first NAL unit in the ordered sequence of NAL units.
2. The method of claim 1 , where the LA indication is a step-wise temporal sub-layer access (STSA) indication and the LA picture is an STSA picture.
3. The method of claim 1 , wherein the particular type is any type included in a set of one or more particular types, wherein the set of one or more particular types includes an adaptation parameter set (APS) type.
4. The method of claim 1 , wherein the particular type is any type included in a set of one or more particular types, wherein the set of one or more particular types includes a picture parameter set (PPS) type.
5. The method of claim 1 , wherein obtaining the LA indication comprises deriving the LA indication from a VCL NAL unit type.
6. The method of claim 1 , wherein the temporal layer identifier value of the LA picture is not equal to the temporal layer value of the temporal layer to which the LA picture belongs.
7. A method for encoding a picture, the method comprising:
encoding a temporal layer access (LA) picture, wherein the LA picture has a temporal layer identifier value that identifies a temporal layer;
encoding an LA indication that indicates the LA picture such that the LA picture can be identified from the LA indication by a decoder, wherein an LA position in the bitstream can be identified based on the LA indication; and
encoding other pictures that follow the LA picture in a decoding order, wherein
no parameter set that: a) has a particular type, b) has a temporal layer identifier value equal to the temporal layer identifier value of the LA picture, and c) precedes the LA position is used for encoding the LA picture or any one of the other pictures following the LA picture in the decoding order that has a temporal layer identifier value that is equal to the temporal layer identifier value of the LA picture,
the access unit comprises an ordered sequence of NAL units, and
the LA position is the position of the first NAL unit in the ordered sequence of NAL units.
8. The method of claim 7 , further comprising the encoder outputting the LA picture, the LA indication that identifies the LA picture, and the other pictures that follow the LA picture in the decoding order.
9. The method of claim 7 , wherein the particular type is any type included in a set of one or more particular types, wherein the set of one or more particular types includes an adaptation parameter set (APS) type.
10. The method of any one of claim 7 , wherein the particular type is any type included in a set of one or more particular types, wherein the set of one or more particular types includes a picture parameter set (PPS) type.
11. The method of any one of claim 7 , wherein the temporal layer identifier value of the LA picture is not equal to the temporal layer value of the temporal layer to which the LA picture belongs.
12. A video decoder, the video decoder comprising:
memory; and
processing circuitry coupled to the memory, wherein the video decoder is configured to perform a method that comprises:
obtaining a temporal layer access (LA) indication identifying an LA picture in an access unit, wherein i) the LA picture has a temporal layer identifier value that identifies a temporal layer and ii) the LA picture is followed by other pictures in a decoding order;
determining, based on the LA indication, an LA position in the bitstream; and
decoding the LA picture and the other pictures following the LA picture in the decoding order, wherein
no parameter set that: a) has a particular type, b) has a temporal layer identifier value equal to the temporal layer identifier value of the LA picture, and c) precedes the LA position is used for decoding the LA picture or any other picture that i) follows the LA picture in the decoding order and ii) has a temporal layer identifier value that is equal to the temporal layer identifier value of the LA picture,
the access unit comprises an ordered sequence of NAL units, and
the LA position is determined to be the position of the first NAL unit in the ordered sequence of NAL units.
13. A video encoder, the video encoder comprising:
memory; and
processing circuitry coupled to the memory, wherein the video encoder is configured to perform a method that comprises:
encoding a temporal layer access (LA) picture, wherein the LA picture has a temporal layer identifier value that identifies a temporal layer; and
encoding an LA indication that indicates the LA picture such that the LA picture can be identified from the LA indication by a decoder, wherein an LA position in the bitstream can be identified based on the LA indication;
encoding other pictures that follow the LA picture in a decoding order, wherein
no parameter set that: a) has a particular type, b) has a temporal layer identifier value equal to the temporal layer identifier value of the LA picture, and c) precedes the LA position is used for encoding the LA picture or any one of the other pictures following the LA picture in the decoding order that has a temporal layer identifier value that is equal to the temporal layer identifier value of the LA picture,
the access unit comprises an ordered sequence of NAL units, and
the LA position is the position of the first NAL unit in the ordered sequence of NAL units.
14. A non-transitory computer readable medium storing a computer program comprising instructions which when executed by processing circuitry of a decoder causes the decoder to perform the method of claim 1 .
15. A non-transitory computer readable medium storing a computer program comprising instructions which when executed by processing circuitry of an encoder causes the encoder to perform the method of claim 7 .