Video coding layer up-switching indication

1 . A method for decoding a set of pictures from a bitstream, the method comprising:

obtaining a step-wise temporal sub-layer access (STSA) indication identifying an STSA picture in an access unit, the access unit comprising an ordered sequence of network abstraction layer (NAL) units, wherein i) the STSA picture has a temporal layer identifier value that identifies a temporal layer and ii) the STSA picture is followed by other pictures in a decoding order;

determining, based on the STSA indication, an STSA position in the bitstream; and

decoding the STSA picture and one or more other pictures following the STSA 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 STSA picture, and c) precedes the STSA position is used for decoding the STSA picture or any other picture that: i) follows the STSA picture in the decoding order and ii) has a temporal layer identifier value that is equal to the temporal layer identifier value of the STSA picture, and

the STSA 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 , 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.

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 a picture parameter set (PPS) type.

4 . The method of claim 1 , wherein obtaining the STSA indication comprises deriving the STSA indication from a video coding layer (VCL) NAL unit type.

5 . The method of claim 1 , wherein the temporal layer identifier value of the STSA picture is not equal to the temporal layer value of the temporal layer to which the STSA picture belongs.

6 . A method for encoding a picture, the method comprising:

encoding a step-wise temporal sub-layer access (STSA) picture, wherein the STSA picture has a temporal layer identifier value that identifies a temporal layer;

encoding an STSA indication that indicates the STSA picture, wherein an STSA position in the bitstream can be identified based on the STSA indication; and

encoding other pictures that follow the STSA 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 STSA picture, and c) precedes the STSA position is used for encoding the STSA picture or any one of the other pictures following the STSA picture in the decoding order that has a temporal layer identifier value that is equal to the temporal layer identifier value of the STSA picture,

the access unit comprises an ordered sequence of network abstraction layer (NAL) units, and

the STSA position is the position of the first NAL unit in the ordered sequence of NAL units.

7 . The method of claim 6 , further comprising the encoder outputting the STSA picture, the STSA indication that identifies the STSA picture, and the other pictures that follow the STSA picture in the decoding order.

8 . The method of claim 6 , 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.

9 . The method of claim 6 , 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.

10 . The method of claim 6 , wherein the temporal layer identifier value of the STSA picture is not equal to the temporal layer value of the temporal layer to which the STSA picture belongs.

11 . 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 step-wise temporal sub-layer access (STSA) indication identifying an STSA picture in an access unit, the access unit comprising an ordered sequence of network abstraction layer (NAL) units, wherein i) the STSA picture has a temporal layer identifier value that identifies a temporal layer and ii) the STSA picture is followed by other pictures in a decoding order;

determining, based on the STSA indication, an STSA position in the bitstream; and

decoding the STSA picture and one or more other pictures following the STSA 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 STSA picture, and c) precedes the STSA position is used for decoding the STSA picture or any other picture that: i) follows the STSA picture in the decoding order and ii) has a temporal layer identifier value that is equal to the temporal layer identifier value of the STSA picture, and

the STSA position is determined to be the position of the first NAL unit in the ordered sequence of NAL units.

12 . 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 step-wise temporal sub-layer access (STSA) picture, wherein the STSA picture has a temporal layer identifier value that identifies a temporal layer;

encoding an STSA indication that indicates the STSA picture, wherein an STSA position in the bitstream can be identified based on the STSA indication; and

encoding other pictures that follow the STSA 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 STSA picture, and c) precedes the STSA position is used for encoding the STSA picture or any one of the other pictures following the STSA picture in the decoding order that has a temporal layer identifier value that is equal to the temporal layer identifier value of the STSA picture,

the access unit comprises an ordered sequence of network abstraction layer (NAL) units, and

the STSA position is the position of the first NAL unit in the ordered sequence of NAL units.

13 . 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 .

14 . 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 6 .