Apparatus, a method and a computer program for video coding and decoding

An apparatus for decoding a scalable bitstream comprising a base layer and at least one enhancement layer, the apparatus comprising at least one processor and at least one memory, said at least one memory stored with code thereon, which when executed by said at least one processor, causes the apparatus to perform at least the following:

• receive at least a part of the bitstream and one or more indications in a video parameter set associated with one or more coded video sequences within the bitstream, the video parameter set including parameters that apply to the one or more coded video sequences, and the one or more coded video sequences comprising a sequence of consecutive access units in decoding order from an instantaneous decoding refresh access unit to a next instantaneous decoding refresh access unit, the indications relating to use of picture types and/or network abstraction layer (NAL) unit types of NAL units on said base and one or more enhancement layers for inter-layer prediction;
• determine, on the basis of computational capacity for decoding and/or receiver capabilities and/or network throughput, or being configured to use one or more target output layers for decoding;
• decode from the one or more indications information relating to use of picture types and/or NAL unit types of the NAL units on said base and one or more enhancement layers for inter-layer prediction of the least one enhancement layer from the base layer, wherein the information defines whether the use of inter-layer prediction is restricted to be performed from intra-coded pictures from the base layer;
• determine, based on said information, combinations of picture types and/or NAL unit types and layer identifier values that are not to be decoded to decode the one or more target output layers and/or combinations of picture types and/or NAL unit types and layer identifier values that are to be decoded to decode the one or more target output layers;
• and
• decode the NAL units of the bitstream indicated by the combinations of picture types and/or NAL unit types and layer identifier values to be decoded.