A method and related apparatus, the method comprising receiving a bitstream comprising picture data units on one or more scalability layers; determining a first set of layers that are decoded from the bitstream; decoding, from or along the bitstream, a first indication indicative of an end of a coded picture, wherein the first indication is associated with a first layer identifier; decoding, from or along the bitstream, a second indication indicative of a second set of layers that are not present in an access unit; and determining an end of the access unit, when the first layer identifier is the greatest among the first set of layers, or all layers with a layer identifier greater than the first identifier among the first set of layers are included in the second set of layers.