There are disclosed various methods, apparatuses and computer program products for video encoding and decoding. In some embodiments a first coded tile or sub-picture track and a second coded tile or sub-picture track are obtained. The first and second coded tile or sub-picture tracks represent a different spatial part of an input video sequence and have the same width and height in pixels. An indication of a first group of tile or sub-picture tracks that are alternatives for extraction is provided. The first group of tile or sub-picture tracks comprise the first and second coded tile or sub-picture tracks. An extractor track comprising a sample corresponding to a coded picture is created. The sample comprises an extractor, the extractor comprises a sample constructor comprising a reference to the first group of tile or sub-picture tracks. The reference is intended to be resolved by selecting one of the tile or sub-picture tracks in the first group to be a source of extraction, and the sample constructor is intended to be resolved by copying data by reference from the source of extraction.