The invention relates to video coding and decoding. A method comprises extracting a first spatial subset from coded pictures of a first bitstream into a second bitstream; extracting a second spatial subset from the coded pictures of the first bitstream into a third bitstream; generating a fourth bitstream by selecting and removing a first set of pictures from the third bitstream, wherein the selection is performed in a manner that the first set of pictures is not required for decoding any pictures of the fourth bitstream; decoding the second bitstream; and decoding the fourth bitstream.