Viewing orientation changes in viewport-dependent 360° video streaming are conventionally handled by refreshing the entire 360° coverage with a random-access picture. It is asserted that a viewing orientation change could be handled more efficiently in terms of streaming rate-distortion performance and with less fluctuation in streaming bitrate when only the motion-constrained tile sets (MCTSs) in which the picture quality changes are refreshed with MCTSs from random-access pictures. Thus, the contribution proposes a design goal that the VVC design should enable a way to merge MCTSs originating from a random-access picture and MCTSs originating from a non-random-access picture into the same coded picture without substantial difficulty (e.g., without VLC-level modifications).