Does dav1d support scalability, such as spatial scalability? Is is possible to decode only 1920x1080 frames from a 3840x2160 video (if the video has been encode

Does dav1d support scalability, such as spatial scalability? Is is possible to decode only 1920x1080 frames from a 3840x2160 video (if the video has been encoded with spatial scalability)? It would be nice to be able to decode smaller frame dimensions with faster decoding time. That would be useful for viewing 4K material on computers which can't decode the full resolution. The same for 10- and 12-bit videos - it would be nice to be able to decode a 8-bit version for 8-bit displays with faster decoding time.