[`--autofit=<[W[xH]]>`](https://mpv.io/manual/stable/#options-autofit) It should be "x" not ":" Also [`--autofit-larger=<[W[xH]]>`](https://mpv.io/manual/stable/#options-autofit-larger) seems to work better.
--autofit=<[W[xH]]>It should be "x" not ":"
Also
--autofit-larger=<[W[xH]]>seems to work better.