It seems like the keybinding API in mpv changed in 0.40.0 and python-mpv is not yet compatible with it. There is no new release of python-mpv yet, but it looks like this commit could be applied to fix the issue: https://github.com/jaseg/python-mpv/commit/12850b34bd3b64704f8abd30341a647a73719267 Reproducible: Always See also this jellyfin-mpv-shim issue: https://github.com/jellyfin/jellyfin-mpv-shim/issues/448 And this python-mpv issue: https://github.com/jaseg/python-mpv/issues/297
