Okay, in accordance with your email I did this. 1. Installed and byte compiled new version of emms-player-mpv.el.
2. Remove my hand setting of the now obsolete variable emms-player-mpv-ipc-method. 3. Removed the legacy --input-ipc-server item from my custom command line parameters in my emms setup. 4. Removed the input-ipc-server item from my mpv config file. And now everything works to perfection. Streams and files play as expected. Volume control works. Seeking works. All without my previous kludges and complications. So much better! Mahalo nui loa for your assistance! -- Bob Newell Honolulu, Hawai`i - Via GNU-Linux/Emacs/Gnus/BBDB