If you’ve lost the text-input field (due to ‘paper-input’ having been deprecated), until there is an update released (has the project been abandoned?..it looks like some time since there were last any updates) you can faily simply make the necessary changes yourself to the mini-media-player-bundle.js in ‘config\www\community\mini-media-player’ (and compress this with gzip compression format to create a new mini-media-player-bundle.js.gz, replacing the old one):
Open mini-media-player-bundle.js and change every entry of ‘paper-input’ with ‘ha-textfield’
Once you’ve made and saved the changes, you will need to reload your frontend cache:
This is simple in a browser, just follow your usual broswer cache reset procedure.
For the iOS app, it’s a bit different: Side bar → Settings → Companion App → Debugging → Reset frontend cache (you may need to do a ‘swipe-down’ to reload the page from the Home Aisstant lovelac screen).
In android, again a bit different: go to your android OS settings (the system settings, not in the HA app) → Apps storage → Home Assistant → Clear Cache.
Hope this helps anyone with similar issues!