I tried emms but it generates a huge cache file, doesn't work with media keys

I was trying use emacs for everything so I set up emms for music. It was very cool and had nice cover art thumbnails and so forth. But I had two problems that made me go back to using cmus. First, I couldn't get it to work with my media keys, something that works with cmus automatically upon installing (with emms I used (global-set-key (kbd "<XF86AudioPlay>") 'emms-pause), which did not work. So I'd have to have an emacs frame in focus to play and pause. Second, it generated a cache file with metadata for my music that took very long to load on starting emacs as a client and created a big delay shutting down emacs. It was 350mb whereas the cache file for cmus with the metadata for the same Music library was only 7 mbs. I was using emms with mpv. Does anyone know why it generates such a huge cache file? Thanks.

I also tried the "do everything in emacs" route, but could never get EMMS to fully load my library (~50K tracks). Now I use mpd for music. I love emacs, but sometimes other software is just better for certain use cases.

Do you use one of the Emacs clients for mpd?

I should've been more clear. I tried using EMMS with my mpd library and couldn't get it to load. After running emms-cache-set-from-mpd-all I'd get a message in the echo area about loading the cache, but it would never finish. I tried with just a few directories in my library and that worked fine, but never with my entire library. My emacs-fu wasn't great then (still isn't) so I gave up.

Thanks for your comment. It occurred to me since my post that my first problem with the media keys might have to do with mpv and I did discover that that was easily solved by installing "mpv-mpris" from apt.

It might be the the buffer or cache (I don't remember the exact name) option in mpd.conf that you need to increase. I also tried emms with mpd and like OP said, the media keys were not working anymore and had to focus emacs to control playback. In addition, since emms uses it's own cache the mpd indicator of my windows manager was not updating anymore. Now, I use the built-in mpc mode. It's great and everything work as intended. Edit: max_output_buffer_size

I solved both problems, in case anyone's interested for future reference. I just installed mpv-mpris, which allowed emms to be controlled via the media keys. And then I used a different metadata utility, the alternative mentioned in the manual, tinytag. So I did sudo apt install mpv-mpris; then "pip3 install tinytag"; then I symlinked python3 to python since emms calls 'python" somewhere, and then I ran emms-add-directory-tree and that ran without all the previous error messages and created a normal size cache file (10mb, not 350). So problem solved.