Music Player Daemon

Yes.

(Before you complain: this is an exact and complete answer to your question. If that doesn't satisfy you, ask a different question. Before you do that, read https://www.musicpd.org/help/)

MPD 0.18.9 is more than 5 years old and unsupported. Use the latest version and read https://www.musicpd.org/help/

Your MPD version is very old and unsupported.

Thanks. acmetool ceased working for reasons I don't understand.

Your MPD build has no "curl" (WebDAV) storage plugin. It was disabled at compile time.

You mean run two instances of one MPD installation? Yes, you can do that. Create two configuration files listening on different TCP ports, and pass each configuration file path as command-line argument to MPD.

Yes, you can install MPD on the file server, and let it scan the music on its local hard disk; and then on Android, configure a "proxy" database: https://www.musicpd.org/doc/html/user.html#satellite

This is a upmpdcli bug (it crashes). You should report this bug to the project.

Yes, it is possible. To do this, you must first compile all dependencies as static libraries, and then link MPD with linker flag "-static", e.g. by prepending it as LDFLAGS to the Meson command: LDFFLAGS=-static meson .... None of this is MPD specific. This is true for all programs you wish to link ...

That suggests that it is not a proprietary format. Unlike Vorbis and Opus, it is patent encumbered. See https://en.wikipedia.org/wiki/Advanced_Audio_Coding#Licensing_and_patents There is no free AAC encoder. There is an AAC encoder in FFmpeg, but its license is incompatible with the GPL, thus its u...

Uploaded now.

This is a PolicyKit problem, which has nothing to do with MPD. But you can try to run "ninja install" as root, so privilege elevation through PolicyKit is not necessary.

You're still talking about the crash without describing the crash. That was my very first question, but you keep ignoring it.

There are two memory leaks in your old code and one memory leak in the new code. In both versions, the call to mpd_response_finish() is missing, leaving the connection in an invalid state. And going back to your initial problem: neither version has a mpd_run_delete() call. I'm confused.

Sorry, I havn't gotten around to build and upload it.

Version 2.0.9 of what? libmpdclient? No such version exists. Do you mean version 2.9? I hope not, because that version is more than 5 years old.

The error message "Socket error" was returned by libshout to MPD. I don't know what it means; you may better ask the libshout project for help.