DMM, the Declarative Music Manager (& Player)

Tired of being dependant on servecies like spotify? Former user of MPD, but hate having to manually collect the audio files? Use NixOS, and want to edit even more configs? Hate YouTube, and want to legally* make them mad?

If any of these things apply to you, you should try DMM!

*I am not a lawyer, but yt-dlp hasn't gotten taken down yet!

Table of Contents

• Explainer/Usage
• Installation
• Getting Started
• Misc

WARNING: the main branch of DMM can move quickly, and the documentation here may be inacurate. the stable branch has the latest stable release, and it is recommended to look there instead

How It Works

DMM, like Nix, is declarative. Using DMM to play music happens in 3 steps

For general configuration see getting started, the default config: /assets/dmm.default.ron and the example config: /examples/dmm.ron

1) Declare

The first step is to define the music that you want to listen to in a config file.

Music Directory: the 'root' directory where DMM's files live. In this there are 3 items

• dmm.ron: This is the main configuration. Here you can create custom keybindings, and change settings
• playlists: This directory contains your playlists, one file per playlist.
• sources: This directory contains 'sources' for music. This is explained more in depth later.

You may want to use git to manage any changes you make to your playlists, but remember to add run/ and cache/ to your .gitignore!

1.1) Playlists

Each playlist is defined with a <playlist-name>.ron file in the playlists/ directory. A playlist file contains the following:

• The name of the playlist
• Imports: any imported sources for the playlist (from the sources/ directory)
• Sources: any non-imported sources for the playlist (declared inline)
• Tracks: Definitions of each track, including which source to use and the input for that source

1.2) Sources

A music player is good, but useless without a way to get the music to play. (cough cough mpd)

Here, DMM provides a rather open-ended solution, implemented through sources. Currently only one exists, which is the Shell source. This source runs a shell command to fetch the audio, allowing for integration with many external programs such as yt-dlp.

Here is an example of using the example yt-dlp source: /examples/sources/yt-dlp.ron to download the song Let It Snow from the link <youtube.com/watch?v=2TA3IKH8Y5c>

Track(
    meta: Meta(
        name: "Let It Snow!",
        artist: "Dean Martin",
    ),
    src: "yt",
    // This is the portion of the youtube link after `watch?v=`
    input: "2TA3IKH8Y5c",
)

2) Fetch

After you have defined a playlist, DMM needs to collect the audio from the sources, and save it in a local cache.

This functionality is currently extremely simple, with a few limitations that will be explained later.

To download the playlist Classic Christmas Songs, navigate to the root of the music directory and run the command

dmm download playlist "Christmas Songs"

the third parameter, (here "Christmas Songs") is used to search all playlist in the playlists/ directory for ones with similar names. it can be a part of, or similar to the playlist name (the program will ask you to check the playlist it chose was correct before continuing)

You can also use the command

dmm download all

To download all playlists in the playlists/ directory

2.1) Updating the Cache

If new songs are added or a source changes, songs need to be re-downloaded. this is as simple as running dmm download again.

• changing a sources name, or the name/artist field of a track will not trigger this
• changing the command/parameters of a source at all will trigger a re-download. there is currently no way to tell dmm to not do this.

2.2) Garbage Collection

When songs are no longer referenced by a playlist, they remain in the cache, taking up space. To clean the cache (delete all audio not currently referenced), run dmm gc

3) Enjoy!

Time to listen to your hard earned music! Navigate to your music directory, and run the following command

dmm player

This opens the player UI, where you can select the playlist and tracks you want to play

And remember piracy, especially from music publishers, is a victimless crime!

3.1) Music Player UI

Navbar (the top of the screen)

• shuffle play (on/off)
• repeat (on/single/off)
• stop/play/pause
• <time in song> -> <length of song>
• <song #>/<# of songs in playlist>
• <track title>

On the left:

• Playlist information
• Track information
• Currently configured keybindings

On the right:

• Track selection: lists track # and title.
• Playlist selection: lists playlist name.
• (by default) they keybindings j and k are used to navigate up and down, h and l are used to change between track and playlist selection, and <return> is used to select the highlighted entry.

Installation

DMM is built on, and for, linux. It may work on windows, but you will need to build from source

Currently no {nixpkgs,AUR} package exists (coming soon?), so installation is only supported through nix flakes, or crates.io.

IMPORTANT: In all examples using Nix, the URL contains a placeholder, <version-name> which must be replaced with one of the following

• stable - will automatically download the latest stable release
• nightly - will get the latest nightly release
• nightly releases will run, but may have bugs / breaking changes / features that break your cache
• nightly releases will not have an associated git tag/release
• main - will download the latest commit
• DO NOT USE: the main branch will often be broken!
• a specific version from the releases tab, eg v<x>.<y>.<z> <- this is not the actual latest release
  • not recommended after 1.0.0: if you choose this method, you need to update the version tag in order to update DMM as well as using nix flake update or similar!

0) From crates.io

not recommended: if you can install through a real package manager, please do

DMM is packaged on crates.io, if you have cargo and the requred dependencies installed, run cargo install dmm

1) NixOS (Flake)

To install the dmm flake, add it to your system configurations inputs

inputs = {
  nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";

  # -- snip --
  
  # -- add this part --
  dmm = {
    url = "tarball+https://git.fawkes.io/mtnash/dmm/archive/<version-name>.tar.gz";
    inputs.nixpkgs.follows = "nixpkgs";
  };
};

Then add the apropreate dmm package to your packages array

packages = with pkgs; [
  inputs.dmm.packages.x86_64-linux.default
  # -- snip --
];

For more information on how to do this, I found this blog post helpful

2) Nix Profile (Flake)

To install dmm non-declaratively using nix profile, run the following:

nix profile install tarball+https://git.fawkes.io/mtnash/dmm/archive/<version-name>.tar.gz

2.1) Nix Build (Flake)

To build, but not install dmm you can use nix build:

nix build tarball+https://git.fawkes.io/mtnash/dmm/archive/<version-name>.tar.gz

The executable will be located in ./result/dmm

3) Build From Source

Dependancies:

• cargo
• rustc nightly
• clang + mold (linux only)
• alsa (linux only)

If all dependancies are built correctly, cargo build --release is all that needs to be done, your binary will end up in target/release/dmm

Getting Started

First, you should have dmm installed and (optionally, but the example playlist uses it) yt-dlp

This guide (and DMM in general) assumes that you have some experience working with the linux command line, If you see any improvements, open an issue/PR!

You should also read the how it works section, this will help you understand how to create new playlists and sources yourself.

Creating a Music Directory

The first step is to decide where to keep your music. You most likely want a directory seperate from the rest of your music (if you have any). This guide will assume you are using ~/music.

After creating the music directory, cd into it and run dmm init. This will create the basic layout of the music directory, as well as a playlist named example. It will also import the example yt-dlp source (/examples/sources/yt-dlp.ron).

Play the Example Playlist

Before you can play the playlist, you have to fetch the tracks from their sources. in ~/music, run dmm download playlist 'example'. the download command will search for that name (it can be incomplete) and download that playlists tracks. you can also use dmm download all to download all playlists at once.

Now that it is downloaded, you can play it. run dmm player to launch the player.

In the center you can see a list of the tracks in the current playlist. You can use j and k to scroll down this list, and enter to play a track.

also see the UI guide for more details.

All of these keybindings and more are listed on the lower left!

Make Your Own!

Take a look at How It Works to see how to create your own playlists, and even sources!

Misc

Use DMM without leaving your ${directory}

To tell DMM to use <path> as the path for your music directory, instead of the current directory, create a .dmm-link.ron file with the following contents

Link(
    music_directory: "<path>"
)