aoide

Pronounced /eɪˈiːdiː/ or ay-ee-dee in English.

Aimed at DJs who need to organize and search their music collections.

Quickstart

Populate a database from your local music files and submit search queries.

• Install Rust

• Run the aoide-demo-app:

  cargo run -p aoide-demo-app

The application creates one collection for each selected music directory and sets the title accordingly.

Both the default SQLite database and the application settings can be found in the corresponding config directory of your platform. See the log messages for the file path.

Metadata, tags, and searching

Click on the artwork thumbnail for opening the file URL.

BPM filter

Tracks can be filtered by BPM using +<digits> (greater-or-equal) and -<digits> (less-or-equal).

+80 -120

This filter matches all tracks with a BPM between 80.0 and 120.0 (inclusive).

Hashtag filter

Supports hashtags in the Content Group field, URL-encoded and delimited by whitespace:

#Afterhour #Main%20Floor

The simple search input tokenizer of the app doesn't support spaces in tag labels yet, i.e. prefer #MainFloor instead of #Main%20Floor.

Searching is case-insensitive and for tag labels only the prefix is matched, e.g. searching #main finds #MainFloor.

Search tokens that don't start with # will match various other fields like title, artist, or album.

Multiple genres

Supports multiple genres separated by semicolons as a single field:

Pop;Hip-Hop/Rap;Nu Metal

No multi-valued file tags needed for this purpose.

Features

• Designed for large collections of tracks and playlists
  • 100k and more tracks
• Extended metadata support for DJ applications
  • Multi-valued fields
  • Analysis results and performance data
  • Custom, faceted tags
• Bidirectional synchronization of metadata with file tags
  • MP3/ID3v2, MP4/M4A/ALAC, FLAC, Ogg Vorbis, Opus
  • Mapping (largely) follows MusicBrainz Picard
• Rich filtering and sorting capabilities
  • Query DSL
  • For creating dynamic/smart playlists
• Embedded storage backend
  • Primary: Relational database using SQLite
  • Secondary (optional): Full-text search engine using Tantivy
• Modular architecture
  • Standalone (web) server executables as backend
  • Desktop applications with embedded backend
  • Web apps (WASM)
• Multi-platform
  • Linux/Windows/macOS
  • WASM (partially, only core/-api components)
• Written in pure Rust

Axioms

Globally unique identifiers

All entities in aoide, namely collections, tracks, and playlists are identified by a globally unique UID that is independent of any database backend. We use ULIDs with the default base32 string encoding for this purpose.

Source-centric

Internally metadata is stored and indexed in one or more databases (relational/index). This metadata is imported from media sources, which are considered the actual book of records.

Media sources should primarily carry all the precious information that has been collected and curated over the years. This includes analyzed audio properties like perceived loudness, musical metadata like bpm or key, the position of cue points and loops, as well as any kind of custom metadata.

If the database with the metadata becomes inaccessible, at least the information stored in the audio files should be recoverable.

Backing up only the media sources should preserve as much metadata as possible. This is also helpful when switching from aoide to some other platform or when using different applications in parallel.

Always synchronized

Any modification of external metadata in media sources should be reflected in the database and vice versa. Changes are prioritized according to time stamps, i.e. newer metadata replaces older metadata.

Switching between different applications that modify the metadata of the underlying media sources should work seamlessly. At least when reducing conflicting, non-synchronized modifications to a minimum.

Limitation (temporary)

Export of modified metadata into file tags is implemented, but is untested and has not been enabled yet.

Prepared queries

Traditionally, tracks have been organized into (static) playlists. This feature is also provided by aoide.

That works fine as long as individual tracks are not deleted or replaced. Moreover the contents of these playlists are usually only stored in the database.

A more flexible approach is to dynamically compose playlists through filtering and sorting criteria based on track metadata. This feature is often referred to as smart playlists. If metadata changes, the contents of all smart playlists updates automatically. There is no predefined list of tracks. Only a prepared query that, when executed on demand, returns a list of tracks.

By providing a simple domain-specific language (DSL) for denoting prepared queries applications can manage and organize smart playlists on their own.

Limitations

No (audio) streaming

The service only manages metadata. It is not supposed to provide audio streams for playing the music that is contained in the media sources.

No folder-like organizational structures

Grouping any kind of entities (collections/tracks/playlists) into custom, hierarchical structures like folders is not supported. Client applications are responsible for providing such features as needed. They can leverage stable, globally unique, entity identifiers (UID) for this purpose.

Various file formats (JSON/YAML/TOML/...) are much more suitable for storing hierarchical structures than a (relational) database.

Tested for local files

Currently the focus is on local, file-based storage. The domain model is flexible enough to also include online media sources that could be referenced by arbitrary URIs.

Exemplary use case for testing this ability: Ingest the playlists and corresponding tracks from a user's Spotify account as a separate collection.

Single root directory for relative, local file paths (VFS)

The ability for referencing media sources through a relative path by using a virtual file system (VFS) is restricted to a single, local root directory.

This is probably the most common and flexible use case for local files. By either permanently or temporarily switching the root directory media sources could be accessed and loaded from a different location as long as their relative paths remain unchanged.

Documents

• Build & run the web service
• Contributing

License

License: AGPL-3.0-or-later

This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License along with this program. If not, see https://www.gnu.org/licenses/.