Playlists from multiple tracks (#72)

* Enable playlists based on multiple songs

This commit introduces functionality for generating playlist based on a
set of songs.

For good performance, I also introduce a new distance measure, extended
isolation distance.

While the previous distance metrics, euclidean distance and cosine
distance, could be made to measure distance to a set of songs, the
performance will not be as good.

* Remove *_by_key family of functions

Remove code duplication by making these functions generic over
AsRef<Song> instead of having separate versions.

* Get rid of circular dependency between playlist and song

The playlist module depends on the song module, which in turn depends on
the playlist module. This is confusing, and in this case also completely
unecessary.

* Unify distance metrics

Allow euclidean distance and cosine distance to handle a set of songs as
input. In doing so, we can also remove the ability to generate playlists
from a single song, as that is just a special case of generating a
playlist from many songs anyway.

* Review comment: Improve documentation for single song use case

* Add test for ForestOption as DistanceMetricBuilder.

* Remove unecessary double-reference

* Add missing test assertion.

* Remove comment that is no longer relevant.

* Fix extended isolation forest test case

* Document suggestions and limitations for distance metric

* cargo fmt

CHANGELOG.md

@@ -1,4 +1,11 @@
-#Changelog
+# Changelog
+
+## bliss 0.7.0
+* Add the possibility to make playlists based on multiple songs using extended
+  isolation forest (Thanks @SimonTeixidor!)
+* Remove *_by_key family of functions (Thanks @SimonTeixidor!)
+* Remove circular dependency between playlist and song by removing distances
+  from the `Song` struct (Thanks @SimonTeixidor!)
 
 ## bliss 0.6.11
 * Bump rust-ffmpeg to 6.1.1 to fix build for raspberry pis.

Cargo.toml

@@ -34,7 +34,7 @@ library = [
     "dep:anyhow", "dep:serde_ini", "dep:serde_json",
     "dep:indicatif",
 ]
-serde = ["dep:serde"]
+serde = ["dep:serde", "extended-isolation-forest/serde"]
 
 [dependencies]
 # Until https://github.com/aubio/aubio/issues/336 is somehow solved
@@ -54,6 +54,7 @@ thiserror = "1.0.40"
 strum = "0.24.1"
 strum_macros = "0.24.3"
 rcue = "0.1.3"
+extended-isolation-forest = { version = "0.2.3", default-features = false }
 
 # Deps for the library feature
 serde = { version = "1.0", optional = true, features = ["derive"] }

examples/distance.rs

@@ -1,4 +1,4 @@
-use bliss_audio::Song;
+use bliss_audio::{playlist::euclidean_distance, Song};
 use std::env;
 
 /**
@@ -20,7 +20,7 @@ fn main() -> Result<(), String> {
         "d({:?}, {:?}) = {}",
         song1.path,
         song2.path,
-        song1.distance(&song2)
+        euclidean_distance(&song1.analysis.as_arr1(), &song2.analysis.as_arr1())
     );
     Ok(())
 }

examples/library.rs

@@ -190,7 +190,7 @@ fn main() -> Result<()> {
             .unwrap_or("20")
             .parse::<usize>()?;
         let library: Library<Config> = Library::from_config_path(config_path)?;
-        let songs = library.playlist_from::<()>(song_path, playlist_length)?;
+        let songs = library.playlist_from::<()>(&[song_path], playlist_length)?;
         let song_paths = songs
             .into_iter()
             .map(|s| s.bliss_song.path.to_string_lossy().to_string())

examples/library_extra_info.rs

@@ -208,7 +208,7 @@ fn main() -> Result<()> {
             .unwrap_or("20")
             .parse::<usize>()?;
         let library: Library<Config> = Library::from_config_path(config_path)?;
-        let songs = library.playlist_from::<ExtraInfo>(song_path, playlist_length)?;
+        let songs = library.playlist_from::<ExtraInfo>(&[song_path], playlist_length)?;
         let playlist = songs
             .into_iter()
             .map(|s| {

examples/playlist.rs

@@ -1,5 +1,5 @@
 use anyhow::Result;
-use bliss_audio::playlist::{closest_to_first_song, dedup_playlist, euclidean_distance};
+use bliss_audio::playlist::{closest_to_songs, dedup_playlist, euclidean_distance};
 use bliss_audio::{analyze_paths, Song};
 use clap::{App, Arg};
 use glob::glob;
@@ -77,7 +77,7 @@ fn main() -> Result<()> {
         .into_iter()
         .filter(|x| x == &first_song || paths.contains(&x.path.to_string_lossy().to_string()))
         .collect();
-    closest_to_first_song(&first_song, &mut songs_to_chose_from, euclidean_distance);
+    closest_to_songs(&[first_song], &mut songs_to_chose_from, &euclidean_distance);
     dedup_playlist(&mut songs_to_chose_from, None);
 
     fs::write(analysis_path, serialized)?;

src/lib.rs

@@ -27,13 +27,16 @@
 //!
 //! ### Analyze & compute the distance between two songs
 //! ```no_run
-//! use bliss_audio::{BlissResult, Song};
+//! use bliss_audio::{BlissResult, Song, playlist::euclidean_distance};
 //!
 //! fn main() -> BlissResult<()> {
 //!     let song1 = Song::from_path("/path/to/song1")?;
 //!     let song2 = Song::from_path("/path/to/song2")?;
 //!
-//!     println!("Distance between song1 and song2 is {}", song1.distance(&song2));
+//!     println!(
+//!         "Distance between song1 and song2 is {}",
+//!         euclidean_distance(&song1.analysis.as_arr1(), &song2.analysis.as_arr1())
+//!     );
 //!     Ok(())
 //! }
 //! ```
@@ -42,7 +45,7 @@
 //! ```no_run
 //! use bliss_audio::{
 //!     analyze_paths,
-//!     playlist::{closest_to_first_song, euclidean_distance},
+//!     playlist::{closest_to_songs, euclidean_distance},
 //!     BlissResult, Song,
 //! };
 //!
@@ -53,7 +56,7 @@
 //!     // Assuming there is a first song
 //!     let first_song = songs.first().unwrap().to_owned();
 //!
-//!     closest_to_first_song(&first_song, &mut songs, euclidean_distance);
+//!     closest_to_songs(&[first_song], &mut songs, &euclidean_distance);
 //!
 //!     println!("Playlist is:");
 //!     for song in songs {