bliss-rs 0.1.2

A song analysis library for making playlists
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131

#![cfg_attr(feature = "bench", feature(test))]
mod chroma;
pub mod library;
mod misc;
mod song;
mod temporal;
mod timbral;
mod utils;

extern crate crossbeam;
extern crate num_cpus;
use thiserror::Error;

const CHANNELS: u16 = 1;
const SAMPLE_RATE: u32 = 22050;

#[derive(Default, Debug, PartialEq, Clone)]
/// Simple object used to represent a Song, with its path, analysis, and
/// other metadata (artist, genre...)
pub struct Song {
    pub path: String,
    pub artist: String,
    pub title: String,
    pub album: String,
    pub track_number: String,
    pub genre: String,
    /// Vec containing analysis, in order: tempo, zero-crossing rate,
    /// mean spectral centroid, std deviation spectral centroid,
    /// mean spectral rolloff, std deviation spectral rolloff
    /// mean spectral_flatness, std deviation spectral flatness,
    /// mean loudness, std deviation loudness
    /// chroma interval feature 1 to 10
    pub analysis: Vec<f32>,
}

#[derive(Error, Debug, PartialEq)]
pub enum BlissError {
    #[error("Error happened while decoding file – {0}")]
    DecodingError(String),
    #[error("Error happened while analyzing file – {0}")]
    AnalysisError(String),
    #[error("Error happened with the music library provider - {0}")]
    ProviderError(String),
}

/// Simple function to bulk analyze a set of songs represented by their
/// absolute paths.
///
/// When making an extension for an audio player, prefer
/// implementing the `Library` trait.
#[doc(hidden)]
pub fn bulk_analyse(paths: Vec<String>) -> Vec<Result<Song, BlissError>> {
    let mut songs = Vec::with_capacity(paths.len());
    let num_cpus = num_cpus::get();

    crossbeam::scope(|s| {
        let mut handles = Vec::with_capacity(paths.len() / num_cpus);
        let mut chunk_number = paths.len() / num_cpus;
        if chunk_number == 0 {
            chunk_number = paths.len();
        }
        for chunk in paths.chunks(chunk_number) {
            handles.push(s.spawn(move |_| {
                let mut result = Vec::with_capacity(chunk.len());
                for path in chunk {
                    let song = Song::new(&path);
                    result.push(song);
                }
                result
            }));
        }

        for handle in handles {
            songs.extend(handle.join().unwrap());
        }
    })
    .unwrap();

    songs
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_bulk_analyse() {
        let results = bulk_analyse(vec![
            String::from("data/s16_mono_22_5kHz.flac"),
            String::from("data/s16_mono_22_5kHz.flac"),
            String::from("nonexistent"),
            String::from("data/s16_stereo_22_5kHz.flac"),
            String::from("nonexistent"),
            String::from("nonexistent"),
            String::from("nonexistent"),
            String::from("nonexistent"),
            String::from("nonexistent"),
            String::from("nonexistent"),
            String::from("nonexistent"),
        ]);
        let mut errored_songs: Vec<String> = results
            .iter()
            .filter_map(|x| x.as_ref().err().map(|x| x.to_string()))
            .collect();
        errored_songs.sort_by(|a, b| a.cmp(b));

        let mut analysed_songs: Vec<String> = results
            .iter()
            .filter_map(|x| x.as_ref().ok().map(|x| x.path.to_string()))
            .collect();
        analysed_songs.sort_by(|a, b| a.cmp(b));

        assert_eq!(
            vec![
                String::from(
                    "Error happened while decoding file – while opening format: ffmpeg::Error(2: No such file or directory)."
                );
                8
            ],
            errored_songs
        );
        assert_eq!(
            vec![
                String::from("data/s16_mono_22_5kHz.flac"),
                String::from("data/s16_mono_22_5kHz.flac"),
                String::from("data/s16_stereo_22_5kHz.flac"),
            ],
            analysed_songs,
        );
    }
}