Struct ChromaDesc 

pub struct ChromaDesc { /* private fields */ }

General object holding the chroma descriptor.

Current chroma descriptors are interval features (see https://speech.di.uoa.gr/ICMC-SMC-2014/images/VOL_2/1461.pdf).

Contrary to the other descriptors that can be used with streaming without consequences, this one performs better if the full song is used at once.

Implementations

impl ChromaDesc

pub const WINDOW_SIZE: usize = 8192

pub const MAX_L2_INTERVAL: f32 = 0.25

The theoretical maximum value for IC1-6 is each value at (1/2)². The reason is that extract_interval_features computes the product of the L1-normalized chroma vector (so all of its values are <= 1) by itself. The maximum value of this is all coordinates to 1/2 (since dyads will select three values). The maximum of this is then (1/2)², so the maximum of its L2 norm is this sqrt(2 * (1/2)²) ~= 0.62. However, real-life simulations shown that 0.25 is a good ceiling value (see tests).

pub const MAX_L2_TRIAD: f32 = 0.025

The theoretical maximum value for IC7-10 is each value at (1/3)³. The reason is that extract_interval_features computes the product of the L1-normalized chroma vector (so all of its values are <= 1) by itself. The maximum value of this is all coordinates to 1/3 (since triads will select three values). The maximum of this is then (1/3)³, so the maximum of its L2 norm is this sqrt(4 * (1/3)³) ~= 0.074. However, real-life simulations shown that 0.025 is a good ceiling value (see tests).

pub const MAX_TRIAD_INTERVAL_RATIO: f32 = std::f32::consts::FRAC_PI_2

We are using atan2 to keep the ratio bounded.

pub fn new(sample_rate: u32, n_chroma: u32) -> Self

pub fn do_(&mut self, signal: &[f32]) -> AnalysisResult<()>

Compute and store the chroma of a signal.

Passing a full song here once instead of streaming smaller parts of the song will greatly improve accuracy.

pub fn get_value(&mut self) -> Vec<Feature>

Get the song’s interval features.

Return the 6 pitch class set categories, as well as the major, minor, diminished and augmented triads.

See this paper https://speech.di.uoa.gr/ICMC-SMC-2014/images/VOL_2/1461.pdf for more information (“Timbre-invariant Audio Features for Style Analysis of Classical Music”).

Trait Implementations

impl Clone for ChromaDesc

fn clone(&self) -> ChromaDesc

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ChromaDesc

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.