Struct DecayCurve 

pub struct DecayCurve {
    pub samples: Vec<f64>,
    pub sample_rate: f64,
    pub noise_cutoff_sample: usize,
}

Schroeder backward-integrated decay curve of a RIR, expressed in dB relative to the curve’s peak.

samples[n] = 10·log10( ∫_n^{cutoff} h²(τ) dτ / ∫_0^{cutoff} h²(τ) dτ )

Truncation at cutoff (the estimated noise-floor crossover) avoids the “lift” that a never-decaying integrated noise tail would otherwise add to the curve — see Chu (1978) and Lundeby et al. (1995).

Fields

samples: Vec<f64>

Sample-by-sample Schroeder decay in dB (0 dB at the start, decreasing).

sample_rate: f64

Sample rate the curve was computed at.

noise_cutoff_sample: usize

Index (within samples) at which the underlying RIR was truncated before backward-integration. Below this sample the curve is dominated by noise and should not be used for slope fitting.

Implementations

impl DecayCurve

pub fn from_rir( rir: &[f32], sample_rate: f64, start_sample: usize, noise_cutoff_sample: Option<usize>, ) -> Self

Compute the Schroeder decay curve from a RIR.

start_sample is the index of the direct sound; integration starts from there. noise_cutoff_sample (absolute index in rir) lets the caller override the auto-detected noise truncation; if None, estimate_noise_cutoff is used.

pub fn first_crossing(&self, threshold_db: f64) -> Option<usize>

First sample index at which the curve is ≤ threshold_db. Returns None if the curve never reaches the threshold.

pub fn fit_db_range( &self, upper_db: f64, lower_db: f64, ) -> Option<(f64, f64, f64)>

Least-squares fit of the decay between two dB thresholds.

Returns (slope_db_per_s, intercept_db, r_squared). None if either threshold is never reached or fewer than two samples lie in the band.

Trait Implementations

impl Clone for DecayCurve

fn clone(&self) -> DecayCurve

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for DecayCurve

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

Formats the value using the given formatter.