Struct NoiseReductionConfig 

pub struct NoiseReductionConfig {
    pub sample_rate_hz: u32,
    pub window_ms: f32,
    pub hop_ms: f32,
    pub oversubtraction_factor: f32,
    pub spectral_floor: f32,
    pub noise_smoothing: f32,
    pub enable: bool,
}

Configuration for noise reduction via spectral subtraction.

Examples

use speech_prep::preprocessing::NoiseReductionConfig;

// Default: 25ms window, 10ms hop, α=2.0, β=0.02
let config = NoiseReductionConfig::default();

// Aggressive noise removal for noisy environment
let config = NoiseReductionConfig {
    oversubtraction_factor: 2.5,
    spectral_floor: 0.01,
    ..Default::default()
};

Fields

sample_rate_hz: u32

Sample rate in Hz.

Default: 16000 Range: 8000-48000

window_ms: f32

STFT window duration in milliseconds.

Default: 25.0 Range: 10.0-50.0

Effect: Longer windows improve frequency resolution but reduce time resolution. 25ms captures 1-3 pitch periods for typical speech.

hop_ms: f32

STFT hop duration in milliseconds.

Default: 10.0 Range: 5.0-25.0

Effect: Smaller hops increase overlap (smoother reconstruction) but require more computation. 10ms hop = 60% overlap with 25ms window.

oversubtraction_factor: f32

Oversubtraction factor (α).

Default: 2.0 Range: 1.0-3.0

Effect: Multiplier for noise estimate in spectral subtraction.

• Higher: More aggressive noise removal, more artifacts
• Lower: Conservative removal, less SNR gain

spectral_floor: f32

Spectral floor (β) as fraction of noise estimate.

Default: 0.02 (2% of noise estimate) Range: 0.001-0.1

Effect: Minimum magnitude after subtraction to prevent musical noise. Acts as a noise gate.

noise_smoothing: f32

Noise profile smoothing factor (α_noise).

Default: 0.98 Range: 0.9-0.999

Effect: Exponential moving average smoothing for noise profile. Higher values = slower adaptation, more stable estimate.

enable: bool

Enable noise reduction.

Default: true

Effect: When false, audio passes through unmodified (bypass mode).

Implementations

impl NoiseReductionConfig

pub fn validate(&self) -> Result<()>

Validate configuration parameters.

Errors

Returns Error::Configuration if:

• sample_rate_hz not in 8000-48000 Hz
• window_ms not in 10.0-50.0 ms
• hop_ms >= window_ms (overlap required)
• oversubtraction_factor not in 1.0-3.0
• spectral_floor not in 0.001-0.1
• noise_smoothing not in 0.9-0.999

pub fn frame_length(&self) -> usize

Calculate frame length in samples.

pub fn hop_length(&self) -> usize

Calculate hop length in samples.

pub fn fft_size(&self) -> usize

Calculate FFT size (next power of 2 >= frame length).

Trait Implementations

impl Clone for NoiseReductionConfig

fn clone(&self) -> NoiseReductionConfig

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for NoiseReductionConfig

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

Formats the value using the given formatter.

impl Default for NoiseReductionConfig

fn default() -> Self

Returns the “default value” for a type.