Struct DynamicsCore 

pub struct DynamicsCore { /* private fields */ }

Shared dynamics processor used by both compressor and expander, single-band and multiband. Each band in a multiband plugin gets its own DynamicsCore instance.

Implementations

impl DynamicsCore

pub fn new(mode: DynamicsMode, channels: usize, sample_rate: u32) -> Self

Create a new dynamics core processor.

Pre-allocates all Vecs. Initializes coefficients for the given sample rate. LookaheadBuffer is sized for max 20ms capacity.

pub fn initialize(&mut self, sample_rate: u32)

Update sample rate and recompute all derived coefficients.

Resizes level detectors and lookahead buffer for new sample rate.

pub fn reset(&mut self)

Zero all state: envelopes, gate states, hold counters, HPF biquad states, level detectors, lookahead buffer.

pub fn set_attack_release(&mut self, attack_ms: f32, release_ms: f32)

Update attack and release time constants.

Also updates dual release times (slow = release * 4.0).

pub fn set_sidechain_hpf(&mut self, freq_hz: f32, order_index: usize)

Rebuild sidechain HPF biquad cascade using peq_butterworth_highpass().

Same Butterworth cascade pattern as the compressor plugin.

pub fn set_sidechain_tilt(&mut self, tilt_db: f32)

Set a spectral tilt filter on the sidechain detection path.

tilt_db: positive values weight HF more heavily (e.g., +3 dB makes the compressor more sensitive to high frequencies). Negative values weight LF. Implemented as a 1st-order high-shelf at 1 kHz.

pub fn set_sidechain_filter(&mut self, mode: SidechainFilterMode)

Set sidechain filter using the unified enum.

pub fn set_detection_mode(&mut self, mode_index: usize)

Set detection mode: 0=peak, 1=RMS. Reinitializes level detectors.

pub fn set_lookahead_ms(&mut self, ms: f32)

Update the lookahead delay.

pub fn set_program_dependent_release(&mut self, enabled: bool)

Enable or disable program-dependent release (compress mode only).

pub fn set_expand_params( &mut self, hysteresis_db: f32, hold_ms: f32, range_db: f32, )

Set expand-mode parameters: hysteresis, hold, and range.

pub fn mode(&self) -> DynamicsMode

Get the dynamics mode.

pub fn channels(&self) -> usize

Get the number of channels.

pub fn apply_sidechain_filter(&mut self, ch: usize, sample: f32) -> f32

Run the sidechain filter (HPF or Tilt) for this channel.

Returns the filtered sample. If no sidechain filter is active, returns the input sample unchanged.

pub fn detect_level(&mut self, ch: usize, sample: f32) -> f32

Detect level for one sample on a channel.

Peak mode returns abs(sample). RMS mode uses the LevelDetector’s sliding window and returns the linear RMS amplitude.

pub fn calculate_gain_reduction( &self, input_db: f32, threshold: f32, ratio: f32, knee_db: f32, ) -> f32

Calculate gain reduction/expansion attenuation for the given input level.

For Compress mode: standard soft-knee gain reduction (above threshold). For Expand mode: expansion attenuation (below threshold), capped by range_db.

pub fn apply_envelope(&mut self, ch: usize, target_gr: f32) -> f32

Apply one-pole attack/release envelope smoothing.

For compress mode with program_dependent_release enabled, uses DualRelease for the release coefficient. Returns the smoothed gain reduction in dB.

pub fn process_gate_state( &mut self, ch: usize, input_db: f32, threshold: f32, ratio: f32, knee_db: f32, ) -> f32

Process the 3-state gate machine for expansion mode.

Implements Open/Hold/Closing transitions with hysteresis. Returns the target attenuation in dB (0.0 when gate is open, or the expansion attenuation when gate is closing).

This method integrates the gate state machine AND the expansion attenuation calculation, matching the expander plugin’s process_channel pattern.

pub fn envelope_db(&self, ch: usize) -> f32

Get the current envelope value (gain reduction in dB) for a channel.

pub fn measured_makeup_db(&self) -> f32

Get the measured makeup gain in dB.

pub fn measured_makeup_linear(&self) -> f32

Get the measured makeup gain as a linear multiplier.

pub fn update_measured_makeup(&mut self, gain_reduction: f32)

Update the measured makeup tracker with the current gain reduction.

pub fn lookahead_process_frame(&mut self, input: &[f32], output: &mut [f32])

Push one interleaved frame into the lookahead buffer, get the delayed frame out. input and output must have channels elements.

pub fn lookahead_delay_samples(&self) -> usize

Returns the current lookahead delay in samples.

pub fn lookahead_frame_buf(&mut self) -> &mut [f32]

Get a mutable reference to the lookahead frame buffer (pre-allocated).

This buffer has channels elements and is used to avoid per-frame allocation when processing lookahead.

pub fn gate_state(&self, ch: usize) -> GateState

Get the current gate state for a channel (expand mode only).

pub fn range_db(&self) -> f32

Get the range_db value (expand mode only).