613 lines
24 KiB
Rust
613 lines
24 KiB
Rust
// Spectral Compressor: an FFT based compressor
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// Copyright (C) 2021-2023 Robbert van der Helm
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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use crossbeam::atomic::AtomicCell;
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use editor::EditorMode;
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use nih_plug::prelude::*;
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use nih_plug_vizia::ViziaState;
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use realfft::num_complex::Complex32;
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use realfft::{ComplexToReal, RealFftPlanner, RealToComplex};
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use std::sync::Arc;
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mod compressor_bank;
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mod dry_wet_mixer;
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mod editor;
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const MIN_WINDOW_ORDER: usize = 6;
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#[allow(dead_code)]
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const MIN_WINDOW_SIZE: usize = 1 << MIN_WINDOW_ORDER; // 64
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const DEFAULT_WINDOW_ORDER: usize = 12;
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#[allow(dead_code)]
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const DEFAULT_WINDOW_SIZE: usize = 1 << DEFAULT_WINDOW_ORDER; // 4096
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const MAX_WINDOW_ORDER: usize = 15;
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const MAX_WINDOW_SIZE: usize = 1 << MAX_WINDOW_ORDER; // 32768
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const MIN_OVERLAP_ORDER: usize = 2;
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#[allow(dead_code)]
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const MIN_OVERLAP_TIMES: usize = 1 << MIN_OVERLAP_ORDER; // 4
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const DEFAULT_OVERLAP_ORDER: usize = 3;
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#[allow(dead_code)]
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const DEFAULT_OVERLAP_TIMES: usize = 1 << DEFAULT_OVERLAP_ORDER; // 4
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const MAX_OVERLAP_ORDER: usize = 5;
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#[allow(dead_code)]
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const MAX_OVERLAP_TIMES: usize = 1 << MAX_OVERLAP_ORDER; // 32
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/// This is a port of <https://github.com/robbert-vdh/spectral-compressor/>.
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pub struct SpectralCompressor {
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params: Arc<SpectralCompressorParams>,
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/// The current buffer config, used for updating the compressors.
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buffer_config: BufferConfig,
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/// An adapter that performs most of the overlap-add algorithm for us.
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stft: util::StftHelper<1>,
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/// Contains a Hann window function of the current window length, passed to the overlap-add
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/// helper. Allocated with a `MAX_WINDOW_SIZE` initial capacity.
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window_function: Vec<f32>,
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/// A mixer to mix the dry signal back into the processed signal with latency compensation.
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dry_wet_mixer: dry_wet_mixer::DryWetMixer,
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/// Spectral per-bin upwards and downwards compressors with soft-knee settings. This is where
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/// the magic happens.
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compressor_bank: compressor_bank::CompressorBank,
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/// The algorithms for the FFT and IFFT operations, for each supported order so we can switch
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/// between them without replanning or allocations. Initialized during `initialize()`.
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plan_for_order: Option<[Plan; MAX_WINDOW_ORDER - MIN_WINDOW_ORDER + 1]>,
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/// The output of our real->complex FFT.
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complex_fft_buffer: Vec<Complex32>,
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}
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/// An FFT plan for a specific window size, all of which will be precomputed during initilaization.
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struct Plan {
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/// The algorithm for the FFT operation.
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r2c_plan: Arc<dyn RealToComplex<f32>>,
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/// The algorithm for the IFFT operation.
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c2r_plan: Arc<dyn ComplexToReal<f32>>,
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}
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#[derive(Params)]
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pub struct SpectralCompressorParams {
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/// The editor state, saved together with the parameter state so the custom scaling can be
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/// restored.
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#[persist = "editor-state"]
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pub editor_state: Arc<ViziaState>,
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/// The mode the editor is currently in. Essentially just a fancy boolean to indicate whether
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/// it's expanded or not.
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#[persist = "editor-mode"]
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pub editor_mode: Arc<AtomicCell<EditorMode>>,
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// NOTE: These `Arc`s are only here temporarily to work around Vizia's Lens requirements so we
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// can use the generic UIs
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/// Global parameters. These could just live in this struct but I wanted a separate generic UI
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/// just for these.
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#[nested(group = "global")]
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pub global: Arc<GlobalParams>,
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/// Parameters controlling the compressor thresholds and curves.
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#[nested(group = "threshold")]
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pub threshold: Arc<compressor_bank::ThresholdParams>,
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/// Parameters for the upwards and downwards compressors.
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#[nested(group = "compressors")]
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pub compressors: compressor_bank::CompressorBankParams,
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}
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/// Global parameters controlling the output stage and all compressors.
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#[derive(Params)]
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pub struct GlobalParams {
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/// Makeup gain applied after the IDFT in the STFT process. If automatic makeup gain is enabled,
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/// then this acts as an offset on top of that. This is stored as linear gain.
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#[id = "output"]
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pub output_gain: FloatParam,
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// TODO: Bring this back, and with values that make more sense
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// /// Try to automatically compensate for gain differences with different input gain, threshold, and ratio values.
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// #[id = "auto_makeup"]
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// auto_makeup_gain: BoolParam,
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/// How much of the dry signal to mix in with the processed signal. The mixing is done after
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/// applying the output gain. In other words, the dry signal is not gained in any way.
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#[id = "dry_wet"]
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pub dry_wet_ratio: FloatParam,
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/// The size of the FFT window as a power of two (to prevent invalid inputs).
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#[id = "stft_window"]
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pub window_size_order: IntParam,
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/// The amount of overlap to use in the overlap-add algorithm as a power of two (again to
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/// prevent invalid inputs).
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#[id = "stft_overlap"]
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pub overlap_times_order: IntParam,
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/// The compressor's attack time in milliseconds. Controls both upwards and downwards
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/// compression.
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#[id = "attack"]
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pub compressor_attack_ms: FloatParam,
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/// The compressor's release time in milliseconds. Controls both upwards and downwards
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/// compression.
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#[id = "release"]
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pub compressor_release_ms: FloatParam,
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}
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impl Default for SpectralCompressor {
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fn default() -> Self {
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// Changing any of the compressor threshold or ratio parameters will set an atomic flag in
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// this object that causes the compressor thresholds and ratios to be recalcualted
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let compressor_bank = compressor_bank::CompressorBank::new(2, MAX_WINDOW_SIZE);
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SpectralCompressor {
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params: Arc::new(SpectralCompressorParams::new(&compressor_bank)),
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buffer_config: BufferConfig {
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sample_rate: 1.0,
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min_buffer_size: None,
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max_buffer_size: 0,
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process_mode: ProcessMode::Realtime,
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},
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// These three will be set to the correct values in the initialize function
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stft: util::StftHelper::new(2, MAX_WINDOW_SIZE, 0),
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window_function: Vec::with_capacity(MAX_WINDOW_SIZE),
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dry_wet_mixer: dry_wet_mixer::DryWetMixer::new(0, 0, 0),
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compressor_bank,
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// This is initialized later since we don't want to do non-trivial computations before
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// the plugin is initialized
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plan_for_order: None,
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complex_fft_buffer: Vec::with_capacity(MAX_WINDOW_SIZE / 2 + 1),
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}
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}
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}
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impl Default for GlobalParams {
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fn default() -> Self {
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GlobalParams {
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// We don't need any smoothing for these parameters as the overlap-add process will
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// already act as a form of smoothing
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output_gain: FloatParam::new(
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"Output Gain",
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util::db_to_gain(0.0),
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FloatRange::Skewed {
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min: util::db_to_gain(-50.0),
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max: util::db_to_gain(50.0),
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factor: FloatRange::gain_skew_factor(-50.0, 50.0),
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},
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)
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.with_unit(" dB")
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.with_value_to_string(formatters::v2s_f32_gain_to_db(2))
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.with_string_to_value(formatters::s2v_f32_gain_to_db()),
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// auto_makeup_gain: BoolParam::new("Auto Makeup Gain", true),
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dry_wet_ratio: FloatParam::new("Mix", 1.0, FloatRange::Linear { min: 0.0, max: 1.0 })
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.with_unit("%")
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.with_smoother(SmoothingStyle::Linear(15.0))
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.with_value_to_string(formatters::v2s_f32_percentage(0))
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.with_string_to_value(formatters::s2v_f32_percentage()),
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window_size_order: IntParam::new(
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"Window Size",
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DEFAULT_WINDOW_ORDER as i32,
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IntRange::Linear {
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min: MIN_WINDOW_ORDER as i32,
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max: MAX_WINDOW_ORDER as i32,
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},
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)
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.with_value_to_string(formatters::v2s_i32_power_of_two())
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.with_string_to_value(formatters::s2v_i32_power_of_two()),
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overlap_times_order: IntParam::new(
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"Window Overlap",
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DEFAULT_OVERLAP_ORDER as i32,
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IntRange::Linear {
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min: MIN_OVERLAP_ORDER as i32,
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max: MAX_OVERLAP_ORDER as i32,
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},
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)
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.with_value_to_string(formatters::v2s_i32_power_of_two())
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.with_string_to_value(formatters::s2v_i32_power_of_two()),
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compressor_attack_ms: FloatParam::new(
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"Attack",
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150.0,
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FloatRange::Skewed {
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min: 0.0,
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max: 10_000.0,
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factor: FloatRange::skew_factor(-2.0),
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},
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)
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.with_unit(" ms")
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.with_step_size(0.1),
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compressor_release_ms: FloatParam::new(
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"Release",
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300.0,
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FloatRange::Skewed {
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min: 0.0,
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max: 10_000.0,
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factor: FloatRange::skew_factor(-2.0),
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},
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)
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.with_unit(" ms")
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.with_step_size(0.1),
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}
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}
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}
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impl SpectralCompressorParams {
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/// Create a new [`SpectralCompressorParams`] object. Changing any of the compressor threshold
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/// or ratio parameters causes the passed compressor bank's parameters to be updated.
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pub fn new(compressor_bank: &compressor_bank::CompressorBank) -> Self {
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let editor_mode: Arc<AtomicCell<EditorMode>> = Arc::default();
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SpectralCompressorParams {
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editor_state: editor::default_state(editor_mode.clone()),
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editor_mode,
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// TODO: Do still enable per-block smoothing for these settings, because why not. This
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// will require updating the compressor bank.
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global: Arc::new(GlobalParams::default()),
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threshold: Arc::new(compressor_bank::ThresholdParams::new(compressor_bank)),
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compressors: compressor_bank::CompressorBankParams::new(compressor_bank),
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}
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}
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}
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impl Plugin for SpectralCompressor {
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const NAME: &'static str = "Spectral Compressor";
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const VENDOR: &'static str = "Robbert van der Helm";
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const URL: &'static str = env!("CARGO_PKG_HOMEPAGE");
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const EMAIL: &'static str = "mail@robbertvanderhelm.nl";
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const VERSION: &'static str = env!("CARGO_PKG_VERSION");
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const AUDIO_IO_LAYOUTS: &'static [AudioIOLayout] = &[
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AudioIOLayout {
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main_input_channels: NonZeroU32::new(2),
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main_output_channels: NonZeroU32::new(2),
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aux_input_ports: &[new_nonzero_u32(2)],
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..AudioIOLayout::const_default()
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},
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AudioIOLayout {
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main_input_channels: NonZeroU32::new(1),
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main_output_channels: NonZeroU32::new(1),
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aux_input_ports: &[new_nonzero_u32(1)],
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..AudioIOLayout::const_default()
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},
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];
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const SAMPLE_ACCURATE_AUTOMATION: bool = true;
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type SysExMessage = ();
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type BackgroundTask = ();
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fn params(&self) -> Arc<dyn Params> {
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self.params.clone()
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}
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fn editor(&self, _async_executor: AsyncExecutor<Self>) -> Option<Box<dyn Editor>> {
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editor::create(self.params.clone(), self.params.editor_state.clone())
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}
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fn initialize(
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&mut self,
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audio_io_layout: &AudioIOLayout,
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buffer_config: &BufferConfig,
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context: &mut impl InitContext<Self>,
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) -> bool {
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// Needed to update the compressors later
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self.buffer_config = *buffer_config;
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// This plugin can accept a variable number of audio channels, so we need to resize
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// channel-dependent data structures accordingly
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let num_output_channels = audio_io_layout
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.main_output_channels
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.expect("Plugin does not have a main output")
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.get() as usize;
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if self.stft.num_channels() != num_output_channels {
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self.stft = util::StftHelper::new(self.stft.num_channels(), MAX_WINDOW_SIZE, 0);
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}
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self.dry_wet_mixer.resize(
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num_output_channels,
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buffer_config.max_buffer_size as usize,
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MAX_WINDOW_SIZE,
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);
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self.compressor_bank
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.update_capacity(num_output_channels, MAX_WINDOW_SIZE);
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// Planning with RustFFT is very fast, but it will still allocate we we'll plan all of the
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// FFTs we might need in advance
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if self.plan_for_order.is_none() {
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let mut planner = RealFftPlanner::new();
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let plan_for_order: Vec<Plan> = (MIN_WINDOW_ORDER..=MAX_WINDOW_ORDER)
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.map(|order| Plan {
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r2c_plan: planner.plan_fft_forward(1 << order),
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c2r_plan: planner.plan_fft_inverse(1 << order),
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})
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.collect();
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self.plan_for_order = Some(
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plan_for_order
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.try_into()
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.unwrap_or_else(|_| panic!("Mismatched plan orders")),
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);
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}
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let window_size = self.window_size();
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self.resize_for_window(window_size);
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context.set_latency_samples(self.stft.latency_samples());
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true
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}
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fn reset(&mut self) {
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self.dry_wet_mixer.reset();
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self.compressor_bank.reset();
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}
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fn process(
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&mut self,
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buffer: &mut Buffer,
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aux: &mut AuxiliaryBuffers,
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context: &mut impl ProcessContext<Self>,
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) -> ProcessStatus {
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// If the window size has changed since the last process call, reset the buffers and chance
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// our latency. All of these buffers already have enough capacity so this won't allocate.
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let window_size = self.window_size();
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let overlap_times = self.overlap_times();
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if self.window_function.len() != window_size {
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self.resize_for_window(window_size);
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context.set_latency_samples(self.stft.latency_samples());
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}
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// These plans have already been made during initialization we can switch between versions
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// without reallocating
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let fft_plan = &mut self.plan_for_order.as_mut().unwrap()
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[self.params.global.window_size_order.value() as usize - MIN_WINDOW_ORDER];
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let num_bins = self.complex_fft_buffer.len();
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// The Hann window function spreads the DC signal out slightly, so we'll clear all 0-20 Hz
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// bins for this. With small window sizes you probably don't want this as it would result in
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// a significant low-pass filter. When it's disabled, the DC bin will also be compressed.
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let first_non_dc_bin_idx =
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(20.0 / ((self.buffer_config.sample_rate / 2.0) / num_bins as f32)).floor() as usize
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+ 1;
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// The overlap gain compensation is based on a squared Hann window, which will sum perfectly
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// at four times overlap or higher. We'll apply a regular Hann window before the analysis
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// and after the synthesis.
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let gain_compensation: f32 =
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((overlap_times as f32 / 4.0) * 1.5).recip() / window_size as f32;
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// We'll apply the square root of the total gain compensation at the DFT and the IDFT
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// stages. That way the compressor threshold values make much more sense. This version of
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// Spectral Compressor does not have in input gain option and instead has the curve
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// threshold option. When sidechaining is enabled this is used to gain up the sidechain
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// signal instead.
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let input_gain = gain_compensation.sqrt();
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let output_gain = self.params.global.output_gain.value() * gain_compensation.sqrt();
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// TODO: Auto makeup gain
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// This is mixed in later with latency compensation applied
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self.dry_wet_mixer.write_dry(buffer);
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match self.params.threshold.mode.value() {
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compressor_bank::ThresholdMode::Internal => self.stft.process_overlap_add(
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buffer,
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overlap_times,
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|channel_idx, real_fft_buffer| {
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process_stft_main(
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channel_idx,
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real_fft_buffer,
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&mut self.complex_fft_buffer,
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fft_plan,
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&self.window_function,
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&self.params,
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&mut self.compressor_bank,
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input_gain,
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output_gain,
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overlap_times,
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first_non_dc_bin_idx,
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)
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},
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),
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compressor_bank::ThresholdMode::SidechainMatch
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| compressor_bank::ThresholdMode::SidechainCompress => {
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self.stft.process_overlap_add_sidechain(
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buffer,
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[&aux.inputs[0]],
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overlap_times,
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|channel_idx, sidechain_buffer_idx, real_fft_buffer| {
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if sidechain_buffer_idx.is_some() {
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process_stft_sidechain(
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channel_idx,
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real_fft_buffer,
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&mut self.complex_fft_buffer,
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fft_plan,
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&self.window_function,
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&mut self.compressor_bank,
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input_gain,
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);
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} else {
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process_stft_main(
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channel_idx,
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real_fft_buffer,
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&mut self.complex_fft_buffer,
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fft_plan,
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&self.window_function,
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&self.params,
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&mut self.compressor_bank,
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input_gain,
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output_gain,
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overlap_times,
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first_non_dc_bin_idx,
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)
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}
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},
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)
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}
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}
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self.dry_wet_mixer.mix_in_dry(
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buffer,
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self.params
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.global
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.dry_wet_ratio
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.smoothed
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.next_step(buffer.samples() as u32),
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// The dry and wet signals are in phase, so we can do a linear mix
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dry_wet_mixer::MixingStyle::Linear,
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self.stft.latency_samples() as usize,
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);
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ProcessStatus::Normal
|
|
}
|
|
}
|
|
|
|
impl SpectralCompressor {
|
|
fn window_size(&self) -> usize {
|
|
1 << self.params.global.window_size_order.value() as usize
|
|
}
|
|
|
|
fn overlap_times(&self) -> usize {
|
|
1 << self.params.global.overlap_times_order.value() as usize
|
|
}
|
|
|
|
/// `window_size` should not exceed `MAX_WINDOW_SIZE` or this will allocate.
|
|
fn resize_for_window(&mut self, window_size: usize) {
|
|
// The FFT algorithms for this window size have already been planned in
|
|
// `self.plan_for_order`, and all of these data structures already have enough capacity, so
|
|
// we just need to change some sizes.
|
|
self.stft.set_block_size(window_size);
|
|
self.window_function.resize(window_size, 0.0);
|
|
util::window::hann_in_place(&mut self.window_function);
|
|
self.complex_fft_buffer
|
|
.resize(window_size / 2 + 1, Complex32::default());
|
|
|
|
// This also causes the thresholds and ratios to be updated on the next STFT process cycle.
|
|
self.compressor_bank
|
|
.resize(&self.buffer_config, window_size);
|
|
self.compressor_bank.reset();
|
|
}
|
|
}
|
|
|
|
// These separate functions are needed to avoid having to either duplicate the main process function
|
|
// or always do the sidechain STFT. You can't do partial borrows and call `&mut self` methods at the
|
|
// same time.
|
|
|
|
/// The main process function inside of the STFT callback. If the sidechaining option is
|
|
/// enabled, another callback will run just before this to set up the siddechain frequency
|
|
/// spectrum magnitudes.
|
|
#[allow(clippy::too_many_arguments)]
|
|
fn process_stft_main(
|
|
channel_idx: usize,
|
|
real_fft_buffer: &mut [f32],
|
|
complex_fft_buffer: &mut [Complex32],
|
|
fft_plan: &mut Plan,
|
|
window_function: &[f32],
|
|
params: &SpectralCompressorParams,
|
|
compressor_bank: &mut compressor_bank::CompressorBank,
|
|
input_gain: f32,
|
|
output_gain: f32,
|
|
overlap_times: usize,
|
|
first_non_dc_bin_idx: usize,
|
|
) {
|
|
// We'll window the input with a Hann function to avoid spectral leakage. The input gain
|
|
// here also contains a compensation factor for the forward FFT to make the compressor
|
|
// thresholds make more sense.
|
|
for (sample, window_sample) in real_fft_buffer.iter_mut().zip(window_function) {
|
|
*sample *= window_sample * input_gain;
|
|
}
|
|
|
|
// RustFFT doesn't actually need a scratch buffer here, so we'll pass an empty buffer
|
|
// instead
|
|
fft_plan
|
|
.r2c_plan
|
|
.process_with_scratch(real_fft_buffer, complex_fft_buffer, &mut [])
|
|
.unwrap();
|
|
|
|
// This is where the magic happens
|
|
compressor_bank.process(
|
|
complex_fft_buffer,
|
|
channel_idx,
|
|
params,
|
|
overlap_times,
|
|
first_non_dc_bin_idx,
|
|
);
|
|
|
|
// Inverse FFT back into the scratch buffer. This will be added to a ring buffer
|
|
// which gets written back to the host at a one block delay.
|
|
fft_plan
|
|
.c2r_plan
|
|
.process_with_scratch(complex_fft_buffer, real_fft_buffer, &mut [])
|
|
.unwrap();
|
|
|
|
// Apply the window function once more to reduce time domain aliasing. The gain
|
|
// compensation compensates for the squared Hann window that would be applied if we
|
|
// didn't do any processing at all as well as the FFT+IFFT itself.
|
|
for (sample, window_sample) in real_fft_buffer.iter_mut().zip(window_function) {
|
|
*sample *= window_sample * output_gain;
|
|
}
|
|
}
|
|
|
|
/// The analysis process function inside of the STFT callback used to compute the frequency
|
|
/// spectrum magnitudes from the sidechain input if the sidechaining option is enabled. All
|
|
/// sidechain channels will be processed before processing the main input
|
|
fn process_stft_sidechain(
|
|
channel_idx: usize,
|
|
real_fft_buffer: &mut [f32],
|
|
complex_fft_buffer: &mut [Complex32],
|
|
fft_plan: &mut Plan,
|
|
window_function: &[f32],
|
|
compressor_bank: &mut compressor_bank::CompressorBank,
|
|
input_gain: f32,
|
|
) {
|
|
// The sidechain input should be gained, scaled, and windowed the exact same was as the
|
|
// main input as it's used for analysis
|
|
for (sample, window_sample) in real_fft_buffer.iter_mut().zip(window_function) {
|
|
*sample *= window_sample * input_gain;
|
|
}
|
|
|
|
fft_plan
|
|
.r2c_plan
|
|
.process_with_scratch(real_fft_buffer, complex_fft_buffer, &mut [])
|
|
.unwrap();
|
|
compressor_bank.process_sidechain(complex_fft_buffer, channel_idx);
|
|
}
|
|
|
|
impl ClapPlugin for SpectralCompressor {
|
|
const CLAP_ID: &'static str = "nl.robbertvanderhelm.spectral-compressor";
|
|
const CLAP_DESCRIPTION: Option<&'static str> = Some("Turn things into pink noise on demand");
|
|
const CLAP_MANUAL_URL: Option<&'static str> = Some(Self::URL);
|
|
const CLAP_SUPPORT_URL: Option<&'static str> = None;
|
|
const CLAP_FEATURES: &'static [ClapFeature] = &[
|
|
ClapFeature::AudioEffect,
|
|
ClapFeature::Stereo,
|
|
ClapFeature::Mono,
|
|
ClapFeature::PhaseVocoder,
|
|
ClapFeature::Compressor,
|
|
ClapFeature::Custom("nih:spectral"),
|
|
ClapFeature::Custom("nih:sosig"),
|
|
];
|
|
}
|
|
|
|
impl Vst3Plugin for SpectralCompressor {
|
|
const VST3_CLASS_ID: [u8; 16] = *b"SpectrlComprRvdH";
|
|
const VST3_SUBCATEGORIES: &'static [Vst3SubCategory] = &[
|
|
Vst3SubCategory::Fx,
|
|
Vst3SubCategory::Dynamics,
|
|
Vst3SubCategory::Custom("Spectral"),
|
|
];
|
|
}
|
|
|
|
nih_export_clap!(SpectralCompressor);
|
|
nih_export_vst3!(SpectralCompressor);
|