[threebandwidth] create and implement crate

README.md

@@ -55,6 +55,7 @@ the following is the current list of plugins
 - robotuna: automatic pitch correction
 - hysteria: hysteresis nonlinear effect
 - threebandeq: 3 band eq
+- threebandwidth: 3 band stereo widener
 
 ### basic_gain
 
@@ -132,7 +133,7 @@ original source [here](https://ccrma.stanford.edu/~jatin/ComplexNonlinearities/H
 
 turn the values up for loud and distorted. don't set them all to the max at once though, that doesn't sound as interesting
 
-### threebandeq [WIP]
+### threebandeq
 
 simple three band equalizer
 
@@ -145,6 +146,19 @@ parameters:
 
 low band goes from 0hz to `low band`, mid band goes from `low band` to `high band`, high band goes from `high band` to half the sample rate
 
+### threebandwidth
+
+three band stereo widener
+
+parameters:
+- `low band`: frequency at which the low band ends
+- `high band`: frequency at which the high band starts
+- `low width`: width for the low band
+- `mid width`: width for the mid band
+- `high width`: width for the high band
+
+bands work as they do in `threebandeq`. the width parameters control how wide an audio signal should be in the stereo field. `width` of 1 leaves the audio as is, `width` of 0 makes it mono, values between 0 and 1 decrease the stereo width, values over 1 increase it.
+
 ## contributing
 
 issues and prs are welcome, but please open an issue before making any big pr, i don't wanna have to reject a pr where you have put a lot of effort on

crates/threebandeq/src/lib.rs

@@ -1,8 +1,6 @@
 #![allow(incomplete_features)]
 #![feature(generic_associated_types)]
 
-// https://www.musicdsp.org/en/latest/Filters/236-3-band-equaliser.html
-
 use baseplug::{Plugin, ProcessContext};
 use serde::{Deserialize, Serialize};
 
@@ -108,4 +106,4 @@ impl Plugin for ThreeBandEq {
     }
 }
 
-baseplug::vst2!(ThreeBandEq, b"tAnE");
+baseplug::vst2!(ThreeBandEq, b"3beq");

crates/threebandwidth/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "threebandwidth"
+version = "0.1.0"
+edition = "2018"
+
+[lib]
+crate-type = ["cdylib"]
+
+[dependencies]
+baseplug = { git = "https://github.com/wrl/baseplug.git", rev = "9cec68f31cca9c0c7a1448379f75d92bbbc782a8" }
+serde = "1.0.126"
+
+utils = { path = "../utils" }

crates/threebandwidth/src/lib.rs

@@ -0,0 +1,106 @@
+#![allow(incomplete_features)]
+#![feature(generic_associated_types)]
+
+use baseplug::{Plugin, ProcessContext};
+use serde::{Deserialize, Serialize};
+
+use utils::threeband::*;
+
+baseplug::model! {
+    #[derive(Debug, Serialize, Deserialize)]
+    struct ThreeBandEqModel {
+        #[model(min = 0.0, max = 15000.0)]
+        #[parameter(name = "low band")]
+        low_band: f32,
+        #[model(min = 0.0, max = 15000.0)]
+        #[parameter(name = "mid band")]
+        high_band: f32,
+
+        #[model(min = 0.0, max = 3.0)]
+        #[parameter(name = "low width")]
+        low_width: f32,
+        #[model(min = 0.0, max = 3.0)]
+        #[parameter(name = "mid width")]
+        mid_width: f32,
+        #[model(min = 0.0, max = 3.0)]
+        #[parameter(name = "high width")]
+        high_width: f32,
+    }
+}
+
+impl Default for ThreeBandEqModel {
+    fn default() -> Self {
+        Self {
+            low_band: 800.0,
+            high_band: 5000.0,
+
+            low_width: 1.0,
+            mid_width: 1.0,
+            high_width: 1.0,
+        }
+    }
+}
+
+#[derive(Default)]
+struct ThreeBandWidth {
+    l: ThreeBandSplitter,
+    r: ThreeBandSplitter,
+}
+
+impl Plugin for ThreeBandWidth {
+    const NAME: &'static str = "threebandwidth";
+    const PRODUCT: &'static str = "threebandwidth";
+    const VENDOR: &'static str = "unnieversal";
+
+    const INPUT_CHANNELS: usize = 2;
+    const OUTPUT_CHANNELS: usize = 2;
+
+    type Model = ThreeBandEqModel;
+
+    #[inline]
+    fn new(_sample_rate: f32, _model: &ThreeBandEqModel) -> Self {
+        // Default cause we want to start with 0s in everything
+        Self::default()
+    }
+
+    #[inline]
+    fn process(&mut self, model: &ThreeBandEqModelProcess, ctx: &mut ProcessContext<Self>) {
+        let input = &ctx.inputs[0].buffers;
+        let output = &mut ctx.outputs[0].buffers;
+
+        let sr = ctx.sample_rate;
+
+        for i in 0..ctx.nframes {
+            // frequencies
+            let lf = model.low_band[i];
+            let hf = model.high_band[i];
+
+            // split into bands
+            let (low_l, mid_l, high_l) = self.l.process(input[0][i], lf, hf, sr);
+            let (low_r, mid_r, high_r) = self.r.process(input[1][i], lf, hf, sr);
+
+            // widen each band
+            let (low_l, low_r) = wide(model.low_width[i], low_l, low_r);
+            let (mid_l, mid_r) = wide(model.mid_width[i], mid_l, mid_r);
+            let (high_l, high_r) = wide(model.high_width[i], high_l, high_r);
+
+            output[0][i] = low_l + mid_l + high_l;
+            output[1][i] = low_r + mid_r + high_r;
+        }
+    }
+}
+
+// From https://www.musicdsp.org/en/latest/Effects/256-stereo-width-control-obtained-via-transfromation-matrix.html
+
+fn wide(width: f32, l: f32, r: f32) -> (f32, f32) {
+    let tmp = 1.0 / f32::max(1.0 + width, 2.0);
+    let coef_m = tmp;
+    let coef_s = width * tmp;
+
+    let m = (l + r) * coef_m;
+    let s = (r - l) * coef_s;
+
+    (m - s, m + s)
+}
+
+baseplug::vst2!(ThreeBandWidth, b"3bsw");

crates/utils/src/threeband.rs

@@ -1,3 +1,5 @@
+// https://www.musicdsp.org/en/latest/Filters/236-3-band-equaliser.html
+
 /// Very small amount
 const VSA: f32 = 1.0 / 4294967295.0;