From: Max Value <greenwoodw50@gmail.com>
Date: Mon, 12 Jan 2026 12:56:29 +0000 (+0000)
Subject: Added filtering to feedback and the main out
X-Git-Url: https://git.ozva.co.uk/?a=commitdiff_plain;h=refs%2Fheads%2Fmain;p=rust_fft

Added filtering to feedback and the main out

untested!
---

diff --git a/Cargo.toml b/Cargo.toml
index 9532aec..4a1f932 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -18,6 +18,7 @@ rand = "0.9.2"
 nokhwa = {version = "0.10.10", features = ["input-native"]}
 relative-path = "2.0.1"
 yuv = "0.8.9"
+lowpass-filter = "0.3.2"
 
 [build-dependencies]
 cc = "1.0"
diff --git a/src/main.rs b/src/main.rs
index 5184f4d..0d4153c 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -15,6 +15,8 @@ mod sample_buffer;
 use image_array::ImageArray;
 use sample_buffer::SampleBuffer;
 
+use lowpass_filter::LowpassFilter;
+
 const WINDOW_SIZE: usize = 128;
 const CHUNK_SIZE: usize = 72;
 const SPECTOGRAM_AREA: usize = WINDOW_SIZE * CHUNK_SIZE;
@@ -48,7 +50,16 @@ const LUT_LENGTH: usize = LUT_SIZE * LUT_SIZE * LUT_SIZE * 3;
 const DEBUG_MODE: bool = true;
 
 const CALIBRATION_PATH: &str = "./test/calibration.jpg";
-const AUDIO_PATH: &str = "/home/will/Downloads/Adducci - Around the Horn.wav";
+const AUDIO_PATH: &str = "./test/example.wav";
+
+// feedback config
+const WET: f32 = 0.0;
+const DRY: f32 = 1.0;
+
+// audio effects and filtering
+const MAIN_LOWPASS: f32 = 20000.0;
+const FEEDBACK_LOWPASS: f32 = 20000.0;
+const FILTER_SCALING: f32 = 1. / 65535.; // to bring any signal down to +-1
 
 extern "C" {
   fn GetHomography(camera_ptr: usize, homography_ptr: usize);
@@ -106,6 +117,10 @@ fn main () -> Result<(), Box<dyn std::error::Error>> {
 	let mut reader = hound::WavReader::open(audio_path).unwrap();
 	let file_rate = reader.spec().sample_rate;
 
+	// setup the lowpass filters
+	let main_lowpass = LowpassFilter::new(file_rate, MAIN_LOWPASS);
+	let feedback_lowpass = LowpassFilter::new(file_rate, FEEDBACK_LOWPASS);
+
 	// setup audio output and build output stream
 	let host = cpal::default_host();
 	let device = host.default_output_device().expect("No output device available");
@@ -159,15 +174,19 @@ fn main () -> Result<(), Box<dyn std::error::Error>> {
 			if rx.recv().unwrap() {
 				let mut write_buffer = sample_buffer.lock().unwrap();
 				for (i, x) in write_buffer[SPECTOGRAM_AREA..].iter_mut().enumerate() {
-					*x = buffer[i].re as i16;
+					let value = main_lowpass.run(buffer[i].re / i16::MAX as f32);
+					*x = (value * i16::MAX) as i16;
 				}
 			}
 
 			i = 0;
 		}
-		let value = sample.unwrap_or_default();
 		// if buffer is not full convert value and add to buffer
-		buffer[i] = Complex{re: value as f32, im: 0f32};
+		let mut value = sample.unwrap_or_default() as f32;
+		let feedback_value = feedback_lowpass.run(buffer[i].re / i16::MAX as f32);
+		value = (value * DRY) + (feedback_value * i16::MAX * WET);
+
+		buffer[i] = Complex{re: value, im: 0f32};
 		i += 1;
 	}
 
diff --git a/test/example.wav b/test/example.wav
index 02c44de..75ac385 100644
Binary files a/test/example.wav and b/test/example.wav differ
diff --git a/todo b/todo
index f88857f..52b5a35 100644
--- a/todo
+++ b/todo
@@ -34,3 +34,7 @@ GPU PERFORMANCE ISSUES:
 CAPTURE ISSUES:
 - check nokhwa fps, res, etc
 - reinstate the read loop
+
+AUDIO ISSUES:
+- disable the feedback mix code
+- disable the filtering code