create audio sync packet

Cargo.lock

@@ -105,7 +105,7 @@ dependencies = [
  "cpal",
  "env_logger",
  "log",
- "rustfft",
+ "realfft",
  "textplots",
 ]
 
@@ -772,6 +772,15 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "realfft"
+version = "3.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "390252372b7f2aac8360fc5e72eba10136b166d6faeed97e6d0c8324eb99b2b1"
+dependencies = [
+ "rustfft",
+]
+
 [[package]]
 name = "regex"
 version = "1.11.1"

Cargo.toml

@@ -13,6 +13,6 @@ log = "0.4"
 color-eyre = "0.6"
 
 cpal = { version = "0.15", features = ["jack"] }
-rustfft = "6.2"
+realfft = "3.4"
 
 textplots = "0.8"

src/main.rs

@@ -1,16 +1,16 @@
-use std::{sync::mpsc, thread::sleep, time::Duration};
+use std::{cmp::Ordering, sync::mpsc, thread::sleep, time::Duration};
 
-use color_eyre::eyre::bail;
+use color_eyre::eyre::{bail, Result};
 use cpal::{
     traits::{DeviceTrait, HostTrait, StreamTrait},
     BufferSize, HostId, SupportedBufferSize,
 };
 use log::{debug, error, info, trace};
-use rustfft::{
-    num_complex::{Complex, ComplexFloat},
-    FftPlanner,
+use realfft::{
+    num_complex::{Complex, Complex32, ComplexFloat},
+    RealFftPlanner, RealToComplex,
 };
-use textplots::{Chart, Plot, Shape};
+use textplots::{Chart, LabelBuilder, LabelFormat, Plot, Shape};
 
 fn main() -> color_eyre::Result<()> {
     env_logger::init();
@@ -44,27 +44,27 @@ fn main() -> color_eyre::Result<()> {
     config.channels = 1;
     debug!("Using config {config:?}");
 
-    let mut planner = FftPlanner::<f32>::new();
+    let mut planner = RealFftPlanner::<f32>::new();
     let fft = planner.plan_fft_forward(buffer_size as usize);
-    let mut fft_data = vec![Complex::new(0.0, 0.0); buffer_size as usize];
-    let mut fft_scratch = vec![Complex::new(0.0, 0.0); buffer_size as usize];
+    let mut fft_input = fft.make_input_vec();
+    let mut fft_output = fft.make_output_vec();
     let (sender, receiver) = mpsc::channel();
 
     let stream = device.build_input_stream(
         &config,
-        move |data: &[f32], _| {
-            for i in 0..data.len() {
-                fft_data[i] = Complex::new(data[i], 0.0);
+        move |data: &[f32], _| match AudioSyncPacket::from_sample(
+            data,
+            fft.as_ref(),
+            &mut fft_input,
+            &mut fft_output,
+            config.sample_rate.0,
+        ) {
+            Ok(packet) => {
+                if let Err(e) = sender.send(packet) {
+                    error!("Unable to send packet: {e}");
                 }
-            let mut fft_output = vec![Complex::new(0.0, 0.0); data.len()];
-            fft.process_outofplace_with_scratch(
-                &mut fft_data[..],
-                &mut fft_output[..],
-                &mut fft_scratch[..],
-            );
-            if let Err(e) = sender.send(fft_output) {
-                error!("Unable to send fft output: {e}");
             }
+            Err(e) => error!("Unable to process audio data: {e}"),
         },
         |err| {
             error!("input stream error: {err}");
@@ -74,15 +74,149 @@ fn main() -> color_eyre::Result<()> {
 
     stream.play()?;
 
+    let mut previous_sample_smth = 0.0;
     loop {
-        let data = receiver.recv()?;
+        let mut data = receiver.recv()?;
+        data.sample_smth = 0.8f32.mul_add(previous_sample_smth, 0.2 * data.sample_raw);
+        previous_sample_smth = data.sample_smth;
+
         let plot_data: Vec<_> = data
-            .into_iter()
+            .fft_result
+            .iter()
             .enumerate()
-            .map(|(i, datum)| ((i as f32).log10(), datum.abs() / 1024.0.sqrt()))
+            .map(|(i, datum)| (i as f32, f32::from(*datum)))
             .collect();
-        Chart::new_with_y_range(200, 50, 0.0, 1024.0.log10(), 0.0, 2.0)
+        Chart::new_with_y_range(250, 50, 0.0, 16.0, 0.0, 255.0)
             .lineplot(&Shape::Bars(&plot_data[..]))
             .display();
     }
 }
+
+/// new "V2" audiosync struct - 44 Bytes
+#[repr(C, packed(1))]
+struct AudioSyncPacket {
+    /// "00002" for protocol version 2 (includes '\0' for c-style string termination)
+    header: [u8; 6],
+    /// Optional sound pressure as fixed point (8bit integer, 8bit fractional)
+    preasure: [u8; 2],
+    /// either "sample_raw" or "raw_sample_agc" depending on sound_agc setting
+    sample_raw: f32,
+    /// either "sample_avg" or "sample_agc" depending on sound_agc setting
+    sample_smth: f32,
+    /// 0 = no peak, >= 1 = peak detected, In future, this will also provide peak Magnitude
+    sample_peak: u8,
+    /// Optional rolling counter to track duplicate / out of order packets
+    frame_counter: u8,
+    /// 16 GEQ channels, each channel has one byte
+    fft_result: [u8; 16],
+    /// Optional number of zero crossings seen in 23ms
+    zero_crossing_count: u16,
+    /// Largest FFT result (raw value, can go up to 4096)
+    fft_magnitude: f32,
+    /// frequency (Hz) of largest FFT result
+    fft_major_peak: f32,
+}
+
+const _: () = assert!(size_of::<AudioSyncPacket>() == 44);
+
+impl AudioSyncPacket {
+    /// Create an `AudioSyncPacket` with only required information
+    pub const fn new(
+        sample_raw: f32,
+        sample_smth: f32,
+        sample_peak: u8,
+        fft_result: [u8; 16],
+        fft_magnitude: f32,
+        fft_major_peak: f32,
+    ) -> Self {
+        Self {
+            header: *b"00002\0",
+            preasure: [0, 0],
+            sample_raw,
+            sample_smth,
+            sample_peak,
+            frame_counter: 0,
+            fft_result,
+            zero_crossing_count: 0,
+            fft_magnitude,
+            fft_major_peak,
+        }
+    }
+
+    pub fn from_sample(
+        data: &[f32],
+        fft: &dyn RealToComplex<f32>,
+        fft_input: &mut [f32],
+        fft_output: &mut [Complex32],
+        sample_rate: u32,
+    ) -> Result<Self> {
+        // take the absolute value of the audio data
+        let abs_data: Vec<_> = data.iter().map(|sample| sample.abs()).collect();
+
+        // calculate peak  (raw level and peak level)
+        let raw_level = abs_data.iter().sum::<f32>() / data.len() as f32;
+        let peak_level = abs_data
+            .iter()
+            .max_by(|lhs, rhs| lhs.partial_cmp(rhs).unwrap_or(Ordering::Equal))
+            .copied()
+            .unwrap_or(0.0);
+        // scale peak level to u8
+        let peak_level = (peak_level * f32::from(u8::MAX)) as u8;
+
+        // calculate fft
+        fft_input[..].copy_from_slice(data);
+        fft.process(fft_input, fft_output)?;
+        let real_fft_output: Vec<_> = fft_output.iter().map(|value| value.abs()).collect();
+
+        // find dominant frequency
+        let (peak_index, peak) = real_fft_output
+            .iter()
+            .enumerate()
+            .max_by(|(_, lhs), (_, rhs)| lhs.partial_cmp(rhs).unwrap_or(Ordering::Equal))
+            .map(|(i, value)| (i, *value))
+            .unwrap_or_default();
+        let peak_frequency = (peak_index * sample_rate as usize) as f32 / data.len() as f32;
+
+        // select 16 [frequency bins](https://github.com/MoonModules/WLED/blob/fc173b3bc00694e59b653ca230133052b5476c05/usermods/audioreactive/audio_reactive.h#L733-L760)
+        let bins = [
+            86, 129, 216, 301, 430, 560, 818, 1120, 1421, 1895, 2412, 3015, 3704, 4479, 7106, 9259,
+        ]
+        .map(|frequency| frequency * data.len() / sample_rate as usize);
+        let mut fft_values = [0.0; 16];
+        fft_values[0] = real_fft_output[1..=bins[0]].iter().sum::<f32>() / (bins[0]) as f32;
+        for i in 1..fft_values.len() {
+            fft_values[i] = real_fft_output[bins[i - 1] + 1..=bins[i]]
+                .iter()
+                .sum::<f32>()
+                / (bins[i] - bins[i - 1] + 1) as f32;
+        }
+        fft_values[14] *= 0.88;
+        fft_values[15] *= 0.7;
+
+        // scale the fft values to u8
+        let mut fft_values_u8 = [0u8; 16];
+        let mut fft_max = fft_values
+            .iter()
+            .max_by(|lhs, rhs| lhs.partial_cmp(rhs).unwrap_or(Ordering::Equal))
+            .copied()
+            .unwrap_or(1.0);
+        if fft_max == 0.0 {
+            fft_max = 1.0;
+        }
+        for i in 0..fft_values.len() {
+            fft_values_u8[i] = (fft_values[i] * f32::from(u8::MAX) / fft_max) as u8;
+        }
+
+        // calculate fft magnitude sum
+        let fft_magnitude_sum = real_fft_output.iter().sum::<f32>();
+
+        Ok(Self::new(
+            raw_level,
+            0.0,
+            peak_level,
+            fft_values_u8,
+            fft_magnitude_sum,
+            peak_frequency,
+        ))
+    }
+}