begin correcting fft stuff. need to find a way to sync to signal

run.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+set -e
+ROOT="$(git rev-parse --show-toplevel)"
+ROOT="${ROOT:-.}"
+cargo build --release --bin sang
+sudo setcap CAP_NET_ADMIN+ep "$ROOT/target/release/sang"
+"$ROOT/target/release/sang"

src/audio_receiver/input_dsp.rs

@@ -1,13 +1,47 @@
-use cpal::{FromSample, Sample};
+use std::io::Write;
+use std::collections::VecDeque;
+
+use cpal::{FromSample, Sample, SampleRate};
 
 use rustfft::{FftPlanner, num_complex::Complex};
 
-pub fn take_input_pcm<T>(pcm: &[T], channel: &tokio::sync::mpsc::Sender<Vec<f64>>) where T: Sample + FromSample<f64> + std::fmt::Debug, f64: FromSample<T> {
-    let mut pcm_complex = pcm.iter().map(|s| Complex { re: s.to_sample::<f64>(), im: 0.0f64 }).collect::<Vec<Complex<_>>>();
+pub fn take_input_pcm<T>(
+    pcm: &[T],
+    sample_rate: SampleRate,
+    channel: &tokio::sync::mpsc::Sender<Vec<f64>>,
+    pcm_buffer: &mut VecDeque<Complex<f64>>,
+) where 
+    T: ToString + Sample + FromSample<f64> + std::fmt::Debug,
+    f64: FromSample<T>
+{
+    // TODO: Obtain this information during the handshake
+    let fft_size = 320
+
+    pcm_buffer.extend(
+        pcm
+            .iter()
+            .map(|s| Complex { re: s.to_sample::<f64>(), im: 0.0f64 })
+    );
 
     let mut fft_planner = FftPlanner::<f64>::new();
-    let fft_machine = fft_planner.plan_fft_forward(pcm.len());
-    fft_machine.process(&mut pcm_complex);
-    let fft_out = pcm_complex.iter().map(|n| n.norm()).collect::<Vec<_>>();
-    println!("{:?}",fft_out);
+    let fft_machine = fft_planner.plan_fft_forward(FFT_SIZE); // TODO: cfgable
+
+    while pcm_buffer.len() >= FFT_SIZE {
+        let mut fft_frame =
+            pcm_buffer.drain(..FFT_SIZE).collect::<Vec<Complex<f64>>>();
+        fft_machine.process(&mut fft_frame);
+
+        
+
+        /*for (i, s) in fft_frame.iter().enumerate() {
+            let freq = sample_rate.0 as usize * i / FFT_SIZE;
+            let ampl = s.norm();
+            let confidence = ampl;
+            if ampl > 50.0 {
+                println!("{:?}: {:?}", freq, ampl);
+            }
+
+            // soon: confidence = ampl / |freq_target - freq_observed|
+        }*/
+    }
 }

src/audio_receiver/mod.rs

@@ -5,6 +5,8 @@ use cpal::{FromSample, Sample, SampleFormat};
 
 use tracing::{info, trace, warn};
 
+use std::collections::VecDeque;
+
 mod input_dsp;
 use self::input_dsp::take_input_pcm;
 
@@ -16,78 +18,101 @@ pub fn audio_receiver_main(
     let cpal_input_config = cpal_input.supported_input_configs()
         .context("could not find a suitable audio input configuration. are you root, trying to use a normal user's audio stack? try setting the capability CAP_NET_ADMIN=ep on this binary, and running as the user who is running the audio stack.")?
         .max_by_key(|cfg| {
-        match cfg.sample_format() {
-            SampleFormat::U8 => 10,
-            SampleFormat::I8 => 11,
-            SampleFormat::U16 => 20,
-            SampleFormat::I16 => 21,
-            SampleFormat::U32 => 30,
-            SampleFormat::I32 => 31,
-            SampleFormat::F32 => 40,
-            SampleFormat::F64 => 50,
-            SampleFormat::U64 => 60,
-            SampleFormat::I64 => 61,
-            x => { warn!("Backend offered unknown sample format {x}",); -999 }
-        }
+            if cfg.channels() > 1 { return -999; }
+            match cfg.sample_format() {
+                SampleFormat::U8 => 10,
+                SampleFormat::I8 => 11,
+                SampleFormat::U16 => 20,
+                SampleFormat::I16 => 21,
+                SampleFormat::U32 => 30,
+                SampleFormat::I32 => 31,
+                SampleFormat::F32 => 40,
+                SampleFormat::F64 => 50,
+                SampleFormat::U64 => 60,
+                SampleFormat::I64 => 61,
+                x => { warn!("Backend offered unknown sample format {x}",); -999 }
+            }
     }).expect("input device has no supported configurations available")
         .with_max_sample_rate();
+        //.with_sample_rate(cpal::SampleRate(8000));
+
+    let sample_rate = cpal_input_config.sample_rate();
 
     info!(
         "input samples are {} @ {}hz", 
         &cpal_input_config.sample_format(),
-        &cpal_input_config.sample_rate().0,
+        sample_rate.0,
     );
 
     let failed_pcm_take = move |e| {
         warn!("dropped some PCM data on input stream?! {}", e);
     };
 
+    let mut pcm_buf: VecDeque<rustfft::num_complex::Complex<f64>> =
+        vec![].into();
+
     let input_stream = match cpal_input_config.sample_format() {
         cpal::SampleFormat::U8 => cpal_input.build_input_stream(
             &cpal_input_config.into(),
-            move |pcm, _: &_| take_input_pcm::<u8>(pcm, &tx_for_demod),
+            move |pcm, _: &_| {
+                take_input_pcm::<u8>(pcm, sample_rate, &tx_for_demod, &mut pcm_buf)
+            },
             failed_pcm_take,
             None,
         ).context("failed to build input stream")?,
         cpal::SampleFormat::I8 => cpal_input.build_input_stream(
             &cpal_input_config.into(),
-            move |pcm, _: &_| take_input_pcm::<i8>(pcm, &tx_for_demod),
+            move |pcm, _: &_| {
+                take_input_pcm::<i8>(pcm, sample_rate, &tx_for_demod, &mut pcm_buf)
+            },
             failed_pcm_take,
             None,
         ).context("failed to build input stream")?,
         cpal::SampleFormat::I16 => cpal_input.build_input_stream(
             &cpal_input_config.into(),
-            move |pcm, _: &_| take_input_pcm::<i16>(pcm, &tx_for_demod),
+            move |pcm, _: &_| {
+                take_input_pcm::<i16>(pcm, sample_rate, &tx_for_demod, &mut pcm_buf)
+            },
             failed_pcm_take,
             None,
         ).context("failed to build input stream")?,
         cpal::SampleFormat::I32 => cpal_input.build_input_stream(
             &cpal_input_config.into(),
-            move |pcm, _: &_| take_input_pcm::<i32>(pcm, &tx_for_demod),
+            move |pcm, _: &_| {
+                take_input_pcm::<i32>(pcm, sample_rate, &tx_for_demod, &mut pcm_buf)
+            },
             failed_pcm_take,
             None,
         ).context("failed to build input stream")?,
         cpal::SampleFormat::F32 => cpal_input.build_input_stream(
             &cpal_input_config.into(),
-            move |pcm, _: &_| take_input_pcm::<f32>(pcm, &tx_for_demod),
+            move |pcm, _: &_| {
+                take_input_pcm::<f32>(pcm, sample_rate, &tx_for_demod, &mut pcm_buf)
+            },
             failed_pcm_take,
             None,
         ).context("failed to build input stream")?,
         cpal::SampleFormat::F64 => cpal_input.build_input_stream(
             &cpal_input_config.into(),
-            move |pcm, _: &_| take_input_pcm::<f64>(pcm, &tx_for_demod),
+            move |pcm, _: &_| {
+                take_input_pcm::<f64>(pcm, sample_rate, &tx_for_demod, &mut pcm_buf)
+            },
             failed_pcm_take,
             None,
         ).context("failed to build input stream")?,
         cpal::SampleFormat::U64 => cpal_input.build_input_stream(
             &cpal_input_config.into(),
-            move |pcm, _: &_| take_input_pcm::<u64>(pcm, &tx_for_demod),
+            move |pcm, _: &_| {
+                take_input_pcm::<u64>(pcm, sample_rate, &tx_for_demod, &mut pcm_buf)
+            },
             failed_pcm_take,
             None,
         ).context("failed to build input stream")?,
         cpal::SampleFormat::I64 => cpal_input.build_input_stream(
             &cpal_input_config.into(),
-            move |pcm, _: &_| take_input_pcm::<i64>(pcm, &tx_for_demod),
+            move |pcm, _: &_| {
+                take_input_pcm::<i64>(pcm, sample_rate, &tx_for_demod, &mut pcm_buf)
+            },
             failed_pcm_take,
             None,
         ).context("failed to build input stream")?,

src/audio_transmitter/mod.rs

@@ -49,10 +49,12 @@ pub fn audio_transmitter_main(
         warn!("dropped some PCM data on output stream?! {}", e);
     };
 
+    // These are mathematically chosen to make things easier for now.
+    //
     // TODO: from cli
     let mut carrier = crate::dsp_common::carrier::TwoStateCarrier::new(
         2400,                                  // freq_low
-        2800,                                  // freq_high
+        3200,                                  // freq_high
         cpal_output_config.sample_rate().0, // sample_rate
         1200,                                    // symbol_rate
     );