From e7bb36d655d7694271a314fd03354bb86d928020 Mon Sep 17 00:00:00 2001
From: Albin Chaboissier <chalbin73@gmail.com>
Date: Fri, 3 Oct 2025 02:19:32 +0200
Subject: [PATCH] framed com

---
 src/main.rs | 128 ++++++++++++++++++++++++++++++++++++++--------------
 1 file changed, 95 insertions(+), 33 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index bd1fdff..7629344 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -5,12 +5,11 @@ use std::{
     f32::consts::PI,
     fs::File,
     i16,
-    io::{Read, Write},
+    io::{self, Read, Write},
     ops::{Add, Div, Mul, Sub},
     os::unix::thread,
     sync::{
-        Arc,
-        mpsc::{self, Receiver, Sender, TryRecvError, sync_channel},
+        atomic::{AtomicU32, Ordering}, mpsc::{self, channel, sync_channel, Receiver, Sender, TryRecvError}, Arc
     },
     time::Duration,
 };
@@ -35,7 +34,7 @@ use cpal::{
 use fft::DFTAlgorithm;
 use nco::Nco;
 
-use eframe::egui::{self, Color32, Context, Vec2b, debug_text::print};
+use eframe::egui::{self, debug_text::print, decode_animated_image_uri, Color32, Context, Vec2b};
 use egui_plot::{self, Bar, BarChart, Legend, Line, LineStyle, Plot, PlotPoints, VLine};
 use plotters::style::Color;
 use rand::{seq::index::sample, Rng};
@@ -263,6 +262,9 @@ fn demodulator(
         );
     
     // Timing recovery
+    let mut preamble_count = 0;
+    let mut bit_index = 0;
+    let mut last = 0u8;
     while let Ok(real_sample) = rx.recv() {
         let iq = iq_sampler.sample(real_sample);
 
@@ -272,10 +274,35 @@ fn demodulator(
 
         let matched = matched_filter.next_real(pos_energy.mag() - neg_energy.mag());
 
-        if let Some((_, eye)) = elg.next_eye(matched)
+        if let Some((bit, eye)) = elg.next_eye(matched)
         {
             let _ = eye_sender.send(eye);
             ctx.request_repaint();
+
+            last <<= 1;
+            last |= bit as u8;
+
+            if preamble_count >= 2
+            {
+                bit_index += 1;
+                if bit_index == 8
+                {
+                    if last == 4
+                    {
+                        println!();
+                        preamble_count = 0;
+                    }
+                    else
+                    {
+                        print!("{}", last as char);
+                        bit_index = 0;
+                    }
+                }
+            }
+            if last == 0xD8
+            {
+                preamble_count += 1;
+            }
         }
     }
 }
@@ -436,39 +463,74 @@ fn modulate() {
     let sample_rate = 48000;
     let baud_rate = BAUD_RATE;
 
-    // File to modulate
-    let f = File::open("s.txt").unwrap();
-    let mut bitstream = std::iter::repeat_n(0b01010101u8, 1)
-        .chain(std::iter::repeat_n(0b01010111u8, 1))
-        .chain(f.bytes().map(|x| x.unwrap()))
-        .chain(std::iter::repeat_n(0u8, 1))
-        .flat_map(byte_to_bits);
+    let host = cpal::default_host();
+    let device = host.default_output_device().unwrap();
+    let mut supported_configs_range = device.supported_output_configs().unwrap();
+    let supported_config = supported_configs_range
+        .find(|config| config.sample_format() == cpal::SampleFormat::F32
+            && config.min_sample_rate().0 <= 48000
+            && config.max_sample_rate().0 >= 48000)
+        .expect("Device does not support 48kHz f32 output");
+    let config = supported_config.with_sample_rate(cpal::SampleRate(48_000)).config();
 
-    let mut modulator = BFSKMod::new(
-        sample_rate / baud_rate,
-        units::frequency::hz_to_rad_per_sample(deviation, sample_rate as f32),
-        &mut bitstream,
-    );
 
-    let mut lo = Nco::new(units::frequency::hz_to_rad_per_sample(
-        frequency,
-        sample_rate as f32,
-    ));
+    loop
+    {
+        let mut buffer = String::new();
+        let stdin = io::stdin(); // We get `Stdin` here.
+        stdin.read_line(&mut buffer).unwrap();
 
-    let spec = hound::WavSpec {
-        channels: 1,
-        sample_rate,
-        bits_per_sample: 16,
-        sample_format: hound::SampleFormat::Int,
-    };
+        // Construct payload
+        let mut bitstream = 
+            std::iter::repeat_n(0b01010101u8, 32)
+            .chain(std::iter::repeat_n(0b11011000, 1))
+            .chain(buffer.bytes())
+            .chain(std::iter::repeat_n(4u8, 32))
+            .flat_map(byte_to_bits);
 
-    let mut writer = hound::WavWriter::create("audio/modulated.wav", spec).unwrap();
-    for (s, up) in modulator.zip(lo) {
-        let sample = (s * up).re; // Project to I coords
-        let amplitude = i16::MAX as f32;
-        writer.write_sample((sample * amplitude) as i16).unwrap();
+        let mut modulator = BFSKMod::new(
+            sample_rate / baud_rate,
+            units::frequency::hz_to_rad_per_sample(deviation, sample_rate as f32),
+            &mut bitstream,
+        );
+
+        let mut lo = Nco::new(units::frequency::hz_to_rad_per_sample(
+                frequency,
+                sample_rate as f32,
+        ));
+
+        // To send
+        let stream = modulator.zip(lo)
+            .map(|(s, up)| (s * up).re)
+            .collect::<Vec<_>>();
+
+        let sample_clock = Arc::new(AtomicU32::new(0));
+        let (tx, rx) = channel::<()>();
+
+        let stream = device.build_output_stream(
+            &config,
+            move |data: &mut [f32], _: &cpal::OutputCallbackInfo| {
+                for d in data.iter_mut()
+                {
+                    if sample_clock.load(Ordering::Relaxed) as usize == stream.len()
+                    {
+                        tx.send(()).unwrap();
+                        break;
+                    }
+                    *d = stream[sample_clock.fetch_add(1, Ordering::Relaxed) as usize]
+                }
+
+            },
+            move |err| {
+                eprintln!("Stream error: {}", err);
+            },
+            None
+        ).unwrap();
+
+        stream.play().unwrap();
+        let _ = rx.recv();
+        stream.pause().unwrap();
     }
-    writer.finalize().unwrap();
 }
 
 fn byte_to_bits(byte: u8) -> Vec<bool> {