Downmix the source from stereo to mono

1 files changed, 7 insertions, 6 deletions

diff --git a/src/main.rs b/src/main.rs
index 0814506..825d4e1 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -261,9 +261,10 @@ fn main() {
                 }
             }
 
+            // Downmix stereo to mono, apply (v/2 + i16::MAX/2), and normalise to [-1.0; 1.0]
             let buf: Vec<f32> = buf
-                .iter()
-                .map(|v| (v/2 + i16::MAX/2) as f32 / 32768.0)
+                .chunks_exact(2)
+                .map(|v| ((v[0]/2 + v[1]/2)/2 + i16::MAX/2) as f32 / 32768.0)
                 .collect();
 
             if let Some(w) = &mut in_debug {
@@ -283,7 +284,7 @@ fn main() {
 
     // Read samples, calculate PD and PDSLOPE
     thread::spawn(move || {
-        let mut lastamp = 0f32;
+        let mut last_sample = 0f32;
 
         let mut debug_writer = match output {
             Output::Debug => Some(BufWriter::new(File::create("debug-pd.csv").expect("create file"))),
@@ -303,9 +304,9 @@ fn main() {
                efficient and pretty good interpolation filter. */
 
             for sample in buf {
-                let slope = (sample - lastamp) / rf_to_baseband_sample_ratio as f32;
+                let slope = (sample - last_sample) / rf_to_baseband_sample_ratio as f32;
 
-                let pd = lastamp * modulation_index * INT32_MAX_AS_FLOAT;
+                let pd = last_sample * modulation_index * INT32_MAX_AS_FLOAT;
 
                 const MIN_VAL: f32 = std::i32::MIN as f32;
                 const MAX_VAL: f32 = std::i32::MAX as f32;
@@ -326,7 +327,7 @@ fn main() {
 
                 pd_buf.push((pd as i32, pdslope as i32));
 
-                lastamp = sample;
+                last_sample = sample;
             }
 
             if let Err(_) = pd_tx.send(pd_buf) {