add a version with rds

stereo_coder.c

@@ -9,13 +9,12 @@
 #define OUTPUT_DEVICE "alsa_output.platform-soc_sound.stereo-fallback"
 #define BUFFER_SIZE 512
 
-#define MONO_VOLUME 0.5f
-#define PILOT_VOLUME 0.025f
-#define STEREO_VOLUME 0.275f
-
+#define MONO_VOLUME 0.5f // L+R Signal
+#define PILOT_VOLUME 0.025f // 19 KHz Pilot
+#define STEREO_VOLUME 0.275f // L-R signal
 
 #define TWO_BUFFER_SIZE (BUFFER_SIZE*2) // Don't touch this
-volatile int to_run = 1;
+volatile sig_atomic_t to_run = 1;
 
 const float format_scale = 1.0f / 32768.0f;
 void stereo_s16le_to_float(const int16_t *input, float *left, float *right, size_t num_samples) {
@@ -66,12 +65,12 @@ int main() {
     const float STEREO_FREQ = 38000.0f;
 
     // Define formats and buffer atributes
-    pa_sample_spec input_format = {
+    pa_sample_spec stereo_format = {
         .format = PA_SAMPLE_S16LE,
         .channels = 2,
         .rate = SAMPLE_RATE
     };
-    pa_sample_spec output_format = {
+    pa_sample_spec mono_format = {
         .format = PA_SAMPLE_S16LE,
         .channels = 1,
         .rate = SAMPLE_RATE
@@ -95,7 +94,7 @@ int main() {
         PA_STREAM_RECORD,
         INPUT_DEVICE,
         "Audio Input",
-        &input_format,
+        &stereo_format,
         NULL,
         &input_buffer_atr,
         NULL
@@ -113,7 +112,7 @@ int main() {
         PA_STREAM_PLAYBACK,
         OUTPUT_DEVICE,
         "MPX",
-        &output_format,
+        &mono_format,
         NULL,
         &output_buffer_atr,
         NULL
@@ -148,7 +147,7 @@ int main() {
 
             float mono = (left[i] + right[i]) / 2.0f;
             float stereo = (left[i] - right[i]) / 2.0f;
-            
+
             mpx[i] = mono*MONO_VOLUME +
                      (stereo * stereo_carrier)*STEREO_VOLUME +
                      (pilot * PILOT_VOLUME);