add alsa output to STCode

.vscode/.server-controller-port.log

@@ -1,5 +1,5 @@
 {
   "port": 13452,
-  "time": 1737621156918,
+  "time": 1737734479782,
   "version": "0.0.3"
 }

.vscode/settings.json

@@ -12,6 +12,10 @@
         "options.h": "c",
         "random": "c",
         "__locale": "c",
-        "complex": "c"
+        "complex": "c",
+        "stdbool.h": "c",
+        "format": "c",
+        "ios": "c",
+        "stdint.h": "c"
     }
 }

README.md

@@ -16,6 +16,8 @@ As far as i've tested it (29-31 december) it's been fine but after a fix it was
 Also i'd recommend to use the SSB version because it's more spectrum effiecent
 but SSB has slightly more cpu usage
 
+This supports alsa output
+
 # PSTCode
 This is a yet another version of a Stereo encoder, however for the OIRT band which is in use in Russia, Belarus and other countries
 

src/stereo_coder.c

@@ -1,6 +1,4 @@
 #include <stdio.h>
-#include <pulse/simple.h>
-#include <pulse/error.h>
 #include <stdlib.h>
 #include <math.h>
 #include <stdint.h>
@@ -10,7 +8,9 @@
 #include "options.h"
 
 //#define SSB
+#ifdef SSB
 //#define USB
+#endif
 
 #include "../lib/constants.h"
 #include "../lib/oscillator.h"
@@ -23,9 +23,16 @@
 
 #define INPUT_DEVICE "real_real_tx_audio_input.monitor"
 #define OUTPUT_DEVICE "alsa_output.platform-soc_sound.stereo-fallback"
+#define ALSA_OUTPUT // Output, not input or both
 #define BUFFER_SIZE 512
 #define CLIPPER_THRESHOLD 0.525 // Adjust this as needed
 
+#include <pulse/simple.h>
+#include <pulse/error.h>
+#ifdef ALSA_OUTPUT
+#include <alsa/asoundlib.h>
+#endif
+
 #define MONO_VOLUME 0.45f // L+R Signal
 #define PILOT_VOLUME 0.09f // 19 KHz Pilot
 #define STEREO_VOLUME 0.45f // L-R signal possibly can be set to .9 because im not sure if usb will be 2 times stronger than dsb-sc
@@ -88,6 +95,8 @@ int main() {
 	    .prebuf = buffer_prebuf
     };
 
+    int open_pulse_error;
+
     printf("Connecting to input device... (%s)\n", INPUT_DEVICE);
 
     pa_simple *input_device = pa_simple_new(
@@ -99,15 +108,16 @@ int main() {
         &stereo_format,
         NULL,
         &input_buffer_atr,
-        NULL
+        &open_pulse_error
     );
     if (!input_device) {
-        fprintf(stderr, "Error: cannot open input device.\n");
+        fprintf(stderr, "Error: cannot open input device: %s\n", pa_strerror(open_pulse_error));
         return 1;
     }
 
     printf("Connecting to output device... (%s)\n", OUTPUT_DEVICE);
 
+    #ifndef ALSA_OUTPUT
     pa_simple *output_device = pa_simple_new(
         NULL,
         "StereoEncoder",
@@ -117,13 +127,40 @@ int main() {
         &mono_format,
         NULL,
         &output_buffer_atr,
-        NULL
+        &open_pulse_error
     );
     if (!output_device) {
-        fprintf(stderr, "Error: cannot open output device.\n");
+        fprintf(stderr, "Error: cannot open output device: %s\n", pa_strerror(open_pulse_error));
         pa_simple_free(input_device);
         return 1;
     }
+    #else
+    snd_pcm_hw_params_t *output_params;
+    snd_pcm_t *output_handle;
+    int output_error = snd_pcm_open(&output_handle, OUTPUT_DEVICE, SND_PCM_STREAM_PLAYBACK, 0);
+    if(output_error < 0) {
+        fprintf(stderr, "Error: cannot open output device: %s\n", snd_strerror(output_error));
+        pa_simple_free(input_device);
+        return 1;
+    }
+    snd_pcm_hw_params_malloc(&output_params);
+    snd_pcm_hw_params_any(output_handle, output_params);
+    snd_pcm_hw_params_set_access(output_handle, output_params, SND_PCM_ACCESS_RW_INTERLEAVED);
+    snd_pcm_hw_params_set_format(output_handle, output_params, SND_PCM_FORMAT_FLOAT); // Same as pulse's Float32NE
+    snd_pcm_hw_params_set_channels(output_handle, output_params, 1);
+    unsigned int rate = SAMPLE_RATE;
+    int dir;
+    snd_pcm_hw_params_set_rate_near(output_handle, output_params, &rate, &dir);
+    snd_pcm_uframes_t frames = BUFFER_SIZE;
+    snd_pcm_hw_params_set_period_size_near(output_handle, output_params, &frames, &dir); // i don't have a clue why like this
+    output_error = snd_pcm_hw_params(output_handle, output_params);
+    if(output_error < 0) {
+        fprintf(stderr, "Error: cannot open output device: %s\n", snd_strerror(output_error));
+        snd_pcm_close(output_handle);
+        pa_simple_free(input_device);
+        return 1;
+    }
+    #endif
 
     Oscillator pilot_osc;
     init_oscillator(&pilot_osc, 19000.0, SAMPLE_RATE); // Pilot, it's there to indicate stereo and as a refrence signal with the stereo carrier
@@ -216,15 +253,24 @@ int main() {
 #endif
         }
 
+#ifndef ALSA_OUTPUT
         if (pa_simple_write(output_device, mpx, sizeof(mpx), &pulse_error) < 0) {
             fprintf(stderr, "Error writing to output device: %s\n", pa_strerror(pulse_error));
             to_run = 0;
             break;
         }
+#else
+        snd_pcm_writei(output_handle, mpx, sizeof(mpx));
+#endif
     }
     printf("Cleaning up...\n");
     pa_simple_free(input_device);
+    #ifndef ALSA_OUTPUT
     pa_simple_free(output_device);
+    #else
+    snd_pcm_drain(output_handle);
+    snd_pcm_free(output_handle);
+    #endif
 #ifdef SSB
     exit_hilbert(&hilbert);
     exit_delay_line(&monoDelay);

wip/tv_encoder.c

@@ -0,0 +1,48 @@
+// This will encode a black and white TV signal using a luminance value, how does it work?
+/*
+    It encodes the luminance into negative values, so totally white pixel should output -1, a black one should be 0
+    
+    Every new line it sends a 0.5, every frame it is a 1.0
+*/
+
+#include "../lib/fm_modulator.h"
+
+unsigned int rgb_to_luminance(unsigned int r, unsigned int g, unsigned int b) {
+    return (unsigned int)(0.299 * r + 0.587 * g + 0.114 * b);
+}
+
+typedef struct {
+    int line;
+    int pixel;
+    int lines;
+    int pixels;
+} TVEncoder;
+
+void init_tv_modulator(TVEncoder* tv, int lines, int pixels) {
+    tv->pixels = pixels;
+    tv->lines = lines;
+    tv->line = 0;
+    tv->pixel = 0;
+}
+
+float tv_encode(TVEncoder* tv, float luminance) {
+    float normalized_luminance = luminance / 255.0f;  // Normalize luminance to [0, 1]
+
+    if (tv->line < tv->lines) {
+        if (tv->pixel < tv->pixels) {
+            // Process pixel within the current line
+            tv->pixel++;
+            return -normalized_luminance;
+        } else {
+            // End of line: reset pixel counter and move to the next line
+            tv->pixel = 0;
+            tv->line++;
+            return 0.5f;
+        }
+    } else {
+        // End of frame: reset frame counters
+        tv->line = 0;
+        tv->pixel = 0;
+        return 1.0f;
+    }
+}