Add comments and README

README.md

@@ -0,0 +1,14 @@
+Make run to compile and run
+```
+make run
+```
+I'm using the whole new pipewire + wireplumber audio stack, which has
+compatibility with pulse audio.
+
+Seems like there is ``SDL_AUDIODRIVER=alsa`` environment variable that SDL can
+use. I don't think my code works with this enabled.
+
+[Maybe related GitHub issue](https://github.com/libsdl-org/SDL/issues/9706)
+
+I'm using SDL2 version 2.28.5. Downgrading from 2.30.7 seems to make it work a
+bit better, but still not consistent.

example-test-code/README.md

@@ -0,0 +1 @@
+Some code here is from ChatGPT

main.c

@@ -5,7 +5,9 @@
 #include <stdio.h>
 
 #include "log.h"
-
+/*
+ * INFO: I will mark places to look at with INFO:
+ */
 const int SCREEN_WIDTH = 640;
 const int SCREEN_HEIGHT = 480;
 
@@ -52,7 +54,7 @@ int text_texture_load(text_texture* text_texture, char* string);
 int text_texture_render(text_texture* text_texture, int x, int y);
 int text_texture_free(text_texture* text_texture);
 /*
- * Audio
+ * Audio INFO: audio related declarations and callback here.
  */
 int num_devices = 0;
 
@@ -107,23 +109,24 @@ int main(int argc, char* argv[])
 	text_texture_load(&state_text_texture, char_buffer);
 
 	SDL_Event event;
-	int running = 1;
+	while (1) {
-	while (running) {
 		while (SDL_PollEvent(&event)) {
 			SDL_Keycode keysym = event.key.keysym.sym;
 			switch (event.type) {
 
 			case SDL_QUIT:
-				running = 0;
+				goto cleanup;
 				break;
 
 			case SDL_KEYDOWN:
+				// INFO: main state logic here.
 				handle_input(&event, &state);
 				break;
 
 			}
 		}
 
+		// INFO: more state logic here. I check the buffer write position here
 		handle_task(&state);
 
 		sprintf(char_buffer, default_fmt, state.device_index);
@@ -153,6 +156,9 @@ int main(int argc, char* argv[])
 		SDL_RenderPresent(renderer);
 	}
 
+cleanup:
+	SDL_CloseAudioDevice(state.recording_device_id);
+	SDL_CloseAudioDevice(state.playback_device_id);
 	text_texture_free(&display_text_texture);
 	for (int i = 0; i < num_devices; i++) {
 		text_texture_free(&device_textures[i]);
@@ -166,17 +172,24 @@ void handle_input(SDL_Event* event, state* state)
 {
 	SDL_Keycode keysym = event->key.keysym.sym;
 	switch (state->application_state) {
-
+	// INFO: init of recording audio device here
 	case SELECTING_DEVICE:
 		switch (keysym) {
 		case SDLK_y:
 		case SDLK_RETURN:
+			// INFO: init audio device here and below
+			// Here it initialises everytime you press enter or y, and
+			// unpauses device immediately. Seems to work mor consistently
 			SDL_CloseAudioDevice(state->recording_device_id);
-			state->recording_device_id = audio_recording_init(state->device_index, NULL);
+			state->recording_device_id =
+			    audio_recording_init(state->device_index, NULL);
+
 			if (state->device_index == -1 || !state->recording_device_id) break;
 			recording_buffer_position = 0;
+			// INFO: calling this should unpause the device and start calling the callback
 			SDL_PauseAudioDevice(state->recording_device_id, 0);
 			/*SDL_UnlockAudioDevice(state->recording_device_id);*/
+			// INFO: state change looks like this here
 			state->application_state = RECORDING;
 			break;
 		case SDLK_ESCAPE:
@@ -188,6 +201,12 @@ void handle_input(SDL_Event* event, state* state)
 		if (device_index_new == -1) break;
 		if (state->device_index != -1 && device_index_new == -1) break;
 		state->device_index = device_index_new;
+		// INFO: inititialising here seems to be less consistent. When I
+		// spam enter or y after initialising here, Sometimes I see
+		// callback being called sometimes not.
+		/*SDL_CloseAudioDevice(state->recording_device_id);*/
+		/*state->recording_device_id = audio_recording_init(state->device_index, NULL);*/
+
 		break;
 
 	case RECORDING:
@@ -203,7 +222,7 @@ void handle_input(SDL_Event* event, state* state)
 			break;
 		}
 		break;
-
+	// INFO: init of playback audio device here. Can't seem to get it to play / call callback
 	case RECORDED:
 		switch (keysym) {
 		case SDLK_y:
@@ -243,6 +262,7 @@ void handle_task(state* state)
 		break;
 
 	case RECORDING:
+		// INFO: check buffer position here and stop if reaces the end
 		SDL_LockAudioDevice(state->recording_device_id);
 		/*printf("buf pos: %u\n", recording_buffer_position);*/
 		if (recording_buffer_position >= recording_buffer_position_max) {
@@ -259,6 +279,7 @@ void handle_task(state* state)
 		break;
 
 	case PLAYBACK:
+		// INFO:
 		SDL_LockAudioDevice(state->playback_device_id);
 		if (recording_buffer_position >= recording_buffer_position_max) {
 			SDL_UnlockAudioDevice(state->playback_device_id);
@@ -421,9 +442,11 @@ int text_texture_free(text_texture* text_texture)
 	SDL_DestroyTexture(text_texture->texture);
 	return 1;
 }
-
+// INFO: device init here
+// Most of the audio stuff I copied from an example
 SDL_AudioDeviceID audio_recording_init(int index, void* userdata)
 {
+	// INFO: audio spec and callback
 	SDL_zero(recording_spec);
 	recording_spec.freq = 44100;
 	recording_spec.format = AUDIO_F32;
@@ -441,6 +464,7 @@ SDL_AudioDeviceID audio_recording_init(int index, void* userdata)
 
 	unsigned int bytes_per_sample = received_recording_spec.channels * (SDL_AUDIO_BITSIZE(received_recording_spec.format)/8);
 	unsigned int bytes_per_second = received_recording_spec.freq * bytes_per_sample;
+	// INFO: I just copied example where they allocated 1 second worth of buffer so it doesn't die
 	recording_buffer_size = RECORDING_BUFFER_SECONDS * bytes_per_second;
 	recording_buffer_position_max = MAX_RECORDING_SECONDS * bytes_per_second;
 
@@ -449,14 +473,14 @@ SDL_AudioDeviceID audio_recording_init(int index, void* userdata)
 
 	return device_id;
 }
-
+// INFO:
 SDL_AudioDeviceID audio_playback_init(void* userdata)
 {
 	if (!recording_buffer) {
 		printf("Audio buffer not initialized");
 		return 0;
 	}
-
+	// INFO: audio spec and callback
 	SDL_zero(playback_spec);
 	playback_spec.freq = 44100;
 	playback_spec.format = AUDIO_F32;
@@ -488,7 +512,7 @@ void audio_buffer_destroy()
 	recording_buffer_size = 0;
 	recording_buffer_position = 0;
 }
-
+// INFO: callback here
 void audio_recording_callback(void* userdata, Uint8* stream, int len)
 {
 	memcpy(&recording_buffer[recording_buffer_position], stream, len);
@@ -498,7 +522,7 @@ void audio_recording_callback(void* userdata, Uint8* stream, int len)
 	printf(string, "Record pos: %u %u\n", recording_buffer_position, len);
 	log_message(LOG_INFO, string);
 }
-
+// INFO:
 void audio_playback_callback(void* userdata, Uint8* stream, int len)
 {
 	memcpy(stream, &recording_buffer[recording_buffer_position], len);