switch-examples/audio/echo/source/main.c

#include <string.h>
#include <stdio.h>
#include <malloc.h>
#include <math.h>

#include <switch.h>

// Example for audio capture and playback.
// This example continuously records audio data from the default input device (see libnx audin.h),
// and sends it to the default audio output device (see libnx audout.h).

#define SAMPLERATE 48000
#define CHANNELCOUNT 2
#define FRAMERATE (1000 / 30)
#define SAMPLECOUNT (SAMPLERATE / FRAMERATE)
#define BYTESPERSAMPLE 2

int main(int argc, char **argv)
{
	Result rc = 0;
	
	gfxInitDefault();

	// Initialize console. Using NULL as the second argument tells the console library to use the internal console structure as current one.
	consoleInit(NULL);
	
	AudioInBuffer audin_buf;
	AudioOutBuffer audout_buf;
	AudioInBuffer *released_in_buffer;
	AudioOutBuffer *released_out_buffer;
	u32 released_in_count;
	u32 released_out_count;
	
	// Make sure the sample buffer size is aligned to 0x1000 bytes.
	u32 data_size = (SAMPLECOUNT * CHANNELCOUNT * BYTESPERSAMPLE);
	u32 buffer_size = (data_size + 0xfff) & ~0xfff;
	
	// Allocate the buffers.
	u8* in_buf_data = memalign(0x1000, buffer_size);
	u8* out_buf_data = memalign(0x1000, buffer_size);

	// Ensure buffers were properly allocated.
	if ((in_buf_data == NULL) || (out_buf_data == NULL))
	{
		rc = MAKERESULT(Module_Libnx, LibnxError_OutOfMemory);
		printf("Failed to allocate sample data buffers\n");
	}
	
	if (R_SUCCEEDED(rc))
	{
		memset(in_buf_data, 0, buffer_size);
		memset(out_buf_data, 0, buffer_size);
	}
	
	if (R_SUCCEEDED(rc))
	{
		// Initialize the default audio input device.
		rc = audinInitialize();
		printf("audinInitialize() returned 0x%x\n", rc);
	}
	
	if (R_SUCCEEDED(rc))
	{
		// Initialize the default audio output device.
		rc = audoutInitialize();
		printf("audoutInitialize() returned 0x%x\n", rc);
	}
	
	if (R_SUCCEEDED(rc))
	{
		// Start audio capture.
		rc = audinStartAudioIn();
		printf("audinStartAudioIn() returned 0x%x\n", rc);
	}
	
	if (R_SUCCEEDED(rc))
	{
		// Start audio playback.
		rc = audoutStartAudioOut();
		printf("audoutStartAudioOut() returned 0x%x\n", rc);
	}
	
	// Prepare the input buffer.
	audin_buf.next = NULL;
	audin_buf.buffer = in_buf_data;
	audin_buf.buffer_size = buffer_size;
	audin_buf.data_size = data_size;
	audin_buf.data_offset = 0;
	
	// Prepare the output buffer.
	audout_buf.next = NULL;
	audout_buf.buffer = out_buf_data;
	audout_buf.buffer_size = buffer_size;
	audout_buf.data_size = data_size;
	audout_buf.data_offset = 0;
	
	// Prepare pointers and counters for released buffers.
	released_in_buffer = NULL;
	released_out_buffer = NULL;
	released_in_count = 0;
	released_out_count = 0;
	
	// Append the initial input buffer.
	rc = audinAppendAudioInBuffer(&audin_buf);
	printf("audinAppendAudioInBuffer() returned 0x%x\n", rc);
	
	// Append the initial output buffer.
	rc = audoutAppendAudioOutBuffer(&audout_buf);
	printf("audoutAppendAudioOutBuffer() returned 0x%x\n", rc);

	while (appletMainLoop())
	{
		//Scan all the inputs. This should be done once for each frame
		hidScanInput();

		//hidKeysDown returns information about which buttons have been just pressed (and they weren't in the previous frame)
		u32 kDown = hidKeysDown(CONTROLLER_P1_AUTO);

		if (kDown & KEY_PLUS) break; // break in order to return to hbmenu
		
		// Wait for audio capture and playback to finish.
		audinWaitCaptureFinish(&released_in_buffer, &released_in_count, U64_MAX);
		audoutWaitPlayFinish(&released_out_buffer, &released_out_count, U64_MAX);
		
		// Copy the captured audio data into the playback buffer.
		if ((released_in_buffer != NULL) && (released_out_buffer != NULL))
			memcpy(released_out_buffer->buffer, released_in_buffer->buffer, released_in_buffer->data_size);
		
		// Append the released buffers again.
		audinAppendAudioInBuffer(released_in_buffer);
		audoutAppendAudioOutBuffer(released_out_buffer);
		
		gfxFlushBuffers();
		gfxSwapBuffers();
		gfxWaitForVsync();
	}
	
	// Stop audio capture.
	rc = audinStopAudioIn();
	printf("audinStopAudioIn() returned 0x%x\n", rc);
	
	// Stop audio playback.
	rc = audoutStopAudioOut();
	printf("audoutStopAudioOut() returned 0x%x\n", rc);

	// Terminate the default audio devices.
	audinExit();
	audoutExit();
	
	gfxExit();
	return 0;
}