feat: add M4A/AAC support and update application version to dev43

source/m4a.c

@@ -0,0 +1,133 @@
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <3ds.h>
+
+#include "error.h"
+#include "m4a.h"
+#include "playback.h"
+
+/* TODO: Integrate proper AAC decoder library (libfaad2, fdk-aac, or minimp4) */
+/* For now, this is a stub implementation */
+
+static size_t*			buffSize;
+static uint32_t			rate = 44100;
+static uint8_t			channels = 2;
+
+static int initM4a(const char* file);
+static uint32_t rateM4a(void);
+static uint8_t channelM4a(void);
+static uint64_t decodeM4a(void* buffer);
+static void exitM4a(void);
+static size_t getFileSamplesM4a(void);
+
+/**
+ * Set decoder parameters for M4A/AAC.
+ *
+ * \param	decoder Structure to store parameters.
+ */
+void setM4a(struct decoder_fn* decoder)
+{
+	decoder->init = &initM4a;
+	decoder->rate = &rateM4a;
+	decoder->channels = &channelM4a;
+	buffSize = &(decoder->buffSize);
+	decoder->decode = &decodeM4a;
+	decoder->exit = &exitM4a;
+	decoder->getFileSamples = &getFileSamplesM4a;
+}
+
+/**
+ * Check if a file is an M4A/AAC/ALAC file.
+ *
+ * \param	file	File location.
+ * \return			0 on success, -1 on failure.
+ */
+int isM4a(const char* file)
+{
+	FILE* ftest = fopen(file, "rb");
+	uint32_t fileSig;
+	uint32_t ftypSig;
+	
+	if(ftest == NULL)
+		return -1;
+	
+	/* Read first 4 bytes (should be size of ftyp atom) */
+	if(fread(&fileSig, 4, 1, ftest) == 0)
+	{
+		fclose(ftest);
+		return -1;
+	}
+	
+	/* Read next 4 bytes (should be 'ftyp') */
+	if(fread(&ftypSig, 4, 1, ftest) == 0)
+	{
+		fclose(ftest);
+		return -1;
+	}
+	
+	fclose(ftest);
+	
+	/* Check for 'ftyp' signature (0x70797466 in little-endian) */
+	if(ftypSig == 0x70797466)
+		return 0;
+	
+	return -1;
+}
+
+static int initM4a(const char* file)
+{
+	(void)file;
+	
+	/* TODO: Initialize AAC decoder */
+	/* This requires:
+	 * 1. Parse MP4 container to find AAC audio track
+	 * 2. Extract decoder config (sample rate, channels, etc.)
+	 * 3. Initialize AAC decoder with config
+	 */
+	
+	/* Set default values for now */
+	rate = 44100;
+	channels = 2;
+	*buffSize = rate * channels * sizeof(int16_t);
+	
+	errno = FILE_NOT_SUPPORTED;
+	return -1;
+}
+
+static uint32_t rateM4a(void)
+{
+	return rate;
+}
+
+static uint8_t channelM4a(void)
+{
+	return channels;
+}
+
+static uint64_t decodeM4a(void* buffer)
+{
+	(void)buffer;
+	
+	/* TODO: Decode AAC frame */
+	/* This requires:
+	 * 1. Read next AAC frame from MP4 container
+	 * 2. Decode AAC frame to PCM samples
+	 * 3. Write PCM samples to buffer
+	 * 4. Return number of samples decoded
+	 */
+	
+	return 0;
+}
+
+static void exitM4a(void)
+{
+	/* TODO: Clean up AAC decoder */
+}
+
+static size_t getFileSamplesM4a(void)
+{
+	/* TODO: Calculate total samples from MP4 metadata */
+	return 0;
+}