amrnb2pcm.c

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/mman.h>

#ifdef __cplusplus
extern "C"{
#endif
#include <opencore-amrnb/interf_dec.h>
#ifdef __cplusplus
}
#endif


#define ALOGE(...) printf(__VA_ARGS__);printf("\n")

#define AMR_MAGIC_NUMBER "#!AMR\n"

// load_file to memory, free memory by caller
unsigned char *load_file(const char *path, int *data_size)
{
	FILE *fd;
	struct stat sb;
	unsigned char *buffer;
	size_t size;
	size_t n;

	fd = fopen(path, "rb");
	if (!fd) {
		ALOGE("fopen: %s", strerror(errno));
		//perror(path);
		//exit(EXIT_FAILURE);
		return NULL;
	}

	if (stat(path, &sb)) {
		ALOGE("stat: %s", strerror(errno));
		//perror(path);
		// exit(EXIT_FAILURE);
		return NULL;
	}
	size = sb.st_size;

	buffer = (unsigned char*)malloc(size);
	if (!buffer) {
		ALOGE("Unable to allocate %lld bytes\n",
			(long long)size);
		//exit(EXIT_FAILURE);
		return NULL;
	}

	n = fread(buffer, 1, size, fd);
	if (n != size) {
		ALOGE("fread: %s", strerror(errno));
		//exit(EXIT_FAILURE);
		free(buffer);
		return NULL;
	}

	fclose(fd);

	*data_size = size;
	return buffer;
}

int main(int argc, char** argv)
{
	if (argc != 2){
		printf("usage: %s file.mp3\n", argv[0]);
		return 0;
	}

	int file_length = 0;
	char* file_buf = (char*)load_file(argv[1], &file_length);
	if (! file_buf){
		ALOGE("load_file %s error", argv[1]);
		return 0;
	} else {
		if (strncmp(file_buf, AMR_MAGIC_NUMBER, 
					strlen(AMR_MAGIC_NUMBER) ) ) {
       ALOGE("Invalid magic number: %s", argv[1]);
	   free(file_buf);
		return 0;
		}
	}

	int amrnb_len = file_length - strlen(AMR_MAGIC_NUMBER);
    char* amrnb_buf = file_buf + strlen(AMR_MAGIC_NUMBER);

	void* amr = NULL;
    short block_size[16]={ 12, 13, 15, 17, 19, 20, 26, 31, 5, 0, 0, 0, 0, 0, 0, 0 };
	ALOGE("AMR-NB Data lengeth: %d", amrnb_len);
    /* init decoder */
    amr = Decoder_Interface_init();
    if(!amr){
        ALOGE("Decoder_Interface_init");
		free(file_buf);
		return 0;
    }

	int16_t outbuffer[160];
	uint8_t buffer[32];
	int size = 0, j = 0;
    for(j = 0; j < amrnb_len; j++){
		/* Find the packet size */
		ALOGE("find the packet size : %d", (amrnb_buf[j] >> 3) & 0x0f);
		size = block_size[(amrnb_buf[j] >> 3) & 0x0f];
		memcpy(buffer, amrnb_buf + j, size + 1);
		j += size;

		ALOGE("packet size: %d", size);

		/* Decode the packet */
		Decoder_Interface_Decode(amr, buffer, outbuffer, 0);

		/* Convert to little endian and write to wav */
		// TODO save littleendian (size:320) to pcm
    }
    Decoder_Interface_exit(amr);

	ALOGE("AMR-NB Data Decode finished");
    free(file_buf);
    return 0;
}