/* * *  Bluetooth low-complexity, subband codec (SBC) library * *  Copyright (C) 2004-2007  Marcel Holtmann <marcel@holtmann.org> * * *  This program is free software; you can redistribute it and/or modify *  it under the terms of the GNU General Public License as published by *  the Free Software Foundation; either version 2 of the License, or *  (at your option) any later version. * *  This program is distributed in the hope that it will be useful, *  but WITHOUT ANY WARRANTY; without even the implied warranty of *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the *  GNU General Public License for more details. * *  You should have received a copy of the GNU General Public License *  along with this program; if not, write to the Free Software *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA * */#ifdef HAVE_CONFIG_H#include <config.h>#endif#include <stdio.h>#include <errno.h>#include <fcntl.h>#include <unistd.h>#include <stdlib.h>#include <stdint.h>#include <string.h>#include <libgen.h>#if __BYTE_ORDER == __LITTLE_ENDIANstruct sbc_frame_hdr {	uint8_t syncword:8;		/* Sync word */	uint8_t subbands:1;		/* Subbands */	uint8_t allocation_method:1;	/* Allocation method */	uint8_t channel_mode:2;		/* Channel mode */	uint8_t blocks:2;		/* Blocks */	uint8_t sampling_frequency:2;	/* Sampling frequency */	uint8_t bitpool:8;		/* Bitpool */	uint8_t crc_check:8;		/* CRC check */} __attribute__ ((packed));#elif __BYTE_ORDER == __BIG_ENDIANstruct sbc_frame_hdr {	uint8_t syncword:8;		/* Sync word */	uint8_t sampling_frequency:2;	/* Sampling frequency */	uint8_t blocks:2;		/* Blocks */	uint8_t channel_mode:2;		/* Channel mode */	uint8_t allocation_method:1;	/* Allocation method */	uint8_t subbands:1;		/* Subbands */	uint8_t bitpool:8;		/* Bitpool */	uint8_t crc_check:8;		/* CRC check */} __attribute__ ((packed));#else#error "Unknown byte order"#endifstatic int calc_frame_len(struct sbc_frame_hdr *hdr){	int tmp, nrof_subbands, nrof_blocks;	nrof_subbands = (hdr->subbands + 1) * 4;/*子帶數目4 /8*/	nrof_blocks = (hdr->blocks + 1) * 4;/*blocks number 4 /8/12/16*/	switch (hdr->channel_mode) {	case 0x00:/*MONO*/		nrof_subbands /= 2;		tmp = nrof_blocks * hdr->bitpool;		break;	case 0x01:/*DUAL_CHANNEL*/		tmp = nrof_blocks * hdr->bitpool * 2;		break;	case 0x02:/*STEREO*/		tmp = nrof_blocks * hdr->bitpool;		break;	case 0x03:/*JOIN_STEREO*/		tmp = nrof_blocks * hdr->bitpool + nrof_subbands;		break;	default:		return 0;	}	return (nrof_subbands + ((tmp + 7) / 8));}static double calc_bit_rate(struct sbc_frame_hdr *hdr){	int nrof_subbands, nrof_blocks;	double f;	nrof_subbands = (hdr->subbands + 1) * 4;	nrof_blocks = (hdr->blocks + 1) * 4;	switch (hdr->sampling_frequency) {	case 0:		f = 16;		break;	case 1:		f = 32;		break;	case 2:		f = 44.1;		break;	case 3:		f = 48;		break;	default:		return 0;	}	return ((8 * (calc_frame_len(hdr) + 4) * f) /			(nrof_subbands * nrof_blocks));}static char *freq2str(uint8_t freq){	switch (freq) {	case 0:		return "16 kHz";	case 1:		return "32 kHz";	case 2:		return "44.1 kHz";	case 3:		return "48 kHz";	default:		return "Unknown";	}}static char *mode2str(uint8_t mode){	switch (mode) {	case 0:		return "Mono";	case 1:		return "Dual Channel";	case 2:		return "Stereo";	case 3:		return "Joint Stereo";	default:		return "Unknown";	}}static ssize_t __read(int fd, void *buf, size_t count){	ssize_t len, pos = 0;	while (count > 0) {		len = read(fd, buf + pos, count);		if (len <= 0)			return len;		count -= len;		pos   += len;	}	return pos;}#define SIZE 32static int analyze_file(char *filename){	struct sbc_frame_hdr hdr;	unsigned char buf[64];	double rate;	int bitpool[SIZE], frame_len[SIZE];	int subbands, blocks, freq, mode, method;	int n, p1, p2, fd, len, size, count, num;	if (strcmp(filename, "-")) {		printf("Filename\t\t%s\n", basename(filename));		fd = open(filename, O_RDONLY);		if (fd < 0) {			perror("Can't open file");			return -1;		}	} else		fd = fileno(stdin);	len = __read(fd, &hdr, sizeof(hdr));/*READ THE HEAD OF THE FILE*/	if (len != sizeof(hdr) || hdr.syncword != 0x9c ) {		fprintf(stderr, "Not a SBC audio file\n");		return -1;	}    /*GET THE PARAMETER*/	subbands = (hdr.subbands + 1) * 4;	blocks = (hdr.blocks + 1) * 4;	freq = hdr.sampling_frequency;	mode = hdr.channel_mode;	method = hdr.allocation_method;	count = calc_frame_len(&hdr);	bitpool[0] = hdr.bitpool;	frame_len[0] = count + 4;	for (n = 1; n < SIZE; n++) {		bitpool[n] = 0;		frame_len[n] = 0;	}    /*count is frame len*/	if (lseek(fd, 0, SEEK_SET) < 0) {		num = 1;		rate = calc_bit_rate(&hdr);		while (count) {			size = count > sizeof(buf) ? sizeof(buf) : count;			len = __read(fd, buf, size);			if (len < 0)				break;			count -= len;		}	} else {		num = 0;		rate = 0;	}	while (1) {		len = __read(fd, &hdr, sizeof(hdr));		if (len < 0) {			fprintf(stderr, "Unable to read frame header"					" (error %d)\n", errno);			break;		}		if (len == 0)			break;		if (len < sizeof(hdr) || hdr.syncword != 0x9c) {			fprintf(stderr, "Corrupted SBC stream "					"(len %d syncword 0x%02x)\n",					len, hdr.syncword);			break;		}		count = calc_frame_len(&hdr);		len = count + 4;/*add the header len*/		p1 = -1;		p2 = -1;		for (n = 0; n < SIZE; n++) {			if (p1 < 0 && (bitpool[n] == 0 || bitpool[n] == hdr.bitpool))				p1 = n;			if (p2 < 0 && (frame_len[n] == 0 || frame_len[n] == len))				p2 = n;		}		if (p1 >= 0)			bitpool[p1] = hdr.bitpool;		if (p2 >= 0)			frame_len[p2] = len;		while (count) {			size = count > sizeof(buf) ? sizeof(buf) : count;			len = __read(fd, buf, size);			if (len != size) {				fprintf(stderr, "Unable to read frame data "						"(error %d)\n", errno);				break;			}			count -= len;		}		rate += calc_bit_rate(&hdr);		num++;	}	printf("Subbands\t\t%d\n", subbands);	printf("Block length\t\t%d\n", blocks);	printf("Sampling frequency\t%s\n", freq2str(freq));	printf("Channel mode\t\t%s\n", mode2str(hdr.channel_mode));	printf("Allocation method\t%s\n", method ? "SNR" : "Loudness");	printf("Bitpool\t\t\t%d", bitpool[0]);	for (n = 1; n < SIZE; n++)		if (bitpool[n] > 0)			printf(", %d", bitpool[n]);	printf("\n");	printf("Number of frames\t%d\n", num);	printf("Frame length\t\t%d", frame_len[0]);	for (n = 1; n < SIZE; n++)		if (frame_len[n] > 0)			printf(", %d", frame_len[n]);	printf(" Bytes\n");	if (num > 0)		printf("Bit rate\t\t%.3f kbps\n", rate / num);	if (fd > fileno(stderr))		close(fd);	printf("\n");	return 0;}int main(int argc, char *argv[]){	int i;	if (argc < 2) {		fprintf(stderr, "Usage: sbcinfo <file>\n");		exit(1);	}	for (i = 0; i < argc - 1; i++)		if (analyze_file(argv[i + 1]) < 0)			exit(1);	return 0;}