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/*
* Bluetooth low-complexity, subband codec (SBC) library
* Copyright (C) 2004-2010 Marcel Holtmann <marcel@holtmann.org>
* Copyright (C) 2008-2010 Nokia Corporation
* Copyright (C) 2012-2013 Intel Corporation
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdbool.h>
#include <stdint.h>
#include <string.h>
#include <libgen.h>
#if __BYTE_ORDER == __LITTLE_ENDIAN
struct 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_ENDIAN
struct 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"
#endif
static int calc_frame_len(struct sbc_frame_hdr *hdr, int nrof_blocks)
{
int tmp, nrof_subbands;
nrof_subbands = (hdr->subbands + 1) * 4;
switch (hdr->channel_mode) {
case 0x00:
nrof_subbands /= 2;
tmp = nrof_blocks * hdr->bitpool;
break;
case 0x01:
tmp = nrof_blocks * hdr->bitpool * 2;
break;
case 0x02:
tmp = nrof_blocks * hdr->bitpool;
break;
case 0x03:
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_blocks)
{
int nrof_subbands;
double f;
nrof_subbands = (hdr->subbands + 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, nrof_blocks) + 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 32
static 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, method;
int n, p1, p2, fd, size, num;
bool msbc;
ssize_t len;
unsigned int count;
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));
if (len == sizeof(hdr) && hdr.syncword == 0x9c) {
msbc = false;
} else if (len == sizeof(hdr) && hdr.syncword == 0xad) {
msbc = true;
} else {
fprintf(stderr, "Not a SBC audio file\n");
return -1;
}
if (msbc) {
hdr.subbands = 1; /* 8 */
hdr.sampling_frequency = 0x00; /* 16000 */
hdr.allocation_method = 0; /* Loudness */
hdr.bitpool = 26;
hdr.channel_mode = 0x00; /* Mono */
blocks = 15;
} else {
blocks = (hdr.blocks + 1) * 4;
}
subbands = (hdr.subbands + 1) * 4;
freq = hdr.sampling_frequency;
method = hdr.allocation_method;
count = calc_frame_len(&hdr, blocks);
bitpool[0] = hdr.bitpool;
frame_len[0] = count + 4;
for (n = 1; n < SIZE; n++) {
bitpool[n] = 0;
frame_len[n] = 0;
}
if (lseek(fd, 0, SEEK_SET) < 0) {
num = 1;
rate = calc_bit_rate(&hdr, blocks);
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 ((size_t) len < sizeof(hdr) || !(hdr.syncword == 0x9c ||
hdr.syncword == 0xad)) {
fprintf(stderr, "Corrupted SBC stream "
"(len %zd syncword 0x%02x)\n",
len, hdr.syncword);
break;
}
if (msbc) {
hdr.subbands = 1; /* 8 */
hdr.sampling_frequency = 0x00; /* 16000 */
hdr.allocation_method = 0; /* Loudness */
hdr.bitpool = 26;
hdr.channel_mode = 0x00; /* Mono */
}
count = calc_frame_len(&hdr, blocks);
len = count + 4;
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, blocks);
num++;
}
printf("mSBC\t\t\t%d\n", msbc);
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;
}
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