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bluez/alsa/sbc.c
Marcel Holtmann f2e48c44a7 Update copyright information
2006-01-03 13:28:56 +00:00

1369 lines
40 KiB
C
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/*
*
* Bluetooth low-complexity, subband codec (SBC) library
*
* Copyright (C) 2004-2006 Marcel Holtmann <marcel@holtmann.org>
* Copyright (C) 2004-2005 Henryk Ploetz <henryk@ploetzli.ch>
*
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; 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 <errno.h>
#include <malloc.h>
#include <string.h>
#include <sys/types.h>
#include "sbc.h"
/* A2DP specification: Appendix B, page 69 */
static const int sbc_offset4[4][4] = {
{ -1, 0, 0, 0 },
{ -2, 0, 0, 1 },
{ -2, 0, 0, 1 },
{ -2, 0, 0, 1 }
};
/* A2DP specification: Appendix B, page 69 */
static const int sbc_offset8[4][8] = {
{ -2, 0, 0, 0, 0, 0, 0, 1 },
{ -3, 0, 0, 0, 0, 0, 1, 2 },
{ -4, 0, 0, 0, 0, 0, 1, 2 },
{ -4, 0, 0, 0, 0, 0, 1, 2 }
};
/* A2DP specification: Appendix B, page 70 */
static const float sbc_proto_4_40[40] = {
0.00000000E+00, 5.36548976E-04, 1.49188357E-03, 2.73370904E-03,
3.83720193E-03, 3.89205149E-03, 1.86581691E-03, -3.06012286E-03,
1.09137620E-02, 2.04385087E-02, 2.88757392E-02, 3.21939290E-02,
2.58767811E-02, 6.13245186E-03, -2.88217274E-02, -7.76463494E-02,
1.35593274E-01, 1.94987841E-01, 2.46636662E-01, 2.81828203E-01,
2.94315332E-01, 2.81828203E-01, 2.46636662E-01, 1.94987841E-01,
-1.35593274E-01, -7.76463494E-02, -2.88217274E-02, 6.13245186E-03,
2.58767811E-02, 3.21939290E-02, 2.88757392E-02, 2.04385087E-02,
-1.09137620E-02, -3.06012286E-03, 1.86581691E-03, 3.89205149E-03,
3.83720193E-03, 2.73370904E-03, 1.49188357E-03, 5.36548976E-04
};
/* A2DP specification: Appendix B, page 70 */
static const float sbc_proto_8_80[80] = {
0.00000000E+00, 1.56575398E-04, 3.43256425E-04, 5.54620202E-04,
8.23919506E-04, 1.13992507E-03, 1.47640169E-03, 1.78371725E-03,
2.01182542E-03, 2.10371989E-03, 1.99454554E-03, 1.61656283E-03,
9.02154502E-04, -1.78805361E-04, -1.64973098E-03, -3.49717454E-03,
5.65949473E-03, 8.02941163E-03, 1.04584443E-02, 1.27472335E-02,
1.46525263E-02, 1.59045603E-02, 1.62208471E-02, 1.53184106E-02,
1.29371806E-02, 8.85757540E-03, 2.92408442E-03, -4.91578024E-03,
-1.46404076E-02, -2.61098752E-02, -3.90751381E-02, -5.31873032E-02,
6.79989431E-02, 8.29847578E-02, 9.75753918E-02, 1.11196689E-01,
1.23264548E-01, 1.33264415E-01, 1.40753505E-01, 1.45389847E-01,
1.46955068E-01, 1.45389847E-01, 1.40753505E-01, 1.33264415E-01,
1.23264548E-01, 1.11196689E-01, 9.75753918E-02, 8.29847578E-02,
-6.79989431E-02, -5.31873032E-02, -3.90751381E-02, -2.61098752E-02,
-1.46404076E-02, -4.91578024E-03, 2.92408442E-03, 8.85757540E-03,
1.29371806E-02, 1.53184106E-02, 1.62208471E-02, 1.59045603E-02,
1.46525263E-02, 1.27472335E-02, 1.04584443E-02, 8.02941163E-03,
-5.65949473E-03, -3.49717454E-03, -1.64973098E-03, -1.78805361E-04,
9.02154502E-04, 1.61656283E-03, 1.99454554E-03, 2.10371989E-03,
2.01182542E-03, 1.78371725E-03, 1.47640169E-03, 1.13992507E-03,
8.23919506E-04, 5.54620202E-04, 3.43256425E-04, 1.56575398E-04
};
/* Precomputed: synmatrix4[k][i] = cos( (i+0.5) * (k+2.0) * pi/4.0 ) */
static const float synmatrix4[8][4] = {
{ 0.707106781186548, -0.707106781186547, -0.707106781186548, 0.707106781186547 },
{ 0.38268343236509, -0.923879532511287, 0.923879532511287, -0.38268343236509 },
{ 0, 0, 0, 0 },
{ -0.38268343236509, 0.923879532511287, -0.923879532511287, 0.382683432365091 },
{ -0.707106781186547, 0.707106781186548, 0.707106781186547, -0.707106781186547 },
{ -0.923879532511287, -0.38268343236509, 0.382683432365091, 0.923879532511288 },
{ -1, -1, -1, -1 },
{ -0.923879532511287, -0.382683432365091, 0.38268343236509, 0.923879532511287 }
};
/* Precomputed: synmatrix8[k][i] = cos( (i+0.5) * (k+4.0) * pi/8.0 ) */
static const float synmatrix8[16][8] = {
{ 0.707106781186548, -0.707106781186547, -0.707106781186548, 0.707106781186547,
0.707106781186548, -0.707106781186547, -0.707106781186547, 0.707106781186547 },
{ 0.555570233019602, -0.98078528040323, 0.195090322016128, 0.831469612302545,
-0.831469612302545, -0.195090322016128, 0.980785280403231, -0.555570233019602 },
{ 0.38268343236509, -0.923879532511287, 0.923879532511287, -0.38268343236509,
-0.382683432365091, 0.923879532511287, -0.923879532511286, 0.38268343236509 },
{ 0.195090322016128, -0.555570233019602, 0.831469612302545, -0.980785280403231,
0.98078528040323, -0.831469612302545, 0.555570233019602, -0.195090322016129 },
{ 0, 0, 0, 0,
0, 0, 0, 0 },
{ -0.195090322016128, 0.555570233019602, -0.831469612302545, 0.98078528040323,
-0.980785280403231, 0.831469612302545, -0.555570233019603, 0.19509032201613 },
{ -0.38268343236509, 0.923879532511287, -0.923879532511287, 0.382683432365091,
0.38268343236509, -0.923879532511287, 0.923879532511288, -0.382683432365091 },
{ -0.555570233019602, 0.98078528040323, -0.195090322016128, -0.831469612302545,
0.831469612302545, 0.195090322016128, -0.98078528040323, 0.555570233019606 },
{ -0.707106781186547, 0.707106781186548, 0.707106781186547, -0.707106781186547,
-0.707106781186546, 0.707106781186548, 0.707106781186546, -0.707106781186548 },
{ -0.831469612302545, 0.195090322016129, 0.980785280403231, 0.555570233019602,
-0.555570233019603, -0.98078528040323, -0.195090322016128, 0.831469612302547 },
{ -0.923879532511287, -0.38268343236509, 0.382683432365091, 0.923879532511288,
0.923879532511287, 0.382683432365089, -0.382683432365091, -0.923879532511287 },
{ -0.98078528040323, -0.831469612302545, -0.555570233019602, -0.195090322016129,
0.19509032201613, 0.555570233019606, 0.831469612302547, 0.980785280403231 },
{ -1, -1, -1, -1,
-1, -1, -1, -1 },
{ -0.98078528040323, -0.831469612302546, -0.555570233019603, -0.19509032201613,
0.195090322016128, 0.555570233019604, 0.831469612302545, 0.98078528040323 },
{ -0.923879532511287, -0.382683432365091, 0.38268343236509, 0.923879532511287,
0.923879532511288, 0.382683432365088, -0.382683432365089, -0.923879532511285 },
{ -0.831469612302545, 0.195090322016127, 0.98078528040323, 0.555570233019603,
-0.555570233019601, -0.98078528040323, -0.195090322016131, 0.831469612302545 }
};
/* Precomputed: anamatrix4[i][k] = cos( (i+0.5) * (k-2) * pi/4 ) */
static const float anamatrix4[4][8] = {
{ 0.707106781186548, 0.923879532511287, 1, 0.923879532511287,
0.707106781186548, 0.38268343236509, 0, -0.38268343236509 },
{ -0.707106781186547, 0.38268343236509, 1, 0.38268343236509,
-0.707106781186547, -0.923879532511287, 0, 0.923879532511287 },
{ -0.707106781186548, -0.38268343236509, 1, -0.38268343236509,
-0.707106781186548, 0.923879532511287, 0, -0.923879532511287 },
{ 0.707106781186547, -0.923879532511287, 1, -0.923879532511287,
0.707106781186547, -0.38268343236509, 0, 0.382683432365091 }
};
/* Precomputed: anamatrix8[i][k] = cos( (i+0.5) * (k-4) * pi/8) */
static const float anamatrix8[8][16] = {
{ 0.923879532511287, 0.98078528040323, 1, 0.98078528040323,
0.923879532511287, 0.831469612302545, 0.707106781186548, 0.555570233019602,
0.38268343236509, 0.195090322016128, 0, -0.195090322016128,
-0.38268343236509, -0.555570233019602, -0.707106781186547, -0.831469612302545 },
{ 0.38268343236509, 0.831469612302545, 1, 0.831469612302545,
0.38268343236509, -0.195090322016128, -0.707106781186547, -0.98078528040323,
-0.923879532511287, -0.555570233019602, 0, 0.555570233019602,
0.923879532511287, 0.98078528040323, 0.707106781186548, 0.195090322016129 },
{ -0.38268343236509, 0.555570233019602, 1, 0.555570233019602,
-0.38268343236509, -0.98078528040323, -0.707106781186548, 0.195090322016128,
0.923879532511287, 0.831469612302545, 0, -0.831469612302545,
-0.923879532511287, -0.195090322016128, 0.707106781186547, 0.980785280403231 },
{ -0.923879532511287, 0.195090322016128, 1, 0.195090322016128,
-0.923879532511287, -0.555570233019602, 0.707106781186547, 0.831469612302545,
-0.38268343236509, -0.980785280403231, 0, 0.98078528040323,
0.382683432365091, -0.831469612302545, -0.707106781186547, 0.555570233019602 },
{ -0.923879532511287, -0.195090322016128, 1, -0.195090322016128,
-0.923879532511287, 0.555570233019602, 0.707106781186548, -0.831469612302545,
-0.382683432365091, 0.98078528040323, 0, -0.980785280403231,
0.38268343236509, 0.831469612302545, -0.707106781186546, -0.555570233019603 },
{ -0.38268343236509, -0.555570233019602, 1, -0.555570233019602,
-0.38268343236509, 0.98078528040323, -0.707106781186547, -0.195090322016128,
0.923879532511287, -0.831469612302545, 0, 0.831469612302545,
-0.923879532511287, 0.195090322016128, 0.707106781186548, -0.98078528040323 },
{ 0.38268343236509, -0.831469612302545, 1, -0.831469612302545,
0.38268343236509, 0.195090322016129, -0.707106781186547, 0.980785280403231,
-0.923879532511286, 0.555570233019602, 0, -0.555570233019603,
0.923879532511288, -0.98078528040323, 0.707106781186546, -0.195090322016128 },
{ 0.923879532511287, -0.98078528040323, 1, -0.98078528040323,
0.923879532511287, -0.831469612302545, 0.707106781186547, -0.555570233019602,
0.38268343236509, -0.195090322016129, 0, 0.19509032201613,
-0.382683432365091, 0.555570233019606, -0.707106781186548, 0.831469612302547 }
};
#define fabs(x) ((x) < 0 ? (-x) : (x))
#define SBC_SYNCWORD 0x9C
/* sampling frequency */
#define SBC_FS_16 0x00
#define SBC_FS_32 0x01
#define SBC_FS_44 0x02
#define SBC_FS_48 0x03
/* nrof_blocks */
#define SBC_NB_4 0x00
#define SBC_NB_8 0x01
#define SBC_NB_12 0x02
#define SBC_NB_16 0x03
/* channel mode */
#define SBC_CM_MONO 0x00
#define SBC_CM_DUAL_CHANNEL 0x01
#define SBC_CM_STEREO 0x02
#define SBC_CM_JOINT_STEREO 0x03
/* allocation mode */
#define SBC_AM_LOUDNESS 0x00
#define SBC_AM_SNR 0x01
/* subbands */
#define SBC_SB_4 0x00
#define SBC_SB_8 0x01
/* This structure contains an unpacked SBC frame.
Yes, there is probably quite some unused space herein */
struct sbc_frame {
double sampling_frequency; /* in kHz */
u_int8_t blocks;
enum {
MONO = SBC_CM_MONO,
DUAL_CHANNEL = SBC_CM_DUAL_CHANNEL,
STEREO = SBC_CM_STEREO,
JOINT_STEREO = SBC_CM_JOINT_STEREO
} channel_mode;
u_int8_t channels;
enum {
LOUDNESS = SBC_AM_LOUDNESS,
SNR = SBC_AM_SNR
} allocation_method;
u_int8_t subbands;
u_int8_t bitpool;
u_int8_t join; /* bit number x set means joint stereo has been used in subband x */
u_int8_t scale_factor[2][8]; /* only the lower 4 bits of every element are to be used */
u_int16_t audio_sample[16][2][8]; /* raw integer subband samples in the frame */
double sb_sample[16][2][8]; /* modified subband samples */
double pcm_sample[2][16*8]; /* original pcm audio samples */
};
struct sbc_decoder_state {
int subbands;
float S[2][8]; /* Subband samples */
float X[2][8]; /* Audio samples */
float V[2][160], U[2][80], W[2][80]; /* Vectors */
};
struct sbc_encoder_state {
int subbands;
float S[2][8]; /* Subband samples */
float X[2][80], Y[2][16], Z[2][80]; /* Vectors */
};
/*
* Calculates the CRC-8 of the first len bits in data
*/
static const u_int8_t crc_table[256] = {
0x00, 0x1D, 0x3A, 0x27, 0x74, 0x69, 0x4E, 0x53,
0xE8, 0xF5, 0xD2, 0xCF, 0x9C, 0x81, 0xA6, 0xBB,
0xCD, 0xD0, 0xF7, 0xEA, 0xB9, 0xA4, 0x83, 0x9E,
0x25, 0x38, 0x1F, 0x02, 0x51, 0x4C, 0x6B, 0x76,
0x87, 0x9A, 0xBD, 0xA0, 0xF3, 0xEE, 0xC9, 0xD4,
0x6F, 0x72, 0x55, 0x48, 0x1B, 0x06, 0x21, 0x3C,
0x4A, 0x57, 0x70, 0x6D, 0x3E, 0x23, 0x04, 0x19,
0xA2, 0xBF, 0x98, 0x85, 0xD6, 0xCB, 0xEC, 0xF1,
0x13, 0x0E, 0x29, 0x34, 0x67, 0x7A, 0x5D, 0x40,
0xFB, 0xE6, 0xC1, 0xDC, 0x8F, 0x92, 0xB5, 0xA8,
0xDE, 0xC3, 0xE4, 0xF9, 0xAA, 0xB7, 0x90, 0x8D,
0x36, 0x2B, 0x0C, 0x11, 0x42, 0x5F, 0x78, 0x65,
0x94, 0x89, 0xAE, 0xB3, 0xE0, 0xFD, 0xDA, 0xC7,
0x7C, 0x61, 0x46, 0x5B, 0x08, 0x15, 0x32, 0x2F,
0x59, 0x44, 0x63, 0x7E, 0x2D, 0x30, 0x17, 0x0A,
0xB1, 0xAC, 0x8B, 0x96, 0xC5, 0xD8, 0xFF, 0xE2,
0x26, 0x3B, 0x1C, 0x01, 0x52, 0x4F, 0x68, 0x75,
0xCE, 0xD3, 0xF4, 0xE9, 0xBA, 0xA7, 0x80, 0x9D,
0xEB, 0xF6, 0xD1, 0xCC, 0x9F, 0x82, 0xA5, 0xB8,
0x03, 0x1E, 0x39, 0x24, 0x77, 0x6A, 0x4D, 0x50,
0xA1, 0xBC, 0x9B, 0x86, 0xD5, 0xC8, 0xEF, 0xF2,
0x49, 0x54, 0x73, 0x6E, 0x3D, 0x20, 0x07, 0x1A,
0x6C, 0x71, 0x56, 0x4B, 0x18, 0x05, 0x22, 0x3F,
0x84, 0x99, 0xBE, 0xA3, 0xF0, 0xED, 0xCA, 0xD7,
0x35, 0x28, 0x0F, 0x12, 0x41, 0x5C, 0x7B, 0x66,
0xDD, 0xC0, 0xE7, 0xFA, 0xA9, 0xB4, 0x93, 0x8E,
0xF8, 0xE5, 0xC2, 0xDF, 0x8C, 0x91, 0xB6, 0xAB,
0x10, 0x0D, 0x2A, 0x37, 0x64, 0x79, 0x5E, 0x43,
0xB2, 0xAF, 0x88, 0x95, 0xC6, 0xDB, 0xFC, 0xE1,
0x5A, 0x47, 0x60, 0x7D, 0x2E, 0x33, 0x14, 0x09,
0x7F, 0x62, 0x45, 0x58, 0x0B, 0x16, 0x31, 0x2C,
0x97, 0x8A, 0xAD, 0xB0, 0xE3, 0xFE, 0xD9, 0xC4
};
static u_int8_t sbc_crc8(const u_int8_t * data, size_t len)
{
u_int8_t crc = 0x0f;
size_t i;
u_int8_t octet;
for (i = 0; i < len / 8; i++)
crc = crc_table[crc ^ data[i]];
octet = data[i];
for (i = 0; i < len % 8; i++) {
char bit = ((octet ^ crc) & 0x80) >> 7;
crc = ((crc & 0x7f) << 1) ^ (bit ? 0x1d : 0);
octet = octet << 1;
}
return crc;
}
/*
* Code straight from the spec to calculate the bits array
* Takes a pointer to the frame in question, a pointer to the bits array and the sampling frequency (as 2 bit integer)
*/
static void sbc_calculate_bits(const struct sbc_frame *frame, int (*bits)[8], u_int8_t sf)
{
if (frame->channel_mode == MONO || frame->channel_mode == DUAL_CHANNEL) {
int bitneed[2][8], loudness, max_bitneed, bitcount, slicecount, bitslice;
int ch, sb;
for (ch = 0; ch < frame->channels; ch++) {
if (frame->allocation_method == SNR) {
for (sb = 0; sb < frame->subbands; sb++) {
bitneed[ch][sb] = frame->scale_factor[ch][sb];
}
} else {
for (sb = 0; sb < frame->subbands; sb++) {
if (frame->scale_factor[ch][sb] == 0) {
bitneed[ch][sb] = -5;
} else {
if (frame->subbands == 4) {
loudness = frame->scale_factor[ch][sb] - sbc_offset4[sf][sb];
} else {
loudness = frame->scale_factor[ch][sb] - sbc_offset8[sf][sb];
}
if (loudness > 0) {
bitneed[ch][sb] = loudness / 2;
} else {
bitneed[ch][sb] = loudness;
}
}
}
}
max_bitneed = 0;
for (sb = 0; sb < frame->subbands; sb++) {
if (bitneed[ch][sb] > max_bitneed)
max_bitneed = bitneed[ch][sb];
}
bitcount = 0;
slicecount = 0;
bitslice = max_bitneed + 1;
do {
bitslice--;
bitcount += slicecount;
slicecount = 0;
for (sb = 0; sb < frame->subbands; sb++) {
if ((bitneed[ch][sb] > bitslice + 1) && (bitneed[ch][sb] < bitslice + 16)) {
slicecount++;
} else if (bitneed[ch][sb] == bitslice + 1) {
slicecount += 2;
}
}
} while (bitcount + slicecount < frame->bitpool);
if (bitcount + slicecount == frame->bitpool) {
bitcount += slicecount;
bitslice--;
}
for (sb = 0; sb < frame->subbands; sb++) {
if (bitneed[ch][sb] < bitslice + 2) {
bits[ch][sb] = 0;
} else {
bits[ch][sb] = bitneed[ch][sb] - bitslice;
if (bits[ch][sb] > 16)
bits[ch][sb] = 16;
}
}
sb = 0;
while (bitcount < frame->bitpool && sb < frame->subbands) {
if ((bits[ch][sb] >= 2) && (bits[ch][sb] < 16)) {
bits[ch][sb]++;
bitcount++;
} else if ((bitneed[ch][sb] == bitslice + 1) && (frame->bitpool > bitcount + 1)) {
bits[ch][sb] = 2;
bitcount += 2;
}
sb++;
}
sb = 0;
while (bitcount < frame->bitpool && sb < frame->subbands) {
if (bits[ch][sb] < 16) {
bits[ch][sb]++;
bitcount++;
}
sb++;
}
}
} else if (frame->channel_mode == STEREO || frame->channel_mode == JOINT_STEREO) {
int bitneed[2][8], loudness, max_bitneed, bitcount, slicecount, bitslice;
int ch, sb;
if (frame->allocation_method == SNR) {
for (ch = 0; ch < 2; ch++) {
for (sb = 0; sb < frame->subbands; sb++) {
bitneed[ch][sb] = frame->scale_factor[ch][sb];
}
}
} else {
for (ch = 0; ch < 2; ch++) {
for (sb = 0; sb < frame->subbands; sb++) {
if (frame->scale_factor[ch][sb] == 0) {
bitneed[ch][sb] = -5;
} else {
if (frame->subbands == 4) {
loudness = frame->scale_factor[ch][sb] - sbc_offset4[sf][sb];
} else {
loudness = frame->scale_factor[ch][sb] - sbc_offset8[sf][sb];
}
if (loudness > 0) {
bitneed[ch][sb] = loudness / 2;
} else {
bitneed[ch][sb] = loudness;
}
}
}
}
}
max_bitneed = 0;
for (ch = 0; ch < 2; ch++) {
for (sb = 0; sb < frame->subbands; sb++) {
if (bitneed[ch][sb] > max_bitneed)
max_bitneed = bitneed[ch][sb];
}
}
bitcount = 0;
slicecount = 0;
bitslice = max_bitneed + 1;
do {
bitslice--;
bitcount += slicecount;
slicecount = 0;
for (ch = 0; ch < 2; ch++) {
for (sb = 0; sb < frame->subbands; sb++) {
if ((bitneed[ch][sb] > bitslice + 1) && (bitneed[ch][sb] < bitslice + 16)) {
slicecount++;
} else if (bitneed[ch][sb] == bitslice + 1) {
slicecount += 2;
}
}
}
} while (bitcount + slicecount < frame->bitpool);
if (bitcount + slicecount == frame->bitpool) {
bitcount += slicecount;
bitslice--;
}
for (ch = 0; ch < 2; ch++) {
for (sb = 0; sb < frame->subbands; sb++) {
if (bitneed[ch][sb] < bitslice + 2) {
bits[ch][sb] = 0;
} else {
bits[ch][sb] = bitneed[ch][sb] - bitslice;
if (bits[ch][sb] > 16)
bits[ch][sb] = 16;
}
}
}
ch = 0;
sb = 0;
while ((bitcount < frame->bitpool) && (sb < frame->subbands)) {
if ((bits[ch][sb] >= 2) && (bits[ch][sb] < 16)) {
bits[ch][sb]++;
bitcount++;
} else if ((bitneed[ch][sb] == bitslice + 1) && (frame->bitpool > bitcount + 1)) {
bits[ch][sb] = 2;
bitcount += 2;
}
if (ch == 1) {
ch = 0;
sb++;
} else {
ch = 1;
}
}
ch = 0;
sb = 0;
while ((bitcount < frame->bitpool) && (sb < frame->subbands)) {
if (bits[ch][sb] < 16) {
bits[ch][sb]++;
bitcount++;
}
if (ch == 1) {
ch = 0;
sb++;
} else {
ch = 1;
}
}
}
}
/*
* Unpacks a SBC frame at the beginning of the stream in data,
* which has at most len bytes into frame.
* Returns the length in bytes of the packed frame, or a negative
* value on error. The error codes are:
*
* -1 Data stream too short
* -2 Sync byte incorrect
* -3 CRC8 incorrect
* -4 Bitpool value out of bounds
*/
static int sbc_unpack_frame(const u_int8_t * data, struct sbc_frame *frame, size_t len)
{
int consumed;
/* Will copy the parts of the header that are relevant to crc calculation here */
u_int8_t crc_header[11] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
int crc_pos = 0;
u_int8_t sf; /* sampling_frequency, temporarily needed as array index */
int ch, sb, blk, bit; /* channel, subband, block and bit standard counters */
int bits[2][8]; /* bits distribution */
int levels[2][8]; /* levels derived from that */
double scalefactor[2][8]; /* derived from frame->scale_factors */
if (len < 4) {
return -1;
}
if (data[0] != SBC_SYNCWORD) {
return -2;
}
sf = (data[1] >> 6) & 0x03;
switch (sf) {
case SBC_FS_16:
frame->sampling_frequency = 16;
break;
case SBC_FS_32:
frame->sampling_frequency = 32;
break;
case SBC_FS_44:
frame->sampling_frequency = 44.1;
break;
case SBC_FS_48:
frame->sampling_frequency = 48;
break;
}
switch ((data[1] >> 4) & 0x03) {
case SBC_NB_4:
frame->blocks = 4;
break;
case SBC_NB_8:
frame->blocks = 8;
break;
case SBC_NB_12:
frame->blocks = 12;
break;
case SBC_NB_16:
frame->blocks = 16;
break;
}
frame->channel_mode = (data[1] >> 2) & 0x03;
switch (frame->channel_mode) {
case MONO:
frame->channels = 1;
break;
case DUAL_CHANNEL: /* fall-through */
case STEREO:
case JOINT_STEREO:
frame->channels = 2;
break;
}
frame->allocation_method = (data[1] >> 1) & 0x01;
frame->subbands = (data[1] & 0x01) ? 8 : 4;
frame->bitpool = data[2];
if (((frame->channel_mode == MONO || frame->channel_mode == DUAL_CHANNEL)
&& frame->bitpool > 16 * frame->subbands)
|| ((frame->channel_mode == STEREO || frame->channel_mode == JOINT_STEREO)
&& frame->bitpool > 32 * frame->subbands)) {
return -4;
}
/* data[3] is crc, we're checking it later */
consumed = 32;
crc_header[0] = data[1];
crc_header[1] = data[2];
crc_pos = 16;
if (frame->channel_mode == JOINT_STEREO) {
if (len * 8 < consumed + frame->subbands) {
return -1;
} else {
frame->join = 0x00;
for (sb = 0; sb < frame->subbands - 1; sb++) {
frame->join |= ((data[4] >> (7 - sb)) & 0x01) << sb;
}
if (frame->subbands == 4) {
crc_header[crc_pos / 8] = data[4] & 0xf0;
} else {
crc_header[crc_pos / 8] = data[4];
}
consumed += frame->subbands;
crc_pos += frame->subbands;
}
}
if (len * 8 < consumed + (4 * frame->subbands * frame->channels)) {
return -1;
} else {
for (ch = 0; ch < frame->channels; ch++) {
for (sb = 0; sb < frame->subbands; sb++) {
/* FIXME assert(consumed % 4 == 0); */
frame->scale_factor[ch][sb] = (data[consumed / 8] >> (4 - (consumed % 8))) & 0x0F;
crc_header[crc_pos / 8] |= frame->scale_factor[ch][sb] << (4 - (crc_pos % 8));
consumed += 4;
crc_pos += 4;
}
}
}
if (data[3] != sbc_crc8(crc_header, crc_pos)) {
return -3;
}
sbc_calculate_bits(frame, bits, sf);
for (blk = 0; blk < frame->blocks; blk++) {
for (ch = 0; ch < frame->channels; ch++) {
for (sb = 0; sb < frame->subbands; sb++) {
frame->audio_sample[blk][ch][sb] = 0;
if (bits[ch][sb] != 0) {
for (bit = 0; bit < bits[ch][sb]; bit++) {
int b; /* A bit */
if (consumed > len * 8) {
return -1;
}
b = (data[consumed / 8] >> (7 - (consumed % 8))) & 0x01;
frame->audio_sample[blk][ch][sb] |= b << (bits[ch][sb] - bit - 1);
consumed++;
}
}
}
}
}
for (ch = 0; ch < frame->channels; ch++) {
for (sb = 0; sb < frame->subbands; sb++) {
levels[ch][sb] = (1 << bits[ch][sb]) - 1;
scalefactor[ch][sb] = 2 << frame->scale_factor[ch][sb];
}
}
for (blk = 0; blk < frame->blocks; blk++) {
for (ch = 0; ch < frame->channels; ch++) {
for (sb = 0; sb < frame->subbands; sb++) {
if (levels[ch][sb] > 0) {
frame->sb_sample[blk][ch][sb] =
scalefactor[ch][sb] * ((frame->audio_sample[blk][ch][sb] * 2.0 + 1.0) /
levels[ch][sb] - 1.0);
} else {
frame->sb_sample[blk][ch][sb] = 0;
}
}
}
}
if (frame->channel_mode == JOINT_STEREO) {
for (blk = 0; blk < frame->blocks; blk++) {
for (sb = 0; sb < frame->subbands; sb++) {
if (frame->join & (0x01 << sb)) {
frame->sb_sample[blk][0][sb] =
frame->sb_sample[blk][0][sb] + frame->sb_sample[blk][1][sb];
frame->sb_sample[blk][1][sb] =
frame->sb_sample[blk][0][sb] - 2 * frame->sb_sample[blk][1][sb];
}
}
}
}
if (consumed % 8 != 0)
consumed += 8 - (consumed % 8);
return consumed / 8;
}
static void sbc_decoder_init(struct sbc_decoder_state *state, const struct sbc_frame *frame)
{
memset(&state->S, 0, sizeof(state->S));
memset(&state->X, 0, sizeof(state->X));
memset(&state->V, 0, sizeof(state->V));
memset(&state->U, 0, sizeof(state->U));
memset(&state->W, 0, sizeof(state->W));
state->subbands = frame->subbands;
}
static inline void sbc_synthesize_four(struct sbc_decoder_state *state,
struct sbc_frame *frame, int ch, int blk)
{
int i, j, k;
/* Input 4 New Subband Samples */
for (i = 0; i < 4; i++)
state->S[ch][i] = frame->sb_sample[blk][ch][i];
/* Shifting */
for (i = 79; i >= 8; i--)
state->V[ch][i] = state->V[ch][i - 8];
/* Matrixing */
for (k = 0; k < 8; k++) {
state->V[ch][k] = 0;
for (i = 0; i < 4; i++)
state->V[ch][k] += synmatrix4[k][i] * state->S[ch][i];
}
/* Build a 40 values vector U */
for (i = 0; i <= 4; i++) {
for (j = 0; j < 4; j++) {
state->U[ch][i * 8 + j] = state->V[ch][i * 16 + j];
state->U[ch][i * 8 + j + 4] = state->V[ch][i * 16 + j + 12];
}
}
/* Window by 40 coefficients */
for (i = 0; i < 40; i++)
state->W[ch][i] = state->U[ch][i] * sbc_proto_4_40[i] * (-4);
/* Calculate 4 audio samples */
for (j = 0; j < 4; j++) {
state->X[ch][j] = 0;
for (i = 0; i < 10; i++)
state->X[ch][j] += state->W[ch][j + 4 * i];
}
/* Output 4 reconstructed Audio Samples */
for (i = 0; i < 4; i++)
frame->pcm_sample[ch][blk * 4 + i] = state->X[ch][i];
}
static inline void sbc_synthesize_eight(struct sbc_decoder_state *state,
struct sbc_frame *frame, int ch, int blk)
{
int i, j, k;
/* Input 8 New Subband Samples */
for (i = 0; i < 8; i++)
state->S[ch][i] = frame->sb_sample[blk][ch][i];
/* Shifting */
for (i = 159; i >= 16; i--)
state->V[ch][i] = state->V[ch][i - 16];
/* Matrixing */
for (k = 0; k < 16; k++) {
state->V[ch][k] = 0;
for (i = 0; i < 8; i++) {
state->V[ch][k] += synmatrix8[k][i] * state->S[ch][i];
}
}
/* Build a 80 values vector U */
for (i = 0; i <= 4; i++) {
for (j = 0; j < 8; j++) {
state->U[ch][i * 16 + j] = state->V[ch][i * 32 + j];
state->U[ch][i * 16 + j + 8] = state->V[ch][i * 32 + j + 24];
}
}
/* Window by 80 coefficients */
for (i = 0; i < 80; i++)
state->W[ch][i] = state->U[ch][i] * sbc_proto_8_80[i] * (-4);
/* Calculate 8 audio samples */
for (j = 0; j < 8; j++) {
state->X[ch][j] = 0;
for (i = 0; i < 10; i++)
state->X[ch][j] += state->W[ch][j + 8 * i];
}
/* Ouput 8 reconstructed Audio Samples */
for (i = 0; i < 8; i++)
frame->pcm_sample[ch][blk * 8 + i] = state->X[ch][i];
}
static int sbc_synthesize_audio(struct sbc_decoder_state *state, struct sbc_frame *frame)
{
int ch, blk;
switch (frame->subbands) {
case 4:
for (ch = 0; ch < frame->channels; ch++) {
memset(frame->pcm_sample[ch], 0,
sizeof(frame->pcm_sample[ch]));
for (blk = 0; blk < frame->blocks; blk++)
sbc_synthesize_four(state, frame, ch, blk);
}
return frame->blocks * 4;
case 8:
for (ch = 0; ch < frame->channels; ch++) {
memset(frame->pcm_sample[ch], 0,
sizeof(frame->pcm_sample[ch]));
for (blk = 0; blk < frame->blocks; blk++)
sbc_synthesize_eight(state, frame, ch, blk);
}
return frame->blocks * 8;
default:
return -EIO;
}
}
static void sbc_encoder_init(struct sbc_encoder_state *state, const struct sbc_frame *frame)
{
memset(&state->S, 0, sizeof(state->S));
memset(&state->X, 0, sizeof(state->X));
memset(&state->Y, 0, sizeof(state->Y));
memset(&state->Z, 0, sizeof(state->Z));
state->subbands = frame->subbands;
}
static inline void sbc_analyze_four(struct sbc_encoder_state *state,
struct sbc_frame *frame, int ch, int blk)
{
int i, k;
/* Input 4 New Audio Samples */
for (i = 39; i >= 4; i--)
state->X[ch][i] = state->X[ch][i - 4];
for (i = 3; i >= 0; i--)
state->X[ch][i] = frame->pcm_sample[ch][blk * 4 + (3 - i)];
/* Windowing by 40 coefficients */
for (i = 0; i < 40; i++)
state->Z[ch][i] = sbc_proto_4_40[i] * state->X[ch][i];
/* Partial calculation */
for (i = 0; i < 8; i++) {
state->Y[ch][i] = 0;
for (k = 0; k < 5; k++)
state->Y[ch][i] += state->Z[ch][i + k * 8];
}
/* Calculate 4 subband samples by Matrixing */
for (i = 0; i < 4; i++) {
state->S[ch][i] = 0;
for (k = 0; k < 8; k++)
state->S[ch][i] += anamatrix4[i][k] * state->Y[ch][k];
}
/* Output 4 Subband Samples */
for (i = 0; i < 4; i++)
frame->sb_sample[blk][ch][i] = state->S[ch][i];
}
static inline void sbc_analyze_eight(struct sbc_encoder_state *state,
struct sbc_frame *frame, int ch, int blk)
{
int i, k;
/* Input 8 Audio Samples */
for (i = 79; i >= 8; i--)
state->X[ch][i] = state->X[ch][i - 8];
for (i = 7; i >= 0; i--)
state->X[ch][i] = frame->pcm_sample[ch][blk * 8 + (7 - i)];
/* Windowing by 80 coefficients */
for (i = 0; i < 80; i++)
state->Z[ch][i] = sbc_proto_8_80[i] * state->X[ch][i];
/* Partial calculation */
for (i = 0; i < 16; i++) {
state->Y[ch][i] = 0;
for (k = 0; k < 5; k++)
state->Y[ch][i] += state->Z[ch][i + k * 16];
}
/* Calculate 8 subband samples by Matrixing */
for (i = 0; i < 8; i++) {
state->S[ch][i] = 0;
for (k = 0; k < 16; k++)
state->S[ch][i] += anamatrix8[i][k] * state->Y[ch][k];
}
/* Output 8 Subband Samples */
for (i = 0; i < 8; i++)
frame->sb_sample[blk][ch][i] = state->S[ch][i];
}
static int sbc_analyze_audio(struct sbc_encoder_state *state, struct sbc_frame *frame)
{
int ch, blk;
switch (frame->subbands) {
case 4:
for (ch = 0; ch < frame->channels; ch++)
for (blk = 0; blk < frame->blocks; blk++) {
memset(frame->sb_sample[blk][ch], 0,
sizeof(frame->sb_sample[blk][ch]));
sbc_analyze_four(state, frame, ch, blk);
}
return frame->blocks * 4;
case 8:
for (ch = 0; ch < frame->channels; ch++)
for (blk = 0; blk < frame->blocks; blk++) {
memset(frame->sb_sample[blk][ch], 0,
sizeof(frame->sb_sample[blk][ch]));
sbc_analyze_eight(state, frame, ch, blk);
}
return frame->blocks * 8;
default:
return -EIO;
}
}
/*
* Packs the SBC frame from frame into the memory at data. At most len
* bytes will be used, should more memory be needed an appropriate
* error code will be returned. Returns the length of the packed frame
* on success or a negative value on error.
*
* The error codes are:
* -1 Not enough memory reserved
* -2 Unsupported sampling rate
* -3 Unsupported number of blocks
* -4 Unsupported number of subbands
* -5 Bitpool value out of bounds
* -99 not implemented
*/
static int sbc_pack_frame(u_int8_t * data, struct sbc_frame *frame, size_t len)
{
int produced;
/* Will copy the header parts for CRC-8 calculation here */
u_int8_t crc_header[11] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
int crc_pos = 0;
u_int8_t sf; /* Sampling frequency as temporary value for table lookup */
int ch, sb, blk, bit; /* channel, subband, block and bit counters */
int bits[2][8]; /* bits distribution */
int levels[2][8]; /* levels are derived from that */
double scalefactor[2][8]; /* derived from frame->scale_factor */
if (len < 4) {
return -1;
}
/* Clear first 4 bytes of data (that's the constant length part of the SBC header) */
memset(data, 0, 4);
data[0] = SBC_SYNCWORD;
if (frame->sampling_frequency == 16) {
data[1] |= (SBC_FS_16 & 0x03) << 6;
sf = SBC_FS_16;
} else if (frame->sampling_frequency == 32) {
data[1] |= (SBC_FS_32 & 0x03) << 6;
sf = SBC_FS_32;
} else if (frame->sampling_frequency == 44.1) {
data[1] |= (SBC_FS_44 & 0x03) << 6;
sf = SBC_FS_44;
} else if (frame->sampling_frequency == 48) {
data[1] |= (SBC_FS_48 & 0x03) << 6;
sf = SBC_FS_48;
} else {
return -2;
}
switch (frame->blocks) {
case 4:
data[1] |= (SBC_NB_4 & 0x03) << 4;
break;
case 8:
data[1] |= (SBC_NB_8 & 0x03) << 4;
break;
case 12:
data[1] |= (SBC_NB_12 & 0x03) << 4;
break;
case 16:
data[1] |= (SBC_NB_16 & 0x03) << 4;
break;
default:
return -3;
break;
}
data[1] |= (frame->channel_mode & 0x03) << 2;
data[1] |= (frame->allocation_method & 0x01) << 1;
switch (frame->subbands) {
case 4:
/* Nothing to do */
break;
case 8:
data[1] |= 0x01;
break;
default:
return -4;
break;
}
data[2] = frame->bitpool;
if (((frame->channel_mode == MONO || frame->channel_mode == DUAL_CHANNEL)
&& frame->bitpool > 16 * frame->subbands)
|| ((frame->channel_mode == STEREO || frame->channel_mode == JOINT_STEREO)
&& frame->bitpool > 32 * frame->subbands)) {
return -5;
}
/* Can't fill in crc yet */
produced = 32;
crc_header[0] = data[1];
crc_header[1] = data[2];
crc_pos = 16;
for (ch = 0; ch < frame->channels; ch++) {
for (sb = 0; sb < frame->subbands; sb++) {
frame->scale_factor[ch][sb] = 0;
scalefactor[ch][sb] = 2;
for (blk = 0; blk < frame->blocks; blk++) {
while (scalefactor[ch][sb] < fabs(frame->sb_sample[blk][ch][sb])) {
frame->scale_factor[ch][sb]++;
scalefactor[ch][sb] *= 2;
}
}
}
}
if (frame->channel_mode == JOINT_STEREO) {
float sb_sample_j[16][2][7]; /* like frame->sb_sample but joint stereo */
int scalefactor_j[2][7], scale_factor_j[2][7]; /* scalefactor and scale_factor in joint case */
/* Calculate joint stereo signal */
for (sb = 0; sb < frame->subbands - 1; sb++) {
for (blk = 0; blk < frame->blocks; blk++) {
sb_sample_j[blk][0][sb] = (frame->sb_sample[blk][0][sb]
+ frame->sb_sample[blk][1][sb]) / 2;
sb_sample_j[blk][1][sb] = (frame->sb_sample[blk][0][sb]
- frame->sb_sample[blk][1][sb]) / 2;
}
}
/* calculate scale_factor_j and scalefactor_j for joint case */
for (ch = 0; ch < 2; ch++) {
for (sb = 0; sb < frame->subbands - 1; sb++) {
scale_factor_j[ch][sb] = 0;
scalefactor_j[ch][sb] = 2;
for (blk = 0; blk < frame->blocks; blk++) {
while (scalefactor_j[ch][sb] < fabs(sb_sample_j[blk][ch][sb])) {
scale_factor_j[ch][sb]++;
scalefactor_j[ch][sb] *= 2;
}
}
}
}
/* decide which subbands to join */
frame->join = 0;
for (sb = 0; sb < frame->subbands - 1; sb++) {
if ( (scalefactor[0][sb] + scalefactor[1][sb]) >
(scalefactor_j[0][sb] + scalefactor_j[1][sb]) ) {
/* use joint stereo for this subband */
frame->join |= 1 << sb;
frame->scale_factor[0][sb] = scale_factor_j[0][sb];
frame->scale_factor[1][sb] = scale_factor_j[1][sb];
scalefactor[0][sb] = scalefactor_j[0][sb];
scalefactor[1][sb] = scalefactor_j[1][sb];
for (blk = 0; blk < frame->blocks; blk++) {
frame->sb_sample[blk][0][sb] = sb_sample_j[blk][0][sb];
frame->sb_sample[blk][1][sb] = sb_sample_j[blk][1][sb];
}
}
}
if (len * 8 < produced + frame->subbands) {
return -1;
} else {
data[4] = 0;
for (sb = 0; sb < frame->subbands - 1; sb++) {
data[4] |= ((frame->join >> sb) & 0x01) << (7 - sb);
}
if (frame->subbands == 4) {
crc_header[crc_pos / 8] = data[4] & 0xf0;
} else {
crc_header[crc_pos / 8] = data[4];
}
produced += frame->subbands;
crc_pos += frame->subbands;
}
}
if (len * 8 < produced + (4 * frame->subbands * frame->channels)) {
return -1;
} else {
for (ch = 0; ch < frame->channels; ch++) {
for (sb = 0; sb < frame->subbands; sb++) {
if (produced % 8 == 0)
data[produced / 8] = 0;
data[produced / 8] |= ((frame->scale_factor[ch][sb] & 0x0F) << (4 - (produced % 8)));
crc_header[crc_pos / 8] |=
((frame->scale_factor[ch][sb] & 0x0F) << (4 - (crc_pos % 8)));
produced += 4;
crc_pos += 4;
}
}
}
data[3] = sbc_crc8(crc_header, crc_pos);
sbc_calculate_bits(frame, bits, sf);
for (ch = 0; ch < frame->channels; ch++) {
for (sb = 0; sb < frame->subbands; sb++) {
levels[ch][sb] = (1 << bits[ch][sb]) - 1;
}
}
for (blk = 0; blk < frame->blocks; blk++) {
for (ch = 0; ch < frame->channels; ch++) {
for (sb = 0; sb < frame->subbands; sb++) {
if (levels[ch][sb] > 0) {
frame->audio_sample[blk][ch][sb] =
(u_int16_t) (((frame->sb_sample[blk][ch][sb] / scalefactor[ch][sb] +
1.0) * levels[ch][sb]) / 2.0);
} else {
frame->audio_sample[blk][ch][sb] = 0;
}
}
}
}
for (blk = 0; blk < frame->blocks; blk++) {
for (ch = 0; ch < frame->channels; ch++) {
for (sb = 0; sb < frame->subbands; sb++) {
if (bits[ch][sb] != 0) {
for (bit = 0; bit < bits[ch][sb]; bit++) {
int b; /* A bit */
if (produced > len * 8) {
return -1;
}
if (produced % 8 == 0) {
data[produced / 8] = 0;
}
b = ((frame->audio_sample[blk][ch][sb]) >> (bits[ch][sb] - bit -
1)) & 0x01;
data[produced / 8] |= b << (7 - (produced % 8));
produced++;
}
}
}
}
}
if (produced % 8 != 0) {
produced += 8 - (produced % 8);
}
return produced / 8;
}
struct sbc_priv {
int init;
struct sbc_frame frame;
struct sbc_decoder_state dec_state;
struct sbc_encoder_state enc_state;
};
int sbc_init(sbc_t *sbc, unsigned long flags)
{
if (!sbc)
return -EIO;
memset(sbc, 0, sizeof(sbc_t));
sbc->priv = malloc(sizeof(struct sbc_priv));
if (!sbc->priv)
return -ENOMEM;
memset(sbc->priv, 0, sizeof(struct sbc_priv));
sbc->rate = 44100;
sbc->channels = 2;
sbc->subbands = 8;
sbc->blocks = 16;
sbc->bitpool = 32;
return 0;
}
int sbc_decode(sbc_t *sbc, void *data, int count)
{
struct sbc_priv *priv;
char *ptr;
int i, ch, framelen, samples;
if (!sbc)
return -EIO;
priv = sbc->priv;
framelen = sbc_unpack_frame(data, &priv->frame, count);
if (!priv->init) {
sbc_decoder_init(&priv->dec_state, &priv->frame);
priv->init = 1;
sbc->rate = priv->frame.sampling_frequency * 1000;
sbc->channels = priv->frame.channels;
sbc->subbands = priv->frame.subbands;
sbc->blocks = priv->frame.blocks;
sbc->bitpool = priv->frame.bitpool;
}
samples = sbc_synthesize_audio(&priv->dec_state, &priv->frame);
if (!sbc->data) {
sbc->size = samples * priv->frame.channels * 2;
sbc->data = malloc(sbc->size);
}
if (sbc->size < samples * priv->frame.channels * 2) {
sbc->size = samples * priv->frame.channels * 2;
sbc->data = realloc(sbc->data, sbc->size);
}
if (!sbc->data) {
sbc->size = 0;
return -ENOMEM;
}
ptr = sbc->data;
for (i = 0; i < samples; i++) {
for (ch = 0; ch < priv->frame.channels; ch++) {
int16_t s = (int16_t)(priv->frame.pcm_sample[ch][i]);
*ptr++ = (s & 0xff00) >> 8;
*ptr++ = (s & 0x00ff);
}
}
sbc->len = samples * priv->frame.channels * 2;
sbc->duration = (1000000 * priv->frame.subbands * priv->frame.blocks) / sbc->rate;
return framelen;
}
int sbc_encode(sbc_t *sbc, void *data, int count)
{
struct sbc_priv *priv;
char *ptr;
int i, ch, framelen, samples;
if (!sbc)
return -EIO;
priv = sbc->priv;
if (!priv->init) {
priv->frame.sampling_frequency = ((double) sbc->rate) / 1000;
priv->frame.channels = sbc->channels;
if (sbc->channels > 1)
priv->frame.channel_mode = STEREO;
else
priv->frame.channel_mode = MONO;
priv->frame.allocation_method = SNR;
priv->frame.subbands = sbc->subbands;
priv->frame.blocks = sbc->blocks;
priv->frame.bitpool = sbc->bitpool;
sbc_encoder_init(&priv->enc_state, &priv->frame);
priv->init = 1;
}
ptr = data;
for (i = 0; i < priv->frame.subbands * priv->frame.blocks; i++) {
for (ch = 0; ch < sbc->channels; ch++) {
//int16_t s = (ptr[0] & 0xff) << 8 | (ptr[1] & 0xff);
int16_t s = (ptr[1] & 0xff) << 8 | (ptr[2] & 0xff);
ptr += 2;
priv->frame.pcm_sample[ch][i] = ((double) s);
}
}
samples = sbc_analyze_audio(&priv->enc_state, &priv->frame);
if (!sbc->data) {
sbc->size = 1024;
sbc->data = malloc(sbc->size);
}
if (!sbc->data) {
sbc->size = 0;
return -ENOMEM;
}
framelen = sbc_pack_frame(sbc->data, &priv->frame, sbc->size);
sbc->len = framelen;
sbc->duration = (1000000 * priv->frame.subbands * priv->frame.blocks) / sbc->rate;
return samples * sbc->channels * 2;
}
void sbc_finish(sbc_t *sbc)
{
if (!sbc)
return;
if (sbc->data)
free(sbc->data);
if (sbc->priv)
free(sbc->priv);
memset(sbc, 0, sizeof(sbc_t));
}
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