mirror of https://git.ffmpeg.org/ffmpeg.git
272 lines
8.8 KiB
C
272 lines
8.8 KiB
C
/*
|
|
* Bluetooth low-complexity, subband codec (SBC)
|
|
*
|
|
* Copyright (C) 2017 Aurelien Jacobs <aurel@gnuage.org>
|
|
* Copyright (C) 2012-2013 Intel Corporation
|
|
* Copyright (C) 2008-2010 Nokia Corporation
|
|
* Copyright (C) 2004-2010 Marcel Holtmann <marcel@holtmann.org>
|
|
* Copyright (C) 2004-2005 Henryk Ploetz <henryk@ploetzli.ch>
|
|
* Copyright (C) 2005-2008 Brad Midgley <bmidgley@xmission.com>
|
|
*
|
|
* This file is part of FFmpeg.
|
|
*
|
|
* FFmpeg 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.
|
|
*
|
|
* FFmpeg 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 FFmpeg; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
/**
|
|
* @file
|
|
* SBC common functions for the encoder and decoder
|
|
*/
|
|
|
|
#include "avcodec.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 }
|
|
};
|
|
|
|
/*
|
|
* Calculates the CRC-8 of the first len bits in data
|
|
*/
|
|
uint8_t sbc_crc8(const AVCRC *ctx, const uint8_t *data, size_t len)
|
|
{
|
|
size_t byte_length = len >> 3;
|
|
int bit_length = len & 7;
|
|
uint8_t crc;
|
|
|
|
crc = av_crc(ctx, 0x0F, data, byte_length);
|
|
|
|
if (bit_length) {
|
|
uint8_t bits = data[byte_length];
|
|
while (bit_length--) {
|
|
int8_t mask = bits ^ crc;
|
|
crc = (crc << 1) ^ ((mask >> 7) & 0x1D);
|
|
bits <<= 1;
|
|
}
|
|
}
|
|
|
|
return crc;
|
|
}
|
|
|
|
/*
|
|
* Code straight from the spec to calculate the bits array
|
|
* Takes a pointer to the frame in question and a pointer to the bits array
|
|
*/
|
|
void ff_sbc_calculate_bits(const struct sbc_frame *frame, int (*bits)[8])
|
|
{
|
|
int subbands = frame->subbands;
|
|
uint8_t sf = frame->frequency;
|
|
|
|
if (frame->mode == MONO || frame->mode == DUAL_CHANNEL) {
|
|
int bitneed[2][8], loudness, max_bitneed, bitcount, slicecount, bitslice;
|
|
int ch, sb;
|
|
|
|
for (ch = 0; ch < frame->channels; ch++) {
|
|
max_bitneed = 0;
|
|
if (frame->allocation == SNR) {
|
|
for (sb = 0; sb < subbands; sb++) {
|
|
bitneed[ch][sb] = frame->scale_factor[ch][sb];
|
|
if (bitneed[ch][sb] > max_bitneed)
|
|
max_bitneed = bitneed[ch][sb];
|
|
}
|
|
} else {
|
|
for (sb = 0; sb < subbands; sb++) {
|
|
if (frame->scale_factor[ch][sb] == 0)
|
|
bitneed[ch][sb] = -5;
|
|
else {
|
|
if (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;
|
|
}
|
|
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 < 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 < 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;
|
|
}
|
|
}
|
|
|
|
for (sb = 0; bitcount < frame->bitpool &&
|
|
sb < subbands; sb++) {
|
|
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;
|
|
}
|
|
}
|
|
|
|
for (sb = 0; bitcount < frame->bitpool &&
|
|
sb < subbands; sb++) {
|
|
if (bits[ch][sb] < 16) {
|
|
bits[ch][sb]++;
|
|
bitcount++;
|
|
}
|
|
}
|
|
|
|
}
|
|
|
|
} else if (frame->mode == STEREO || frame->mode == JOINT_STEREO) {
|
|
int bitneed[2][8], loudness, max_bitneed, bitcount, slicecount, bitslice;
|
|
int ch, sb;
|
|
|
|
max_bitneed = 0;
|
|
if (frame->allocation == SNR) {
|
|
for (ch = 0; ch < 2; ch++) {
|
|
for (sb = 0; sb < subbands; sb++) {
|
|
bitneed[ch][sb] = frame->scale_factor[ch][sb];
|
|
if (bitneed[ch][sb] > max_bitneed)
|
|
max_bitneed = bitneed[ch][sb];
|
|
}
|
|
}
|
|
} else {
|
|
for (ch = 0; ch < 2; ch++) {
|
|
for (sb = 0; sb < subbands; sb++) {
|
|
if (frame->scale_factor[ch][sb] == 0)
|
|
bitneed[ch][sb] = -5;
|
|
else {
|
|
if (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;
|
|
}
|
|
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 < 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 < 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) {
|
|
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++;
|
|
if (sb >= subbands)
|
|
break;
|
|
} else
|
|
ch = 1;
|
|
}
|
|
|
|
ch = 0;
|
|
sb = 0;
|
|
while (bitcount < frame->bitpool) {
|
|
if (bits[ch][sb] < 16) {
|
|
bits[ch][sb]++;
|
|
bitcount++;
|
|
}
|
|
if (ch == 1) {
|
|
ch = 0;
|
|
sb++;
|
|
if (sb >= subbands)
|
|
break;
|
|
} else
|
|
ch = 1;
|
|
}
|
|
|
|
}
|
|
|
|
}
|