virtualenv/FFmpeg
1
0
Fork 0
mirror of https://github.com/FFmpeg/FFmpeg.git synced 2024-12-23 12:43:46 +02:00
Code Issues Releases Activity

aptx: implement the aptX bluetooth codec

Browse Source 
The encoder was reverse engineered from binary library and from
EP0398973B1 patent (long expired).
The decoder was simply deduced from the encoder.
This commit is contained in:
Aurelien Jacobs 2017-11-10 22:09:23 +01:00 committed by Rostislav Pehlivanov
parent 81c021c6a2
commit a337b36b8b
6 changed files with 873 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
doc/general.texi
View File

@ -993,6 +993,8 @@ following image formats are supported:
@item Amazing Studio PAF Audio @tab @tab X
@item Apple lossless audio @tab X @tab X
@tab QuickTime fourcc 'alac'
@item aptX @tab X @tab X
@tab Used in Bluetooth A2DP
@item ATRAC1 @tab @tab X
@item ATRAC3 @tab @tab X
@item ATRAC3+ @tab @tab X

2
libavcodec/Makefile
View File

@ -188,6 +188,8 @@ OBJS-$(CONFIG_AMV_ENCODER) += mjpegenc.o mjpegenc_common.o \
OBJS-$(CONFIG_ANM_DECODER) += anm.o
OBJS-$(CONFIG_ANSI_DECODER) += ansi.o cga_data.o
OBJS-$(CONFIG_APE_DECODER) += apedec.o
OBJS-$(CONFIG_APTX_DECODER) += aptx.o
OBJS-$(CONFIG_APTX_ENCODER) += aptx.o
OBJS-$(CONFIG_APNG_DECODER) += png.o pngdec.o pngdsp.o
OBJS-$(CONFIG_APNG_ENCODER) += png.o pngenc.o
OBJS-$(CONFIG_SSA_DECODER) += assdec.o ass.o

1
libavcodec/allcodecs.c
View File

@ -406,6 +406,7 @@ static void register_all(void)
REGISTER_DECODER(AMRNB, amrnb);
REGISTER_DECODER(AMRWB, amrwb);
REGISTER_DECODER(APE, ape);
REGISTER_ENCDEC (APTX, aptx);
REGISTER_DECODER(ATRAC1, atrac1);
REGISTER_DECODER(ATRAC3, atrac3);
REGISTER_DECODER(ATRAC3AL, atrac3al);

860
libavcodec/aptx.c Normal file
View File

@ -0,0 +1,860 @@
/*
* Audio Processing Technology codec for Bluetooth (aptX)
*
* Copyright (C) 2017 Aurelien Jacobs <aurel@gnuage.org>
*
* 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
*/
#include "libavutil/intreadwrite.h"
#include "avcodec.h"
#include "internal.h"
#include "mathops.h"
#include "audio_frame_queue.h"
enum channels {
LEFT,
RIGHT,
NB_CHANNELS
};
enum subbands {
LF, // Low Frequency (0-5.5 kHz)
MLF, // Medium-Low Frequency (5.5-11kHz)
MHF, // Medium-High Frequency (11-16.5kHz)
HF, // High Frequency (16.5-22kHz)
NB_SUBBANDS
};
#define NB_FILTERS 2
#define FILTER_TAPS 16
typedef struct {
int pos;
int32_t buffer[2*FILTER_TAPS];
} FilterSignal;
typedef struct {
FilterSignal outer_filter_signal[NB_FILTERS];
FilterSignal inner_filter_signal[NB_FILTERS][NB_FILTERS];
} QMFAnalysis;
typedef struct {
int32_t quantized_sample;
int32_t quantized_sample_parity_change;
int32_t error;
} Quantize;
typedef struct {
int32_t quantization_factor;
int32_t factor_select;
int32_t reconstructed_difference;
} InvertQuantize;
typedef struct {
int32_t prev_sign[2];
int32_t s_weight[2];
int32_t d_weight[24];
int32_t pos;
int32_t reconstructed_differences[48];
int32_t previous_reconstructed_sample;
int32_t predicted_difference;
int32_t predicted_sample;
} Prediction;
typedef struct {
int32_t codeword_history;
int32_t dither_parity;
int32_t dither[NB_SUBBANDS];
QMFAnalysis qmf;
Quantize quantize[NB_SUBBANDS];
InvertQuantize invert_quantize[NB_SUBBANDS];
Prediction prediction[NB_SUBBANDS];
} Channel;
typedef struct {
int32_t sync_idx;
Channel channels[NB_CHANNELS];
AudioFrameQueue afq;
} AptXContext;
static const int32_t quantize_intervals_LF[65] = {
-9948, 9948, 29860, 49808, 69822, 89926, 110144, 130502,
151026, 171738, 192666, 213832, 235264, 256982, 279014, 301384,
324118, 347244, 370790, 394782, 419250, 444226, 469742, 495832,
522536, 549890, 577936, 606720, 636290, 666700, 698006, 730270,
763562, 797958, 833538, 870398, 908640, 948376, 989740, 1032874,
1077948, 1125150, 1174700, 1226850, 1281900, 1340196, 1402156, 1468282,
1539182, 1615610, 1698514, 1789098, 1888944, 2000168, 2125700, 2269750,
2438670, 2642660, 2899462, 3243240, 3746078, 4535138, 5664098, 7102424,
8897462,
};
static const int32_t invert_quantize_dither_factors_LF[65] = {
9948, 9948, 9962, 9988, 10026, 10078, 10142, 10218,
10306, 10408, 10520, 10646, 10784, 10934, 11098, 11274,
11462, 11664, 11880, 12112, 12358, 12618, 12898, 13194,
13510, 13844, 14202, 14582, 14988, 15422, 15884, 16380,
16912, 17484, 18098, 18762, 19480, 20258, 21106, 22030,
23044, 24158, 25390, 26760, 28290, 30008, 31954, 34172,
36728, 39700, 43202, 47382, 52462, 58762, 66770, 77280,
91642, 112348, 144452, 199326, 303512, 485546, 643414, 794914,
1000124,
};
static const int32_t quantize_dither_factors_LF[65] = {
0, 4, 7, 10, 13, 16, 19, 22,
26, 28, 32, 35, 38, 41, 44, 47,
51, 54, 58, 62, 65, 70, 74, 79,
84, 90, 95, 102, 109, 116, 124, 133,
143, 154, 166, 180, 195, 212, 231, 254,
279, 308, 343, 383, 430, 487, 555, 639,
743, 876, 1045, 1270, 1575, 2002, 2628, 3591,
5177, 8026, 13719, 26047, 45509, 39467, 37875, 51303,
0,
};
static const int16_t quantize_factor_select_offset_LF[65] = {
0, -21, -19, -17, -15, -12, -10, -8,
-6, -4, -1, 1, 3, 6, 8, 10,
13, 15, 18, 20, 23, 26, 29, 31,
34, 37, 40, 43, 47, 50, 53, 57,
60, 64, 68, 72, 76, 80, 85, 89,
94, 99, 105, 110, 116, 123, 129, 136,
144, 152, 161, 171, 182, 194, 207, 223,
241, 263, 291, 328, 382, 467, 522, 522,
522,
};
static const int32_t quantize_intervals_MLF[9] = {
-89806, 89806, 278502, 494338, 759442, 1113112, 1652322, 2720256, 5190186,
};
static const int32_t invert_quantize_dither_factors_MLF[9] = {
89806, 89806, 98890, 116946, 148158, 205512, 333698, 734236, 1735696,
};
static const int32_t quantize_dither_factors_MLF[9] = {
0, 2271, 4514, 7803, 14339, 32047, 100135, 250365, 0,
};
static const int16_t quantize_factor_select_offset_MLF[9] = {
0, -14, 6, 29, 58, 96, 154, 270, 521,
};
static const int32_t quantize_intervals_MHF[3] = {
-194080, 194080, 890562,
};
static const int32_t invert_quantize_dither_factors_MHF[3] = {
194080, 194080, 502402,
};
static const int32_t quantize_dither_factors_MHF[3] = {
0, 77081, 0,
};
static const int16_t quantize_factor_select_offset_MHF[3] = {
0, -33, 136,
};
static const int32_t quantize_intervals_HF[5] = {
-163006, 163006, 542708, 1120554, 2669238,
};
static const int32_t invert_quantize_dither_factors_HF[5] = {
163006, 163006, 216698, 361148, 1187538,
};
static const int32_t quantize_dither_factors_HF[5] = {
0, 13423, 36113, 206598, 0,
};
static const int16_t quantize_factor_select_offset_HF[5] = {
0, -8, 33, 95, 262,
};
typedef const struct {
const int32_t *quantize_intervals;
const int32_t *invert_quantize_dither_factors;
const int32_t *quantize_dither_factors;
const int16_t *quantize_factor_select_offset;
int tables_size;
int32_t quantized_bits;
int32_t prediction_order;
} ConstTables;
static ConstTables tables[NB_SUBBANDS] = {
[LF] = { quantize_intervals_LF,
invert_quantize_dither_factors_LF,
quantize_dither_factors_LF,
quantize_factor_select_offset_LF,
FF_ARRAY_ELEMS(quantize_intervals_LF),
7, 24 },
[MLF] = { quantize_intervals_MLF,
invert_quantize_dither_factors_MLF,
quantize_dither_factors_MLF,
quantize_factor_select_offset_MLF,
FF_ARRAY_ELEMS(quantize_intervals_MLF),
4, 12 },
[MHF] = { quantize_intervals_MHF,
invert_quantize_dither_factors_MHF,
quantize_dither_factors_MHF,
quantize_factor_select_offset_MHF,
FF_ARRAY_ELEMS(quantize_intervals_MHF),
2, 6 },
[HF] = { quantize_intervals_HF,
invert_quantize_dither_factors_HF,
quantize_dither_factors_HF,
quantize_factor_select_offset_HF,
FF_ARRAY_ELEMS(quantize_intervals_HF),
3, 12 },
};
static const int16_t quantization_factors[32] = {
2048, 2093, 2139, 2186, 2233, 2282, 2332, 2383,
2435, 2489, 2543, 2599, 2656, 2714, 2774, 2834,
2896, 2960, 3025, 3091, 3158, 3228, 3298, 3371,
3444, 3520, 3597, 3676, 3756, 3838, 3922, 4008,
};
/* Rounded right shift with optionnal clipping */
#define RSHIFT_SIZE(size) \
av_always_inline \
static int##size##_t rshift##size(int##size##_t value, int shift) \
{ \
int##size##_t rounding = (int##size##_t)1 << (shift - 1); \
int##size##_t mask = ((int##size##_t)1 << (shift + 1)) - 1; \
return ((value + rounding) >> shift) - ((value & mask) == rounding); \
} \
av_always_inline \
static int##size##_t rshift##size##_clip24(int##size##_t value, int shift) \
{ \
return av_clip_intp2(rshift##size(value, shift), 23); \
}
RSHIFT_SIZE(32)
RSHIFT_SIZE(64)
av_always_inline
static void aptx_update_codeword_history(Channel *channel)
{
int32_t cw = ((channel->quantize[0].quantized_sample & 3) << 0) +
((channel->quantize[1].quantized_sample & 2) << 1) +
((channel->quantize[2].quantized_sample & 1) << 3);
channel->codeword_history = (cw << 8) + (channel->codeword_history << 4);
}
static void aptx_generate_dither(Channel *channel)
{
int subband;
int64_t m;
int32_t d;
aptx_update_codeword_history(channel);
m = (int64_t)5184443 * (channel->codeword_history >> 7);
d = (m << 2) + (m >> 22);
for (subband = 0; subband < NB_SUBBANDS; subband++)
channel->dither[subband] = d << (23 - 5*subband);
channel->dither_parity = (d >> 25) & 1;
}
/*
* Convolution filter coefficients for the outer QMF of the QMF tree.
* The 2 sets are a mirror of each other.
*/
static const int32_t aptx_qmf_outer_coeffs[NB_FILTERS][FILTER_TAPS] = {
{
730, -413, -9611, 43626, -121026, 269973, -585547, 2801966,
697128, -160481, 27611, 8478, -10043, 3511, 688, -897,
},
{
-897, 688, 3511, -10043, 8478, 27611, -160481, 697128,
2801966, -585547, 269973, -121026, 43626, -9611, -413, 730,
},
};
/*
* Convolution filter coefficients for the inner QMF of the QMF tree.
* The 2 sets are a mirror of each other.
*/
static const int32_t aptx_qmf_inner_coeffs[NB_FILTERS][FILTER_TAPS] = {
{
1033, -584, -13592, 61697, -171156, 381799, -828088, 3962579,
985888, -226954, 39048, 11990, -14203, 4966, 973, -1268,
},
{
-1268, 973, 4966, -14203, 11990, 39048, -226954, 985888,
3962579, -828088, 381799, -171156, 61697, -13592, -584, 1033,
},
};
/*
* Push one sample into a circular signal buffer.
*/
av_always_inline
static void aptx_qmf_filter_signal_push(FilterSignal *signal, int32_t sample)
{
signal->buffer[signal->pos ] = sample;
signal->buffer[signal->pos+FILTER_TAPS] = sample;
signal->pos = (signal->pos + 1) & (FILTER_TAPS - 1);
}
/*
* Compute the convolution of the signal with the coefficients, and reduce
* to 24 bits by applying the specified right shifting.
*/
av_always_inline
static int32_t aptx_qmf_convolution(FilterSignal *signal,
const int32_t coeffs[FILTER_TAPS],
int shift)
{
int32_t *sig = &signal->buffer[signal->pos];
int64_t e = 0;
int i;
for (i = 0; i < FILTER_TAPS; i++)
e += MUL64(sig[i], coeffs[i]);
return rshift64_clip24(e, shift);
}
/*
* Half-band QMF analysis filter realized with a polyphase FIR filter.
* Split into 2 subbands and downsample by 2.
* So for each pair of samples that goes in, one sample goes out,
* split into 2 separate subbands.
*/
av_always_inline
static void aptx_qmf_polyphase_analysis(FilterSignal signal[NB_FILTERS],
const int32_t coeffs[NB_FILTERS][FILTER_TAPS],
int shift,
int32_t samples[NB_FILTERS],
int32_t *low_subband_output,
int32_t *high_subband_output)
{
int32_t subbands[NB_FILTERS];
int i;
for (i = 0; i < NB_FILTERS; i++) {
aptx_qmf_filter_signal_push(&signal[i], samples[NB_FILTERS-1-i]);
subbands[i] = aptx_qmf_convolution(&signal[i], coeffs[i], shift);
}
*low_subband_output = av_clip_intp2(subbands[0] + subbands[1], 23);
*high_subband_output = av_clip_intp2(subbands[0] - subbands[1], 23);
}
/*
* Two stage QMF analysis tree.
* Split 4 input samples into 4 subbands and downsample by 4.
* So for each group of 4 samples that goes in, one sample goes out,
* split into 4 separate subbands.
*/
static void aptx_qmf_tree_analysis(QMFAnalysis *qmf,
int32_t samples[4],
int32_t subband_samples[4])
{
int32_t intermediate_samples[4];
int i;
/* Split 4 input samples into 2 intermediate subbands downsampled to 2 samples */
for (i = 0; i < 2; i++)
aptx_qmf_polyphase_analysis(qmf->outer_filter_signal,
aptx_qmf_outer_coeffs, 23,
&samples[2*i],
&intermediate_samples[0+i],
&intermediate_samples[2+i]);
/* Split 2 intermediate subband samples into 4 final subbands downsampled to 1 sample */
for (i = 0; i < 2; i++)
aptx_qmf_polyphase_analysis(qmf->inner_filter_signal[i],
aptx_qmf_inner_coeffs, 23,
&intermediate_samples[2*i],
&subband_samples[2*i+0],
&subband_samples[2*i+1]);
}
/*
* Half-band QMF synthesis filter realized with a polyphase FIR filter.
* Join 2 subbands and upsample by 2.
* So for each 2 subbands sample that goes in, a pair of samples goes out.
*/
av_always_inline
static void aptx_qmf_polyphase_synthesis(FilterSignal signal[NB_FILTERS],
const int32_t coeffs[NB_FILTERS][FILTER_TAPS],
int shift,
int32_t low_subband_input,
int32_t high_subband_input,
int32_t samples[NB_FILTERS])
{
int32_t subbands[NB_FILTERS];
int i;
subbands[0] = low_subband_input + high_subband_input;
subbands[1] = low_subband_input - high_subband_input;
for (i = 0; i < NB_FILTERS; i++) {
aptx_qmf_filter_signal_push(&signal[i], subbands[1-i]);
samples[i] = aptx_qmf_convolution(&signal[i], coeffs[i], shift);
}
}
/*
* Two stage QMF synthesis tree.
* Join 4 subbands and upsample by 4.
* So for each 4 subbands sample that goes in, a group of 4 samples goes out.
*/
static void aptx_qmf_tree_synthesis(QMFAnalysis *qmf,
int32_t subband_samples[4],
int32_t samples[4])
{
int32_t intermediate_samples[4];
int i;
/* Join 4 subbands into 2 intermediate subbands upsampled to 2 samples. */
for (i = 0; i < 2; i++)
aptx_qmf_polyphase_synthesis(qmf->inner_filter_signal[i],
aptx_qmf_inner_coeffs, 22,
subband_samples[2*i+0],
subband_samples[2*i+1],
&intermediate_samples[2*i]);
/* Join 2 samples from intermediate subbands upsampled to 4 samples. */
for (i = 0; i < 2; i++)
aptx_qmf_polyphase_synthesis(qmf->outer_filter_signal,
aptx_qmf_outer_coeffs, 21,
intermediate_samples[0+i],
intermediate_samples[2+i],
&samples[2*i]);
}
av_always_inline
static int32_t aptx_bin_search(int32_t value, int32_t factor,
const int32_t *intervals, int32_t nb_intervals)
{
int32_t idx = 0;
int i;
for (i = nb_intervals >> 1; i > 0; i >>= 1)
if (MUL64(factor, intervals[idx + i]) <= ((int64_t)value << 24))
idx += i;
return idx;
}
static void aptx_quantize_difference(Quantize *quantize,
int32_t sample_difference,
int32_t dither,
int32_t quantization_factor,
ConstTables *tables)
{
const int32_t *intervals = tables->quantize_intervals;
int32_t quantized_sample, dithered_sample, parity_change;
int32_t d, mean, interval, inv;
int64_t error;
quantized_sample = aptx_bin_search(FFABS(sample_difference) >> 4,
quantization_factor,
intervals, tables->tables_size);
d = rshift32_clip24(MULH(dither, dither), 7) - (1 << 23);
d = rshift64(MUL64(d, tables->quantize_dither_factors[quantized_sample]), 23);
intervals += quantized_sample;
mean = (intervals[1] + intervals[0]) / 2;
interval = (intervals[1] - intervals[0]) * (-(sample_difference < 0) | 1);
dithered_sample = rshift64_clip24(MUL64(dither, interval) + ((int64_t)(mean + d) << 32), 32);
error = ((int64_t)FFABS(sample_difference) << 20) - MUL64(dithered_sample, quantization_factor);
quantize->error = FFABS(rshift64(error, 23));
parity_change = quantized_sample;
if (error < 0)
quantized_sample--;
else
parity_change--;
inv = -(sample_difference < 0);
quantize->quantized_sample = quantized_sample ^ inv;
quantize->quantized_sample_parity_change = parity_change ^ inv;
}
static void aptx_encode_channel(Channel *channel, int32_t samples[4])
{
int32_t subband_samples[4];
int subband;
aptx_qmf_tree_analysis(&channel->qmf, samples, subband_samples);
aptx_generate_dither(channel);
for (subband = 0; subband < NB_SUBBANDS; subband++) {
int32_t diff = av_clip_intp2(subband_samples[subband] - channel->prediction[subband].predicted_sample, 23);
aptx_quantize_difference(&channel->quantize[subband], diff,
channel->dither[subband],
channel->invert_quantize[subband].quantization_factor,
&tables[subband]);
}
}
static void aptx_decode_channel(Channel *channel, int32_t samples[4])
{
int32_t subband_samples[4];
int subband;
for (subband = 0; subband < NB_SUBBANDS; subband++)
subband_samples[subband] = channel->prediction[subband].previous_reconstructed_sample;
aptx_qmf_tree_synthesis(&channel->qmf, subband_samples, samples);
}
static void aptx_invert_quantization(InvertQuantize *invert_quantize,
int32_t quantized_sample, int32_t dither,
ConstTables *tables)
{
int32_t qr, idx, shift, factor_select;
idx = (quantized_sample ^ -(quantized_sample < 0)) + 1;
qr = tables->quantize_intervals[idx] / 2;
if (quantized_sample < 0)
qr = -qr;
qr = rshift64_clip24(((int64_t)qr<<32) + MUL64(dither, tables->invert_quantize_dither_factors[idx]), 32);
invert_quantize->reconstructed_difference = MUL64(invert_quantize->quantization_factor, qr) >> 19;
shift = 24 - tables->quantized_bits;
/* update factor_select */
factor_select = 32620 * invert_quantize->factor_select;
factor_select = rshift32(factor_select + (tables->quantize_factor_select_offset[idx] << 15), 15);
invert_quantize->factor_select = av_clip(factor_select, 0, (shift << 8) | 0xFF);
/* update quantization factor */
idx = (invert_quantize->factor_select & 0xFF) >> 3;
shift -= invert_quantize->factor_select >> 8;
invert_quantize->quantization_factor = (quantization_factors[idx] << 11) >> shift;
}
static int32_t *aptx_reconstructed_differences_update(Prediction *prediction,
int32_t reconstructed_difference,
int order)
{
int32_t *rd1 = prediction->reconstructed_differences, *rd2 = rd1 + order;
int p = prediction->pos;
rd1[p] = rd2[p];
prediction->pos = p = (p + 1) % order;
rd2[p] = reconstructed_difference;
return &rd2[p];
}
static void aptx_prediction_filtering(Prediction *prediction,
int32_t reconstructed_difference,
int order)
{
int32_t reconstructed_sample, predictor, srd0;
int32_t *reconstructed_differences;
int64_t predicted_difference = 0;
int i;
reconstructed_sample = av_clip_intp2(reconstructed_difference + prediction->predicted_sample, 23);
predictor = av_clip_intp2((MUL64(prediction->s_weight[0], prediction->previous_reconstructed_sample)
+ MUL64(prediction->s_weight[1], reconstructed_sample)) >> 22, 23);
prediction->previous_reconstructed_sample = reconstructed_sample;
reconstructed_differences = aptx_reconstructed_differences_update(prediction, reconstructed_difference, order);
srd0 = FFDIFFSIGN(reconstructed_difference, 0) << 23;
for (i = 0; i < order; i++) {
int32_t srd = FF_SIGNBIT(reconstructed_differences[-i-1]) | 1;
prediction->d_weight[i] -= rshift32(prediction->d_weight[i] - srd*srd0, 8);
predicted_difference += MUL64(reconstructed_differences[-i], prediction->d_weight[i]);
}
prediction->predicted_difference = av_clip_intp2(predicted_difference >> 22, 23);
prediction->predicted_sample = av_clip_intp2(predictor + prediction->predicted_difference, 23);
}
static void aptx_process_subband(InvertQuantize *invert_quantize,
Prediction *prediction,
int32_t quantized_sample, int32_t dither,
ConstTables *tables)
{
int32_t sign, same_sign[2], weight[2], sw1, range;
aptx_invert_quantization(invert_quantize, quantized_sample, dither, tables);
sign = FFDIFFSIGN(invert_quantize->reconstructed_difference,
-prediction->predicted_difference);
same_sign[0] = sign * prediction->prev_sign[0];
same_sign[1] = sign * prediction->prev_sign[1];
prediction->prev_sign[0] = prediction->prev_sign[1];
prediction->prev_sign[1] = sign | 1;
range = 0x100000;
sw1 = rshift32(-same_sign[1] * prediction->s_weight[1], 1);
sw1 = (av_clip(sw1, -range, range) & ~0xF) << 4;
range = 0x300000;
weight[0] = 254 * prediction->s_weight[0] + 0x800000*same_sign[0] + sw1;
prediction->s_weight[0] = av_clip(rshift32(weight[0], 8), -range, range);
range = 0x3C0000 - prediction->s_weight[0];
weight[1] = 255 * prediction->s_weight[1] + 0xC00000*same_sign[1];
prediction->s_weight[1] = av_clip(rshift32(weight[1], 8), -range, range);
aptx_prediction_filtering(prediction,
invert_quantize->reconstructed_difference,
tables->prediction_order);
}
static void aptx_invert_quantize_and_prediction(Channel *channel)
{
int subband;
for (subband = 0; subband < NB_SUBBANDS; subband++)
aptx_process_subband(&channel->invert_quantize[subband],
&channel->prediction[subband],
channel->quantize[subband].quantized_sample,
channel->dither[subband],
&tables[subband]);
}
static int32_t aptx_quantized_parity(Channel *channel)
{
int32_t parity = channel->dither_parity;
int subband;
for (subband = 0; subband < NB_SUBBANDS; subband++)
parity ^= channel->quantize[subband].quantized_sample;
return parity & 1;
}
/* For each sample, ensure that the parity of all subbands of all channels
* is 0 except once every 8 samples where the parity is forced to 1. */
static int aptx_check_parity(Channel channels[NB_CHANNELS], int32_t *idx)
{
int32_t parity = aptx_quantized_parity(&channels[LEFT])
^ aptx_quantized_parity(&channels[RIGHT]);
int eighth = *idx == 7;
*idx = (*idx + 1) & 7;
return parity ^ eighth;
}
static void aptx_insert_sync(Channel channels[NB_CHANNELS], int32_t *idx)
{
if (aptx_check_parity(channels, idx)) {
int i;
Channel *c;
static const int map[] = { 1, 2, 0, 3 };
Quantize *min = &channels[NB_CHANNELS-1].quantize[map[0]];
for (c = &channels[NB_CHANNELS-1]; c >= channels; c--)
for (i = 0; i < NB_SUBBANDS; i++)
if (c->quantize[map[i]].error < min->error)
min = &c->quantize[map[i]];
/* Forcing the desired parity is done by offsetting by 1 the quantized
* sample from the subband featuring the smallest quantization error. */
min->quantized_sample = min->quantized_sample_parity_change;
}
}
static uint16_t aptx_pack_codeword(Channel *channel)
{
int32_t parity = aptx_quantized_parity(channel);
return (((channel->quantize[3].quantized_sample & 0x06) | parity) << 13)
| (((channel->quantize[2].quantized_sample & 0x03) ) << 11)
| (((channel->quantize[1].quantized_sample & 0x0F) ) << 7)
| (((channel->quantize[0].quantized_sample & 0x7F) ) << 0);
}
static void aptx_unpack_codeword(Channel *channel, uint16_t codeword)
{
channel->quantize[0].quantized_sample = sign_extend(codeword >> 0, 7);
channel->quantize[1].quantized_sample = sign_extend(codeword >> 7, 4);
channel->quantize[2].quantized_sample = sign_extend(codeword >> 11, 2);
channel->quantize[3].quantized_sample = sign_extend(codeword >> 13, 3);
channel->quantize[3].quantized_sample = (channel->quantize[3].quantized_sample & ~1)
| aptx_quantized_parity(channel);
}
static void aptx_encode_samples(AptXContext *ctx,
int32_t samples[NB_CHANNELS][4],
uint8_t output[2*NB_CHANNELS])
{
int channel;
for (channel = 0; channel < NB_CHANNELS; channel++)
aptx_encode_channel(&ctx->channels[channel], samples[channel]);
aptx_insert_sync(ctx->channels, &ctx->sync_idx);
for (channel = 0; channel < NB_CHANNELS; channel++) {
aptx_invert_quantize_and_prediction(&ctx->channels[channel]);
AV_WB16(output + 2*channel, aptx_pack_codeword(&ctx->channels[channel]));
}
}
static int aptx_decode_samples(AptXContext *ctx,
const uint8_t input[2*NB_CHANNELS],
int32_t samples[NB_CHANNELS][4])
{
int channel, ret;
for (channel = 0; channel < NB_CHANNELS; channel++) {
uint16_t codeword;
aptx_generate_dither(&ctx->channels[channel]);
codeword = AV_RB16(input + 2*channel);
aptx_unpack_codeword(&ctx->channels[channel], codeword);
aptx_invert_quantize_and_prediction(&ctx->channels[channel]);
}
ret = aptx_check_parity(ctx->channels, &ctx->sync_idx);
for (channel = 0; channel < NB_CHANNELS; channel++)
aptx_decode_channel(&ctx->channels[channel], samples[channel]);
return ret;
}
static av_cold int aptx_init(AVCodecContext *avctx)
{
AptXContext *s = avctx->priv_data;
int chan, subband;
if (avctx->frame_size == 0)
avctx->frame_size = 1024;
if (avctx->frame_size & 3) {
av_log(avctx, AV_LOG_ERROR, "Frame size must be a multiple of 4 samples\n");
return AVERROR(EINVAL);
}
for (chan = 0; chan < NB_CHANNELS; chan++) {
Channel *channel = &s->channels[chan];
for (subband = 0; subband < NB_SUBBANDS; subband++) {
Prediction *prediction = &channel->prediction[subband];
prediction->prev_sign[0] = 1;
prediction->prev_sign[1] = 1;
}
}
ff_af_queue_init(avctx, &s->afq);
return 0;
}
static int aptx_decode_frame(AVCodecContext *avctx, void *data,
int *got_frame_ptr, AVPacket *avpkt)
{
AptXContext *s = avctx->priv_data;
AVFrame *frame = data;
int pos, channel, sample, ret;
if (avpkt->size < 4) {
av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
return AVERROR_INVALIDDATA;
}
/* get output buffer */
frame->channels = NB_CHANNELS;
frame->format = AV_SAMPLE_FMT_S32P;
frame->nb_samples = avpkt->size & ~3;
if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
return ret;
for (pos = 0; pos < frame->nb_samples; pos += 4) {
int32_t samples[NB_CHANNELS][4];
if (aptx_decode_samples(s, &avpkt->data[pos], samples)) {
av_log(avctx, AV_LOG_ERROR, "Synchronization error\n");
return AVERROR_INVALIDDATA;
}
for (channel = 0; channel < NB_CHANNELS; channel++)
for (sample = 0; sample < 4; sample++)
AV_WN32A(&frame->data[channel][4*(sample+pos)],
samples[channel][sample] << 8);
}
*got_frame_ptr = 1;
return frame->nb_samples;
}
static int aptx_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
const AVFrame *frame, int *got_packet_ptr)
{
AptXContext *s = avctx->priv_data;
int pos, channel, sample, ret;
if ((ret = ff_af_queue_add(&s->afq, frame)) < 0)
return ret;
if ((ret = ff_alloc_packet2(avctx, avpkt, frame->nb_samples, 0)) < 0)
return ret;
for (pos = 0; pos < frame->nb_samples; pos += 4) {
int32_t samples[NB_CHANNELS][4];
for (channel = 0; channel < NB_CHANNELS; channel++)
for (sample = 0; sample < 4; sample++)
samples[channel][sample] = (int32_t)AV_RN32A(&frame->data[channel][4*(sample+pos)]) >> 8;
aptx_encode_samples(s, samples, avpkt->data + pos);
}
ff_af_queue_remove(&s->afq, frame->nb_samples, &avpkt->pts, &avpkt->duration);
*got_packet_ptr = 1;
return 0;
}
static av_cold int aptx_close(AVCodecContext *avctx)
{
AptXContext *s = avctx->priv_data;
ff_af_queue_close(&s->afq);
return 0;
}
#if CONFIG_APTX_DECODER
AVCodec ff_aptx_decoder = {
.name = "aptx",
.long_name = NULL_IF_CONFIG_SMALL("aptX (Audio Processing Technology for Bluetooth)"),
.type = AVMEDIA_TYPE_AUDIO,
.id = AV_CODEC_ID_APTX,
.priv_data_size = sizeof(AptXContext),
.init = aptx_init,
.decode = aptx_decode_frame,
.close = aptx_close,
.capabilities = AV_CODEC_CAP_DR1,
.channel_layouts = (const uint64_t[]) { AV_CH_LAYOUT_STEREO, 0},
.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S32P,
AV_SAMPLE_FMT_NONE },
};
#endif
#if CONFIG_APTX_ENCODER
AVCodec ff_aptx_encoder = {
.name = "aptx",
.long_name = NULL_IF_CONFIG_SMALL("aptX (Audio Processing Technology for Bluetooth)"),
.type = AVMEDIA_TYPE_AUDIO,
.id = AV_CODEC_ID_APTX,
.priv_data_size = sizeof(AptXContext),
.init = aptx_init,
.encode2 = aptx_encode_frame,
.close = aptx_close,
.channel_layouts = (const uint64_t[]) { AV_CH_LAYOUT_STEREO, 0},
.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S32P,
AV_SAMPLE_FMT_NONE },
.supported_samplerates = (const int[]) {8000, 16000, 24000, 32000, 44100, 48000, 0},
};
#endif

1
libavcodec/avcodec.h
View File

@ -632,6 +632,7 @@ enum AVCodecID {
AV_CODEC_ID_ATRAC3AL,
AV_CODEC_ID_ATRAC3PAL,
AV_CODEC_ID_DOLBY_E,
AV_CODEC_ID_APTX,
/* subtitle codecs */
AV_CODEC_ID_FIRST_SUBTITLE = 0x17000, ///< A dummy ID pointing at the start of subtitle codecs.

7
libavcodec/codec_desc.c
View File

@ -2859,6 +2859,13 @@ static const AVCodecDescriptor codec_descriptors[] = {
.long_name = NULL_IF_CONFIG_SMALL("ADPCM MTAF"),
.props = AV_CODEC_PROP_LOSSY,
},
{
.id = AV_CODEC_ID_APTX,
.type = AVMEDIA_TYPE_AUDIO,
.name = "aptx",
.long_name = NULL_IF_CONFIG_SMALL("aptX (Audio Processing Technology for Bluetooth)"),
.props = AV_CODEC_PROP_LOSSY,
},
/* subtitle codecs */
{