FFmpeg
aptx.h
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1 /*
2  * Audio Processing Technology codec for Bluetooth (aptX)
3  *
4  * Copyright (C) 2017 Aurelien Jacobs <aurel@gnuage.org>
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 #ifndef AVCODEC_APTX_H
24 #define AVCODEC_APTX_H
25 
26 #include "libavutil/intreadwrite.h"
27 #include "avcodec.h"
28 #include "internal.h"
29 #include "mathops.h"
30 #include "audio_frame_queue.h"
31 
32 
33 enum channels {
37 };
38 
39 enum subbands {
40  LF, // Low Frequency (0-5.5 kHz)
41  MLF, // Medium-Low Frequency (5.5-11kHz)
42  MHF, // Medium-High Frequency (11-16.5kHz)
43  HF, // High Frequency (16.5-22kHz)
45 };
46 
47 #define NB_FILTERS 2
48 #define FILTER_TAPS 16
49 
50 typedef struct {
51  int pos;
53 } FilterSignal;
54 
55 typedef struct {
56  FilterSignal outer_filter_signal[NB_FILTERS];
57  FilterSignal inner_filter_signal[NB_FILTERS][NB_FILTERS];
58 } QMFAnalysis;
59 
60 typedef struct {
64 } Quantize;
65 
66 typedef struct {
71 
72 typedef struct {
73  int32_t prev_sign[2];
74  int32_t s_weight[2];
75  int32_t d_weight[24];
77  int32_t reconstructed_differences[48];
81 } Prediction;
82 
83 typedef struct {
87 
90  InvertQuantize invert_quantize[NB_SUBBANDS];
91  Prediction prediction[NB_SUBBANDS];
92 } Channel;
93 
94 typedef struct {
95  int hd;
100 } AptXContext;
101 
102 typedef const struct {
110 } ConstTables;
111 
113 
114 /* Rounded right shift with optionnal clipping */
115 #define RSHIFT_SIZE(size) \
116 av_always_inline \
117 static int##size##_t rshift##size(int##size##_t value, int shift) \
118 { \
119  int##size##_t rounding = (int##size##_t)1 << (shift - 1); \
120  int##size##_t mask = ((int##size##_t)1 << (shift + 1)) - 1; \
121  return ((value + rounding) >> shift) - ((value & mask) == rounding); \
122 } \
123 av_always_inline \
124 static int##size##_t rshift##size##_clip24(int##size##_t value, int shift) \
125 { \
126  return av_clip_intp2(rshift##size(value, shift), 23); \
127 }
128 RSHIFT_SIZE(32)
129 RSHIFT_SIZE(64)
130 
131 /*
132  * Convolution filter coefficients for the outer QMF of the QMF tree.
133  * The 2 sets are a mirror of each other.
134  */
136  {
137  730, -413, -9611, 43626, -121026, 269973, -585547, 2801966,
138  697128, -160481, 27611, 8478, -10043, 3511, 688, -897,
139  },
140  {
141  -897, 688, 3511, -10043, 8478, 27611, -160481, 697128,
142  2801966, -585547, 269973, -121026, 43626, -9611, -413, 730,
143  },
144 };
145 
146 /*
147  * Convolution filter coefficients for the inner QMF of the QMF tree.
148  * The 2 sets are a mirror of each other.
149  */
151  {
152  1033, -584, -13592, 61697, -171156, 381799, -828088, 3962579,
153  985888, -226954, 39048, 11990, -14203, 4966, 973, -1268,
154  },
155  {
156  -1268, 973, 4966, -14203, 11990, 39048, -226954, 985888,
157  3962579, -828088, 381799, -171156, 61697, -13592, -584, 1033,
158  },
159 };
160 
161 /*
162  * Push one sample into a circular signal buffer.
163  */
166 {
167  signal->buffer[signal->pos ] = sample;
168  signal->buffer[signal->pos+FILTER_TAPS] = sample;
169  signal->pos = (signal->pos + 1) & (FILTER_TAPS - 1);
170 }
171 
172 /*
173  * Compute the convolution of the signal with the coefficients, and reduce
174  * to 24 bits by applying the specified right shifting.
175  */
178  const int32_t coeffs[FILTER_TAPS],
179  int shift)
180 {
181  int32_t *sig = &signal->buffer[signal->pos];
182  int64_t e = 0;
183  int i;
184 
185  for (i = 0; i < FILTER_TAPS; i++)
186  e += MUL64(sig[i], coeffs[i]);
187 
188  return rshift64_clip24(e, shift);
189 }
190 
192 {
193  int32_t parity = channel->dither_parity;
194  int subband;
195 
196  for (subband = 0; subband < NB_SUBBANDS; subband++)
197  parity ^= channel->quantize[subband].quantized_sample;
198 
199  return parity & 1;
200 }
201 
202 /* For each sample, ensure that the parity of all subbands of all channels
203  * is 0 except once every 8 samples where the parity is forced to 1. */
205 {
208 
209  int eighth = *idx == 7;
210  *idx = (*idx + 1) & 7;
211 
212  return parity ^ eighth;
213 }
214 
216 void ff_aptx_generate_dither(Channel *channel);
217 
219 
220 #endif /* AVCODEC_APTX_H */
#define MUL64(a, b)
Definition: mathops.h:54
static int shift(int a, int b)
Definition: sonic.c:82
int32_t reconstructed_difference
Definition: aptx.h:69
int block_size
Definition: aptx.h:96
Definition: aptx.h:42
static av_always_inline int32_t aptx_qmf_convolution(FilterSignal *signal, const int32_t coeffs[FILTER_TAPS], int shift)
Definition: aptx.h:177
#define sample
Definition: aptx.h:83
const int32_t * quantize_dither_factors
Definition: aptx.h:105
int32_t dither_parity
Definition: aptx.h:85
static av_always_inline void aptx_qmf_filter_signal_push(FilterSignal *signal, int32_t sample)
Definition: aptx.h:165
static int32_t aptx_quantized_parity(Channel *channel)
Definition: aptx.h:191
int32_t codeword_history
Definition: aptx.h:84
const int16_t * quantize_factor_select_offset
Definition: aptx.h:106
Definition: aptx.h:41
Quantize quantize[NB_SUBBANDS]
Definition: aptx.h:89
static const int32_t aptx_qmf_inner_coeffs[NB_FILTERS][FILTER_TAPS]
Definition: aptx.h:150
Prediction
Definition: magicyuv.c:41
static const int32_t aptx_qmf_outer_coeffs[NB_FILTERS][FILTER_TAPS]
Definition: aptx.h:135
int32_t sync_idx
Definition: aptx.h:97
int hd
Definition: aptx.h:95
channels
Definition: aptx.h:33
int32_t predicted_sample
Definition: aptx.h:80
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:259
static const uint8_t dither[8][8]
Definition: vf_fspp.c:57
int32_t pos
Definition: aptx.h:76
Definition: aptx.h:40
QMFAnalysis qmf
Definition: aptx.h:88
int32_t quantized_sample_parity_change
Definition: aptx.h:62
int32_t quantization_factor
Definition: aptx.h:67
subbands
Definition: aptx.h:39
AVCodecContext * avctx
Definition: apedec.c:138
int32_t
mcdeint parity
Definition: vf_mcdeint.c:274
Definition: aptx.h:35
int32_t previous_reconstructed_sample
Definition: aptx.h:78
int32_t error
Definition: aptx.h:63
int32_t quantized_sample
Definition: aptx.h:61
Definition: aptx.h:43
Libavcodec external API header.
const int32_t * invert_quantize_dither_factors
Definition: aptx.h:104
main external API structure.
Definition: avcodec.h:1621
AudioFrameQueue afq
Definition: aptx.h:99
int tables_size
Definition: aptx.h:107
static int aptx_check_parity(Channel channels[NB_CHANNELS], int32_t *idx)
Definition: aptx.h:204
int ff_aptx_init(AVCodecContext *avctx)
Definition: aptx.c:507
void ff_aptx_generate_dither(Channel *channel)
Definition: aptx.c:384
Definition: aptx.h:34
common internal api header.
#define NB_FILTERS
Definition: aptx.h:47
channel
Use these values when setting the channel map with ebur128_set_channel().
Definition: ebur128.h:39
int32_t factor_select
Definition: aptx.h:68
const int32_t * quantize_intervals
Definition: aptx.h:103
static int quantize(CinepakEncContext *s, int h, uint8_t *data[4], int linesize[4], int v1mode, strip_info *info, mb_encoding encoding)
Definition: cinepakenc.c:715
int32_t prediction_order
Definition: aptx.h:109
ConstTables ff_aptx_quant_tables[2][NB_SUBBANDS]
Definition: aptx.c:312
int pos
Definition: aptx.h:51
#define FILTER_TAPS
Definition: aptx.h:48
#define RSHIFT_SIZE(size)
Definition: aptx.h:115
int32_t factor_max
Definition: aptx.h:108
#define av_always_inline
Definition: attributes.h:39
void ff_aptx_invert_quantize_and_prediction(Channel *channel, int hd)
Definition: aptx.c:496
Definition: aptx.h:60
int32_t predicted_difference
Definition: aptx.h:79
int32_t buffer[2 *FILTER_TAPS]
Definition: aptx.h:52
GLuint buffer
Definition: opengl_enc.c:101