FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/aptx.h
Date: 2022-11-28 23:49:43
Exec Total Coverage
Lines: 24 24 100.0%
Branches: 4 4 100.0%

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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 "mathops.h"
29
30
31 enum channels {
32 LEFT,
33 RIGHT,
34 NB_CHANNELS
35 };
36
37 enum subbands {
38 LF, // Low Frequency (0-5.5 kHz)
39 MLF, // Medium-Low Frequency (5.5-11kHz)
40 MHF, // Medium-High Frequency (11-16.5kHz)
41 HF, // High Frequency (16.5-22kHz)
42 NB_SUBBANDS
43 };
44
45 #define NB_FILTERS 2
46 #define FILTER_TAPS 16
47
48 typedef struct {
49 int pos;
50 int32_t buffer[2*FILTER_TAPS];
51 } FilterSignal;
52
53 typedef struct {
54 FilterSignal outer_filter_signal[NB_FILTERS];
55 FilterSignal inner_filter_signal[NB_FILTERS][NB_FILTERS];
56 } QMFAnalysis;
57
58 typedef struct {
59 int32_t quantized_sample;
60 int32_t quantized_sample_parity_change;
61 int32_t error;
62 } Quantize;
63
64 typedef struct {
65 int32_t quantization_factor;
66 int32_t factor_select;
67 int32_t reconstructed_difference;
68 } InvertQuantize;
69
70 typedef struct {
71 int32_t prev_sign[2];
72 int32_t s_weight[2];
73 int32_t d_weight[24];
74 int32_t pos;
75 int32_t reconstructed_differences[48];
76 int32_t previous_reconstructed_sample;
77 int32_t predicted_difference;
78 int32_t predicted_sample;
79 } Prediction;
80
81 typedef struct {
82 int32_t codeword_history;
83 int32_t dither_parity;
84 int32_t dither[NB_SUBBANDS];
85
86 QMFAnalysis qmf;
87 Quantize quantize[NB_SUBBANDS];
88 InvertQuantize invert_quantize[NB_SUBBANDS];
89 Prediction prediction[NB_SUBBANDS];
90 } Channel;
91
92 typedef struct {
93 int hd;
94 int block_size;
95 int32_t sync_idx;
96 Channel channels[NB_CHANNELS];
97 } AptXContext;
98
99 typedef const struct {
100 const int32_t *quantize_intervals;
101 const int32_t *invert_quantize_dither_factors;
102 const int32_t *quantize_dither_factors;
103 const int16_t *quantize_factor_select_offset;
104 int tables_size;
105 int32_t factor_max;
106 int32_t prediction_order;
107 } ConstTables;
108
109 extern ConstTables ff_aptx_quant_tables[2][NB_SUBBANDS];
110
111 /* Rounded right shift with optionnal clipping */
112 #define RSHIFT_SIZE(size) \
113 av_always_inline \
114 static int##size##_t rshift##size(int##size##_t value, int shift) \
115 { \
116 int##size##_t rounding = (int##size##_t)1 << (shift - 1); \
117 int##size##_t mask = ((int##size##_t)1 << (shift + 1)) - 1; \
118 return ((value + rounding) >> shift) - ((value & mask) == rounding); \
119 } \
120 av_always_inline \
121 static int##size##_t rshift##size##_clip24(int##size##_t value, int shift) \
122 { \
123 return av_clip_intp2(rshift##size(value, shift), 23); \
124 }
125 36890032 RSHIFT_SIZE(32)
126 22375328 RSHIFT_SIZE(64)
127
128 /*
129 * Convolution filter coefficients for the outer QMF of the QMF tree.
130 * The 2 sets are a mirror of each other.
131 */
132 static const int32_t aptx_qmf_outer_coeffs[NB_FILTERS][FILTER_TAPS] = {
133 {
134 730, -413, -9611, 43626, -121026, 269973, -585547, 2801966,
135 697128, -160481, 27611, 8478, -10043, 3511, 688, -897,
136 },
137 {
138 -897, 688, 3511, -10043, 8478, 27611, -160481, 697128,
139 2801966, -585547, 269973, -121026, 43626, -9611, -413, 730,
140 },
141 };
142
143 /*
144 * Convolution filter coefficients for the inner QMF of the QMF tree.
145 * The 2 sets are a mirror of each other.
146 */
147 static const int32_t aptx_qmf_inner_coeffs[NB_FILTERS][FILTER_TAPS] = {
148 {
149 1033, -584, -13592, 61697, -171156, 381799, -828088, 3962579,
150 985888, -226954, 39048, 11990, -14203, 4966, 973, -1268,
151 },
152 {
153 -1268, 973, 4966, -14203, 11990, 39048, -226954, 985888,
154 3962579, -828088, 381799, -171156, 61697, -13592, -584, 1033,
155 },
156 };
157
158 /*
159 * Push one sample into a circular signal buffer.
160 */
161 av_always_inline
162 3449920 static void aptx_qmf_filter_signal_push(FilterSignal *signal, int32_t sample)
163 {
164 3449920 signal->buffer[signal->pos ] = sample;
165 3449920 signal->buffer[signal->pos+FILTER_TAPS] = sample;
166 3449920 signal->pos = (signal->pos + 1) & (FILTER_TAPS - 1);
167 3449920 }
168
169 /*
170 * Compute the convolution of the signal with the coefficients, and reduce
171 * to 24 bits by applying the specified right shifting.
172 */
173 av_always_inline
174 3449920 static int32_t aptx_qmf_convolution(FilterSignal *signal,
175 const int32_t coeffs[FILTER_TAPS],
176 int shift)
177 {
178 3449920 int32_t *sig = &signal->buffer[signal->pos];
179 3449920 int64_t e = 0;
180 int i;
181
182
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58648640 for (i = 0; i < FILTER_TAPS; i++)
183 55198720 e += MUL64(sig[i], coeffs[i]);
184
185 3449920 return rshift64_clip24(e, shift);
186 }
187
188 1281432 static inline int32_t aptx_quantized_parity(Channel *channel)
189 {
190 1281432 int32_t parity = channel->dither_parity;
191 int subband;
192
193
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6407160 for (subband = 0; subband < NB_SUBBANDS; subband++)
194 5125728 parity ^= channel->quantize[subband].quantized_sample;
195
196 1281432 return parity & 1;
197 }
198
199 /* For each sample, ensure that the parity of all subbands of all channels
200 * is 0 except once every 8 samples where the parity is forced to 1. */
201 215620 static inline int aptx_check_parity(Channel channels[NB_CHANNELS], int32_t *idx)
202 {
203 215620 int32_t parity = aptx_quantized_parity(&channels[LEFT])
204 215620 ^ aptx_quantized_parity(&channels[RIGHT]);
205
206 215620 int eighth = *idx == 7;
207 215620 *idx = (*idx + 1) & 7;
208
209 215620 return parity ^ eighth;
210 }
211
212 void ff_aptx_invert_quantize_and_prediction(Channel *channel, int hd);
213 void ff_aptx_generate_dither(Channel *channel);
214
215 int ff_aptx_init(AVCodecContext *avctx);
216
217 #endif /* AVCODEC_APTX_H */
218