1 /*
2 * Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
3 *
4 * Use of this source code is governed by a BSD-style license
5 * that can be found in the LICENSE file in the root of the source
6 * tree. An additional intellectual property rights grant can be found
7 * in the file PATENTS. All contributing project authors may
8 * be found in the AUTHORS file in the root of the source tree.
9 */
10
11 /*
12 * The core AEC algorithm, which is presented with time-aligned signals.
13 */
14
15 #include "webrtc/modules/audio_processing/aec/aec_core.h"
16
17 #ifdef WEBRTC_AEC_DEBUG_DUMP
18 #include <stdio.h>
19 #endif
20
21 #include <assert.h>
22 #include <math.h>
23 #include <stddef.h> // size_t
24 #include <stdlib.h>
25 #include <string.h>
26
27 #include "webrtc/common_audio/ring_buffer.h"
28 #include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
29 #include "webrtc/modules/audio_processing/aec/aec_common.h"
30 #include "webrtc/modules/audio_processing/aec/aec_core_internal.h"
31 #include "webrtc/modules/audio_processing/aec/aec_rdft.h"
32 #include "webrtc/modules/audio_processing/logging/aec_logging.h"
33 #include "webrtc/modules/audio_processing/utility/delay_estimator_wrapper.h"
34 #include "webrtc/system_wrappers/include/cpu_features_wrapper.h"
35 #include "webrtc/typedefs.h"
36
37
38 // Buffer size (samples)
39 static const size_t kBufSizePartitions = 250; // 1 second of audio in 16 kHz.
40
41 // Metrics
42 static const int subCountLen = 4;
43 static const int countLen = 50;
44 static const int kDelayMetricsAggregationWindow = 1250; // 5 seconds at 16 kHz.
45
46 // Quantities to control H band scaling for SWB input
47 static const float cnScaleHband =
48 (float)0.4; // scale for comfort noise in H band
49 // Initial bin for averaging nlp gain in low band
50 static const int freqAvgIc = PART_LEN / 2;
51
52 // Matlab code to produce table:
53 // win = sqrt(hanning(63)); win = [0 ; win(1:32)];
54 // fprintf(1, '\t%.14f, %.14f, %.14f,\n', win);
55 ALIGN16_BEG const float ALIGN16_END WebRtcAec_sqrtHanning[65] = {
56 0.00000000000000f, 0.02454122852291f, 0.04906767432742f, 0.07356456359967f,
57 0.09801714032956f, 0.12241067519922f, 0.14673047445536f, 0.17096188876030f,
58 0.19509032201613f, 0.21910124015687f, 0.24298017990326f, 0.26671275747490f,
59 0.29028467725446f, 0.31368174039889f, 0.33688985339222f, 0.35989503653499f,
60 0.38268343236509f, 0.40524131400499f, 0.42755509343028f, 0.44961132965461f,
61 0.47139673682600f, 0.49289819222978f, 0.51410274419322f, 0.53499761988710f,
62 0.55557023301960f, 0.57580819141785f, 0.59569930449243f, 0.61523159058063f,
63 0.63439328416365f, 0.65317284295378f, 0.67155895484702f, 0.68954054473707f,
64 0.70710678118655f, 0.72424708295147f, 0.74095112535496f, 0.75720884650648f,
65 0.77301045336274f, 0.78834642762661f, 0.80320753148064f, 0.81758481315158f,
66 0.83146961230255f, 0.84485356524971f, 0.85772861000027f, 0.87008699110871f,
67 0.88192126434835f, 0.89322430119552f, 0.90398929312344f, 0.91420975570353f,
68 0.92387953251129f, 0.93299279883474f, 0.94154406518302f, 0.94952818059304f,
69 0.95694033573221f, 0.96377606579544f, 0.97003125319454f, 0.97570213003853f,
70 0.98078528040323f, 0.98527764238894f, 0.98917650996478f, 0.99247953459871f,
71 0.99518472667220f, 0.99729045667869f, 0.99879545620517f, 0.99969881869620f,
72 1.00000000000000f};
73
74 // Matlab code to produce table:
75 // weightCurve = [0 ; 0.3 * sqrt(linspace(0,1,64))' + 0.1];
76 // fprintf(1, '\t%.4f, %.4f, %.4f, %.4f, %.4f, %.4f,\n', weightCurve);
77 ALIGN16_BEG const float ALIGN16_END WebRtcAec_weightCurve[65] = {
78 0.0000f, 0.1000f, 0.1378f, 0.1535f, 0.1655f, 0.1756f, 0.1845f, 0.1926f,
79 0.2000f, 0.2069f, 0.2134f, 0.2195f, 0.2254f, 0.2309f, 0.2363f, 0.2414f,
80 0.2464f, 0.2512f, 0.2558f, 0.2604f, 0.2648f, 0.2690f, 0.2732f, 0.2773f,
81 0.2813f, 0.2852f, 0.2890f, 0.2927f, 0.2964f, 0.3000f, 0.3035f, 0.3070f,
82 0.3104f, 0.3138f, 0.3171f, 0.3204f, 0.3236f, 0.3268f, 0.3299f, 0.3330f,
83 0.3360f, 0.3390f, 0.3420f, 0.3449f, 0.3478f, 0.3507f, 0.3535f, 0.3563f,
84 0.3591f, 0.3619f, 0.3646f, 0.3673f, 0.3699f, 0.3726f, 0.3752f, 0.3777f,
85 0.3803f, 0.3828f, 0.3854f, 0.3878f, 0.3903f, 0.3928f, 0.3952f, 0.3976f,
86 0.4000f};
87
88 // Matlab code to produce table:
89 // overDriveCurve = [sqrt(linspace(0,1,65))' + 1];
90 // fprintf(1, '\t%.4f, %.4f, %.4f, %.4f, %.4f, %.4f,\n', overDriveCurve);
91 ALIGN16_BEG const float ALIGN16_END WebRtcAec_overDriveCurve[65] = {
92 1.0000f, 1.1250f, 1.1768f, 1.2165f, 1.2500f, 1.2795f, 1.3062f, 1.3307f,
93 1.3536f, 1.3750f, 1.3953f, 1.4146f, 1.4330f, 1.4507f, 1.4677f, 1.4841f,
94 1.5000f, 1.5154f, 1.5303f, 1.5449f, 1.5590f, 1.5728f, 1.5863f, 1.5995f,
95 1.6124f, 1.6250f, 1.6374f, 1.6495f, 1.6614f, 1.6731f, 1.6847f, 1.6960f,
96 1.7071f, 1.7181f, 1.7289f, 1.7395f, 1.7500f, 1.7603f, 1.7706f, 1.7806f,
97 1.7906f, 1.8004f, 1.8101f, 1.8197f, 1.8292f, 1.8385f, 1.8478f, 1.8570f,
98 1.8660f, 1.8750f, 1.8839f, 1.8927f, 1.9014f, 1.9100f, 1.9186f, 1.9270f,
99 1.9354f, 1.9437f, 1.9520f, 1.9601f, 1.9682f, 1.9763f, 1.9843f, 1.9922f,
100 2.0000f};
101
102 // Delay Agnostic AEC parameters, still under development and may change.
103 static const float kDelayQualityThresholdMax = 0.07f;
104 static const float kDelayQualityThresholdMin = 0.01f;
105 static const int kInitialShiftOffset = 5;
106 #if !defined(WEBRTC_ANDROID)
107 static const int kDelayCorrectionStart = 1500; // 10 ms chunks
108 #endif
109
110 // Target suppression levels for nlp modes.
111 // log{0.001, 0.00001, 0.00000001}
112 static const float kTargetSupp[3] = {-6.9f, -11.5f, -18.4f};
113
114 // Two sets of parameters, one for the extended filter mode.
115 static const float kExtendedMinOverDrive[3] = {3.0f, 6.0f, 15.0f};
116 static const float kNormalMinOverDrive[3] = {1.0f, 2.0f, 5.0f};
117 const float WebRtcAec_kExtendedSmoothingCoefficients[2][2] = {{0.9f, 0.1f},
118 {0.92f, 0.08f}};
119 const float WebRtcAec_kNormalSmoothingCoefficients[2][2] = {{0.9f, 0.1f},
120 {0.93f, 0.07f}};
121
122 // Number of partitions forming the NLP's "preferred" bands.
123 enum {
124 kPrefBandSize = 24
125 };
126
127 #ifdef WEBRTC_AEC_DEBUG_DUMP
128 extern int webrtc_aec_instance_count;
129 #endif
130
131 WebRtcAecFilterFar WebRtcAec_FilterFar;
132 WebRtcAecScaleErrorSignal WebRtcAec_ScaleErrorSignal;
133 WebRtcAecFilterAdaptation WebRtcAec_FilterAdaptation;
134 WebRtcAecOverdriveAndSuppress WebRtcAec_OverdriveAndSuppress;
135 WebRtcAecComfortNoise WebRtcAec_ComfortNoise;
136 WebRtcAecSubBandCoherence WebRtcAec_SubbandCoherence;
137 WebRtcAecStoreAsComplex WebRtcAec_StoreAsComplex;
138 WebRtcAecPartitionDelay WebRtcAec_PartitionDelay;
139 WebRtcAecWindowData WebRtcAec_WindowData;
140
MulRe(float aRe,float aIm,float bRe,float bIm)141 __inline static float MulRe(float aRe, float aIm, float bRe, float bIm) {
142 return aRe * bRe - aIm * bIm;
143 }
144
MulIm(float aRe,float aIm,float bRe,float bIm)145 __inline static float MulIm(float aRe, float aIm, float bRe, float bIm) {
146 return aRe * bIm + aIm * bRe;
147 }
148
CmpFloat(const void * a,const void * b)149 static int CmpFloat(const void* a, const void* b) {
150 const float* da = (const float*)a;
151 const float* db = (const float*)b;
152
153 return (*da > *db) - (*da < *db);
154 }
155
FilterFar(int num_partitions,int x_fft_buf_block_pos,float x_fft_buf[2][kExtendedNumPartitions * PART_LEN1],float h_fft_buf[2][kExtendedNumPartitions * PART_LEN1],float y_fft[2][PART_LEN1])156 static void FilterFar(
157 int num_partitions,
158 int x_fft_buf_block_pos,
159 float x_fft_buf[2][kExtendedNumPartitions * PART_LEN1],
160 float h_fft_buf[2][kExtendedNumPartitions * PART_LEN1],
161 float y_fft[2][PART_LEN1]) {
162 int i;
163 for (i = 0; i < num_partitions; i++) {
164 int j;
165 int xPos = (i + x_fft_buf_block_pos) * PART_LEN1;
166 int pos = i * PART_LEN1;
167 // Check for wrap
168 if (i + x_fft_buf_block_pos >= num_partitions) {
169 xPos -= num_partitions * (PART_LEN1);
170 }
171
172 for (j = 0; j < PART_LEN1; j++) {
173 y_fft[0][j] += MulRe(x_fft_buf[0][xPos + j],
174 x_fft_buf[1][xPos + j],
175 h_fft_buf[0][pos + j],
176 h_fft_buf[1][pos + j]);
177 y_fft[1][j] += MulIm(x_fft_buf[0][xPos + j],
178 x_fft_buf[1][xPos + j],
179 h_fft_buf[0][pos + j],
180 h_fft_buf[1][pos + j]);
181 }
182 }
183 }
184
ScaleErrorSignal(int extended_filter_enabled,float normal_mu,float normal_error_threshold,float x_pow[PART_LEN1],float ef[2][PART_LEN1])185 static void ScaleErrorSignal(int extended_filter_enabled,
186 float normal_mu,
187 float normal_error_threshold,
188 float x_pow[PART_LEN1],
189 float ef[2][PART_LEN1]) {
190 const float mu = extended_filter_enabled ? kExtendedMu : normal_mu;
191 const float error_threshold = extended_filter_enabled
192 ? kExtendedErrorThreshold
193 : normal_error_threshold;
194 int i;
195 float abs_ef;
196 for (i = 0; i < (PART_LEN1); i++) {
197 ef[0][i] /= (x_pow[i] + 1e-10f);
198 ef[1][i] /= (x_pow[i] + 1e-10f);
199 abs_ef = sqrtf(ef[0][i] * ef[0][i] + ef[1][i] * ef[1][i]);
200
201 if (abs_ef > error_threshold) {
202 abs_ef = error_threshold / (abs_ef + 1e-10f);
203 ef[0][i] *= abs_ef;
204 ef[1][i] *= abs_ef;
205 }
206
207 // Stepsize factor
208 ef[0][i] *= mu;
209 ef[1][i] *= mu;
210 }
211 }
212
213
FilterAdaptation(int num_partitions,int x_fft_buf_block_pos,float x_fft_buf[2][kExtendedNumPartitions * PART_LEN1],float e_fft[2][PART_LEN1],float h_fft_buf[2][kExtendedNumPartitions * PART_LEN1])214 static void FilterAdaptation(
215 int num_partitions,
216 int x_fft_buf_block_pos,
217 float x_fft_buf[2][kExtendedNumPartitions * PART_LEN1],
218 float e_fft[2][PART_LEN1],
219 float h_fft_buf[2][kExtendedNumPartitions * PART_LEN1]) {
220 int i, j;
221 float fft[PART_LEN2];
222 for (i = 0; i < num_partitions; i++) {
223 int xPos = (i + x_fft_buf_block_pos) * (PART_LEN1);
224 int pos;
225 // Check for wrap
226 if (i + x_fft_buf_block_pos >= num_partitions) {
227 xPos -= num_partitions * PART_LEN1;
228 }
229
230 pos = i * PART_LEN1;
231
232 for (j = 0; j < PART_LEN; j++) {
233
234 fft[2 * j] = MulRe(x_fft_buf[0][xPos + j],
235 -x_fft_buf[1][xPos + j],
236 e_fft[0][j],
237 e_fft[1][j]);
238 fft[2 * j + 1] = MulIm(x_fft_buf[0][xPos + j],
239 -x_fft_buf[1][xPos + j],
240 e_fft[0][j],
241 e_fft[1][j]);
242 }
243 fft[1] = MulRe(x_fft_buf[0][xPos + PART_LEN],
244 -x_fft_buf[1][xPos + PART_LEN],
245 e_fft[0][PART_LEN],
246 e_fft[1][PART_LEN]);
247
248 aec_rdft_inverse_128(fft);
249 memset(fft + PART_LEN, 0, sizeof(float) * PART_LEN);
250
251 // fft scaling
252 {
253 float scale = 2.0f / PART_LEN2;
254 for (j = 0; j < PART_LEN; j++) {
255 fft[j] *= scale;
256 }
257 }
258 aec_rdft_forward_128(fft);
259
260 h_fft_buf[0][pos] += fft[0];
261 h_fft_buf[0][pos + PART_LEN] += fft[1];
262
263 for (j = 1; j < PART_LEN; j++) {
264 h_fft_buf[0][pos + j] += fft[2 * j];
265 h_fft_buf[1][pos + j] += fft[2 * j + 1];
266 }
267 }
268 }
269
OverdriveAndSuppress(AecCore * aec,float hNl[PART_LEN1],const float hNlFb,float efw[2][PART_LEN1])270 static void OverdriveAndSuppress(AecCore* aec,
271 float hNl[PART_LEN1],
272 const float hNlFb,
273 float efw[2][PART_LEN1]) {
274 int i;
275 for (i = 0; i < PART_LEN1; i++) {
276 // Weight subbands
277 if (hNl[i] > hNlFb) {
278 hNl[i] = WebRtcAec_weightCurve[i] * hNlFb +
279 (1 - WebRtcAec_weightCurve[i]) * hNl[i];
280 }
281 hNl[i] = powf(hNl[i], aec->overDriveSm * WebRtcAec_overDriveCurve[i]);
282
283 // Suppress error signal
284 efw[0][i] *= hNl[i];
285 efw[1][i] *= hNl[i];
286
287 // Ooura fft returns incorrect sign on imaginary component. It matters here
288 // because we are making an additive change with comfort noise.
289 efw[1][i] *= -1;
290 }
291 }
292
PartitionDelay(const AecCore * aec)293 static int PartitionDelay(const AecCore* aec) {
294 // Measures the energy in each filter partition and returns the partition with
295 // highest energy.
296 // TODO(bjornv): Spread computational cost by computing one partition per
297 // block?
298 float wfEnMax = 0;
299 int i;
300 int delay = 0;
301
302 for (i = 0; i < aec->num_partitions; i++) {
303 int j;
304 int pos = i * PART_LEN1;
305 float wfEn = 0;
306 for (j = 0; j < PART_LEN1; j++) {
307 wfEn += aec->wfBuf[0][pos + j] * aec->wfBuf[0][pos + j] +
308 aec->wfBuf[1][pos + j] * aec->wfBuf[1][pos + j];
309 }
310
311 if (wfEn > wfEnMax) {
312 wfEnMax = wfEn;
313 delay = i;
314 }
315 }
316 return delay;
317 }
318
319 // Threshold to protect against the ill-effects of a zero far-end.
320 const float WebRtcAec_kMinFarendPSD = 15;
321
322 // Updates the following smoothed Power Spectral Densities (PSD):
323 // - sd : near-end
324 // - se : residual echo
325 // - sx : far-end
326 // - sde : cross-PSD of near-end and residual echo
327 // - sxd : cross-PSD of near-end and far-end
328 //
329 // In addition to updating the PSDs, also the filter diverge state is
330 // determined.
SmoothedPSD(AecCore * aec,float efw[2][PART_LEN1],float dfw[2][PART_LEN1],float xfw[2][PART_LEN1],int * extreme_filter_divergence)331 static void SmoothedPSD(AecCore* aec,
332 float efw[2][PART_LEN1],
333 float dfw[2][PART_LEN1],
334 float xfw[2][PART_LEN1],
335 int* extreme_filter_divergence) {
336 // Power estimate smoothing coefficients.
337 const float* ptrGCoh = aec->extended_filter_enabled
338 ? WebRtcAec_kExtendedSmoothingCoefficients[aec->mult - 1]
339 : WebRtcAec_kNormalSmoothingCoefficients[aec->mult - 1];
340 int i;
341 float sdSum = 0, seSum = 0;
342
343 for (i = 0; i < PART_LEN1; i++) {
344 aec->sd[i] = ptrGCoh[0] * aec->sd[i] +
345 ptrGCoh[1] * (dfw[0][i] * dfw[0][i] + dfw[1][i] * dfw[1][i]);
346 aec->se[i] = ptrGCoh[0] * aec->se[i] +
347 ptrGCoh[1] * (efw[0][i] * efw[0][i] + efw[1][i] * efw[1][i]);
348 // We threshold here to protect against the ill-effects of a zero farend.
349 // The threshold is not arbitrarily chosen, but balances protection and
350 // adverse interaction with the algorithm's tuning.
351 // TODO(bjornv): investigate further why this is so sensitive.
352 aec->sx[i] =
353 ptrGCoh[0] * aec->sx[i] +
354 ptrGCoh[1] * WEBRTC_SPL_MAX(
355 xfw[0][i] * xfw[0][i] + xfw[1][i] * xfw[1][i],
356 WebRtcAec_kMinFarendPSD);
357
358 aec->sde[i][0] =
359 ptrGCoh[0] * aec->sde[i][0] +
360 ptrGCoh[1] * (dfw[0][i] * efw[0][i] + dfw[1][i] * efw[1][i]);
361 aec->sde[i][1] =
362 ptrGCoh[0] * aec->sde[i][1] +
363 ptrGCoh[1] * (dfw[0][i] * efw[1][i] - dfw[1][i] * efw[0][i]);
364
365 aec->sxd[i][0] =
366 ptrGCoh[0] * aec->sxd[i][0] +
367 ptrGCoh[1] * (dfw[0][i] * xfw[0][i] + dfw[1][i] * xfw[1][i]);
368 aec->sxd[i][1] =
369 ptrGCoh[0] * aec->sxd[i][1] +
370 ptrGCoh[1] * (dfw[0][i] * xfw[1][i] - dfw[1][i] * xfw[0][i]);
371
372 sdSum += aec->sd[i];
373 seSum += aec->se[i];
374 }
375
376 // Divergent filter safeguard update.
377 aec->divergeState = (aec->divergeState ? 1.05f : 1.0f) * seSum > sdSum;
378
379 // Signal extreme filter divergence if the error is significantly larger
380 // than the nearend (13 dB).
381 *extreme_filter_divergence = (seSum > (19.95f * sdSum));
382 }
383
384 // Window time domain data to be used by the fft.
WindowData(float * x_windowed,const float * x)385 __inline static void WindowData(float* x_windowed, const float* x) {
386 int i;
387 for (i = 0; i < PART_LEN; i++) {
388 x_windowed[i] = x[i] * WebRtcAec_sqrtHanning[i];
389 x_windowed[PART_LEN + i] =
390 x[PART_LEN + i] * WebRtcAec_sqrtHanning[PART_LEN - i];
391 }
392 }
393
394 // Puts fft output data into a complex valued array.
StoreAsComplex(const float * data,float data_complex[2][PART_LEN1])395 __inline static void StoreAsComplex(const float* data,
396 float data_complex[2][PART_LEN1]) {
397 int i;
398 data_complex[0][0] = data[0];
399 data_complex[1][0] = 0;
400 for (i = 1; i < PART_LEN; i++) {
401 data_complex[0][i] = data[2 * i];
402 data_complex[1][i] = data[2 * i + 1];
403 }
404 data_complex[0][PART_LEN] = data[1];
405 data_complex[1][PART_LEN] = 0;
406 }
407
SubbandCoherence(AecCore * aec,float efw[2][PART_LEN1],float dfw[2][PART_LEN1],float xfw[2][PART_LEN1],float * fft,float * cohde,float * cohxd,int * extreme_filter_divergence)408 static void SubbandCoherence(AecCore* aec,
409 float efw[2][PART_LEN1],
410 float dfw[2][PART_LEN1],
411 float xfw[2][PART_LEN1],
412 float* fft,
413 float* cohde,
414 float* cohxd,
415 int* extreme_filter_divergence) {
416 int i;
417
418 SmoothedPSD(aec, efw, dfw, xfw, extreme_filter_divergence);
419
420 // Subband coherence
421 for (i = 0; i < PART_LEN1; i++) {
422 cohde[i] =
423 (aec->sde[i][0] * aec->sde[i][0] + aec->sde[i][1] * aec->sde[i][1]) /
424 (aec->sd[i] * aec->se[i] + 1e-10f);
425 cohxd[i] =
426 (aec->sxd[i][0] * aec->sxd[i][0] + aec->sxd[i][1] * aec->sxd[i][1]) /
427 (aec->sx[i] * aec->sd[i] + 1e-10f);
428 }
429 }
430
GetHighbandGain(const float * lambda,float * nlpGainHband)431 static void GetHighbandGain(const float* lambda, float* nlpGainHband) {
432 int i;
433
434 *nlpGainHband = (float)0.0;
435 for (i = freqAvgIc; i < PART_LEN1 - 1; i++) {
436 *nlpGainHband += lambda[i];
437 }
438 *nlpGainHband /= (float)(PART_LEN1 - 1 - freqAvgIc);
439 }
440
ComfortNoise(AecCore * aec,float efw[2][PART_LEN1],float comfortNoiseHband[2][PART_LEN1],const float * noisePow,const float * lambda)441 static void ComfortNoise(AecCore* aec,
442 float efw[2][PART_LEN1],
443 float comfortNoiseHband[2][PART_LEN1],
444 const float* noisePow,
445 const float* lambda) {
446 int i, num;
447 float rand[PART_LEN];
448 float noise, noiseAvg, tmp, tmpAvg;
449 int16_t randW16[PART_LEN];
450 float u[2][PART_LEN1];
451
452 const float pi2 = 6.28318530717959f;
453
454 // Generate a uniform random array on [0 1]
455 WebRtcSpl_RandUArray(randW16, PART_LEN, &aec->seed);
456 for (i = 0; i < PART_LEN; i++) {
457 rand[i] = ((float)randW16[i]) / 32768;
458 }
459
460 // Reject LF noise
461 u[0][0] = 0;
462 u[1][0] = 0;
463 for (i = 1; i < PART_LEN1; i++) {
464 tmp = pi2 * rand[i - 1];
465
466 noise = sqrtf(noisePow[i]);
467 u[0][i] = noise * cosf(tmp);
468 u[1][i] = -noise * sinf(tmp);
469 }
470 u[1][PART_LEN] = 0;
471
472 for (i = 0; i < PART_LEN1; i++) {
473 // This is the proper weighting to match the background noise power
474 tmp = sqrtf(WEBRTC_SPL_MAX(1 - lambda[i] * lambda[i], 0));
475 // tmp = 1 - lambda[i];
476 efw[0][i] += tmp * u[0][i];
477 efw[1][i] += tmp * u[1][i];
478 }
479
480 // For H band comfort noise
481 // TODO: don't compute noise and "tmp" twice. Use the previous results.
482 noiseAvg = 0.0;
483 tmpAvg = 0.0;
484 num = 0;
485 if (aec->num_bands > 1) {
486
487 // average noise scale
488 // average over second half of freq spectrum (i.e., 4->8khz)
489 // TODO: we shouldn't need num. We know how many elements we're summing.
490 for (i = PART_LEN1 >> 1; i < PART_LEN1; i++) {
491 num++;
492 noiseAvg += sqrtf(noisePow[i]);
493 }
494 noiseAvg /= (float)num;
495
496 // average nlp scale
497 // average over second half of freq spectrum (i.e., 4->8khz)
498 // TODO: we shouldn't need num. We know how many elements we're summing.
499 num = 0;
500 for (i = PART_LEN1 >> 1; i < PART_LEN1; i++) {
501 num++;
502 tmpAvg += sqrtf(WEBRTC_SPL_MAX(1 - lambda[i] * lambda[i], 0));
503 }
504 tmpAvg /= (float)num;
505
506 // Use average noise for H band
507 // TODO: we should probably have a new random vector here.
508 // Reject LF noise
509 u[0][0] = 0;
510 u[1][0] = 0;
511 for (i = 1; i < PART_LEN1; i++) {
512 tmp = pi2 * rand[i - 1];
513
514 // Use average noise for H band
515 u[0][i] = noiseAvg * (float)cos(tmp);
516 u[1][i] = -noiseAvg * (float)sin(tmp);
517 }
518 u[1][PART_LEN] = 0;
519
520 for (i = 0; i < PART_LEN1; i++) {
521 // Use average NLP weight for H band
522 comfortNoiseHband[0][i] = tmpAvg * u[0][i];
523 comfortNoiseHband[1][i] = tmpAvg * u[1][i];
524 }
525 } else {
526 memset(comfortNoiseHband, 0,
527 2 * PART_LEN1 * sizeof(comfortNoiseHband[0][0]));
528 }
529 }
530
InitLevel(PowerLevel * level)531 static void InitLevel(PowerLevel* level) {
532 const float kBigFloat = 1E17f;
533
534 level->averagelevel = 0;
535 level->framelevel = 0;
536 level->minlevel = kBigFloat;
537 level->frsum = 0;
538 level->sfrsum = 0;
539 level->frcounter = 0;
540 level->sfrcounter = 0;
541 }
542
InitStats(Stats * stats)543 static void InitStats(Stats* stats) {
544 stats->instant = kOffsetLevel;
545 stats->average = kOffsetLevel;
546 stats->max = kOffsetLevel;
547 stats->min = kOffsetLevel * (-1);
548 stats->sum = 0;
549 stats->hisum = 0;
550 stats->himean = kOffsetLevel;
551 stats->counter = 0;
552 stats->hicounter = 0;
553 }
554
InitMetrics(AecCore * self)555 static void InitMetrics(AecCore* self) {
556 self->stateCounter = 0;
557 InitLevel(&self->farlevel);
558 InitLevel(&self->nearlevel);
559 InitLevel(&self->linoutlevel);
560 InitLevel(&self->nlpoutlevel);
561
562 InitStats(&self->erl);
563 InitStats(&self->erle);
564 InitStats(&self->aNlp);
565 InitStats(&self->rerl);
566 }
567
UpdateLevel(PowerLevel * level,float in[2][PART_LEN1])568 static void UpdateLevel(PowerLevel* level, float in[2][PART_LEN1]) {
569 // Do the energy calculation in the frequency domain. The FFT is performed on
570 // a segment of PART_LEN2 samples due to overlap, but we only want the energy
571 // of half that data (the last PART_LEN samples). Parseval's relation states
572 // that the energy is preserved according to
573 //
574 // \sum_{n=0}^{N-1} |x(n)|^2 = 1/N * \sum_{n=0}^{N-1} |X(n)|^2
575 // = ENERGY,
576 //
577 // where N = PART_LEN2. Since we are only interested in calculating the energy
578 // for the last PART_LEN samples we approximate by calculating ENERGY and
579 // divide by 2,
580 //
581 // \sum_{n=N/2}^{N-1} |x(n)|^2 ~= ENERGY / 2
582 //
583 // Since we deal with real valued time domain signals we only store frequency
584 // bins [0, PART_LEN], which is what |in| consists of. To calculate ENERGY we
585 // need to add the contribution from the missing part in
586 // [PART_LEN+1, PART_LEN2-1]. These values are, up to a phase shift, identical
587 // with the values in [1, PART_LEN-1], hence multiply those values by 2. This
588 // is the values in the for loop below, but multiplication by 2 and division
589 // by 2 cancel.
590
591 // TODO(bjornv): Investigate reusing energy calculations performed at other
592 // places in the code.
593 int k = 1;
594 // Imaginary parts are zero at end points and left out of the calculation.
595 float energy = (in[0][0] * in[0][0]) / 2;
596 energy += (in[0][PART_LEN] * in[0][PART_LEN]) / 2;
597
598 for (k = 1; k < PART_LEN; k++) {
599 energy += (in[0][k] * in[0][k] + in[1][k] * in[1][k]);
600 }
601 energy /= PART_LEN2;
602
603 level->sfrsum += energy;
604 level->sfrcounter++;
605
606 if (level->sfrcounter > subCountLen) {
607 level->framelevel = level->sfrsum / (subCountLen * PART_LEN);
608 level->sfrsum = 0;
609 level->sfrcounter = 0;
610 if (level->framelevel > 0) {
611 if (level->framelevel < level->minlevel) {
612 level->minlevel = level->framelevel; // New minimum.
613 } else {
614 level->minlevel *= (1 + 0.001f); // Small increase.
615 }
616 }
617 level->frcounter++;
618 level->frsum += level->framelevel;
619 if (level->frcounter > countLen) {
620 level->averagelevel = level->frsum / countLen;
621 level->frsum = 0;
622 level->frcounter = 0;
623 }
624 }
625 }
626
UpdateMetrics(AecCore * aec)627 static void UpdateMetrics(AecCore* aec) {
628 float dtmp, dtmp2;
629
630 const float actThresholdNoisy = 8.0f;
631 const float actThresholdClean = 40.0f;
632 const float safety = 0.99995f;
633 const float noisyPower = 300000.0f;
634
635 float actThreshold;
636 float echo, suppressedEcho;
637
638 if (aec->echoState) { // Check if echo is likely present
639 aec->stateCounter++;
640 }
641
642 if (aec->farlevel.frcounter == 0) {
643
644 if (aec->farlevel.minlevel < noisyPower) {
645 actThreshold = actThresholdClean;
646 } else {
647 actThreshold = actThresholdNoisy;
648 }
649
650 if ((aec->stateCounter > (0.5f * countLen * subCountLen)) &&
651 (aec->farlevel.sfrcounter == 0)
652
653 // Estimate in active far-end segments only
654 &&
655 (aec->farlevel.averagelevel >
656 (actThreshold * aec->farlevel.minlevel))) {
657
658 // Subtract noise power
659 echo = aec->nearlevel.averagelevel - safety * aec->nearlevel.minlevel;
660
661 // ERL
662 dtmp = 10 * (float)log10(aec->farlevel.averagelevel /
663 aec->nearlevel.averagelevel +
664 1e-10f);
665 dtmp2 = 10 * (float)log10(aec->farlevel.averagelevel / echo + 1e-10f);
666
667 aec->erl.instant = dtmp;
668 if (dtmp > aec->erl.max) {
669 aec->erl.max = dtmp;
670 }
671
672 if (dtmp < aec->erl.min) {
673 aec->erl.min = dtmp;
674 }
675
676 aec->erl.counter++;
677 aec->erl.sum += dtmp;
678 aec->erl.average = aec->erl.sum / aec->erl.counter;
679
680 // Upper mean
681 if (dtmp > aec->erl.average) {
682 aec->erl.hicounter++;
683 aec->erl.hisum += dtmp;
684 aec->erl.himean = aec->erl.hisum / aec->erl.hicounter;
685 }
686
687 // A_NLP
688 dtmp = 10 * (float)log10(aec->nearlevel.averagelevel /
689 (2 * aec->linoutlevel.averagelevel) +
690 1e-10f);
691
692 // subtract noise power
693 suppressedEcho = 2 * (aec->linoutlevel.averagelevel -
694 safety * aec->linoutlevel.minlevel);
695
696 dtmp2 = 10 * (float)log10(echo / suppressedEcho + 1e-10f);
697
698 aec->aNlp.instant = dtmp2;
699 if (dtmp > aec->aNlp.max) {
700 aec->aNlp.max = dtmp;
701 }
702
703 if (dtmp < aec->aNlp.min) {
704 aec->aNlp.min = dtmp;
705 }
706
707 aec->aNlp.counter++;
708 aec->aNlp.sum += dtmp;
709 aec->aNlp.average = aec->aNlp.sum / aec->aNlp.counter;
710
711 // Upper mean
712 if (dtmp > aec->aNlp.average) {
713 aec->aNlp.hicounter++;
714 aec->aNlp.hisum += dtmp;
715 aec->aNlp.himean = aec->aNlp.hisum / aec->aNlp.hicounter;
716 }
717
718 // ERLE
719
720 // subtract noise power
721 suppressedEcho = 2 * (aec->nlpoutlevel.averagelevel -
722 safety * aec->nlpoutlevel.minlevel);
723
724 dtmp = 10 * (float)log10(aec->nearlevel.averagelevel /
725 (2 * aec->nlpoutlevel.averagelevel) +
726 1e-10f);
727 dtmp2 = 10 * (float)log10(echo / suppressedEcho + 1e-10f);
728
729 dtmp = dtmp2;
730 aec->erle.instant = dtmp;
731 if (dtmp > aec->erle.max) {
732 aec->erle.max = dtmp;
733 }
734
735 if (dtmp < aec->erle.min) {
736 aec->erle.min = dtmp;
737 }
738
739 aec->erle.counter++;
740 aec->erle.sum += dtmp;
741 aec->erle.average = aec->erle.sum / aec->erle.counter;
742
743 // Upper mean
744 if (dtmp > aec->erle.average) {
745 aec->erle.hicounter++;
746 aec->erle.hisum += dtmp;
747 aec->erle.himean = aec->erle.hisum / aec->erle.hicounter;
748 }
749 }
750
751 aec->stateCounter = 0;
752 }
753 }
754
UpdateDelayMetrics(AecCore * self)755 static void UpdateDelayMetrics(AecCore* self) {
756 int i = 0;
757 int delay_values = 0;
758 int median = 0;
759 int lookahead = WebRtc_lookahead(self->delay_estimator);
760 const int kMsPerBlock = PART_LEN / (self->mult * 8);
761 int64_t l1_norm = 0;
762
763 if (self->num_delay_values == 0) {
764 // We have no new delay value data. Even though -1 is a valid |median| in
765 // the sense that we allow negative values, it will practically never be
766 // used since multiples of |kMsPerBlock| will always be returned.
767 // We therefore use -1 to indicate in the logs that the delay estimator was
768 // not able to estimate the delay.
769 self->delay_median = -1;
770 self->delay_std = -1;
771 self->fraction_poor_delays = -1;
772 return;
773 }
774
775 // Start value for median count down.
776 delay_values = self->num_delay_values >> 1;
777 // Get median of delay values since last update.
778 for (i = 0; i < kHistorySizeBlocks; i++) {
779 delay_values -= self->delay_histogram[i];
780 if (delay_values < 0) {
781 median = i;
782 break;
783 }
784 }
785 // Account for lookahead.
786 self->delay_median = (median - lookahead) * kMsPerBlock;
787
788 // Calculate the L1 norm, with median value as central moment.
789 for (i = 0; i < kHistorySizeBlocks; i++) {
790 l1_norm += abs(i - median) * self->delay_histogram[i];
791 }
792 self->delay_std = (int)((l1_norm + self->num_delay_values / 2) /
793 self->num_delay_values) * kMsPerBlock;
794
795 // Determine fraction of delays that are out of bounds, that is, either
796 // negative (anti-causal system) or larger than the AEC filter length.
797 {
798 int num_delays_out_of_bounds = self->num_delay_values;
799 const int histogram_length = sizeof(self->delay_histogram) /
800 sizeof(self->delay_histogram[0]);
801 for (i = lookahead; i < lookahead + self->num_partitions; ++i) {
802 if (i < histogram_length)
803 num_delays_out_of_bounds -= self->delay_histogram[i];
804 }
805 self->fraction_poor_delays = (float)num_delays_out_of_bounds /
806 self->num_delay_values;
807 }
808
809 // Reset histogram.
810 memset(self->delay_histogram, 0, sizeof(self->delay_histogram));
811 self->num_delay_values = 0;
812
813 return;
814 }
815
ScaledInverseFft(float freq_data[2][PART_LEN1],float time_data[PART_LEN2],float scale,int conjugate)816 static void ScaledInverseFft(float freq_data[2][PART_LEN1],
817 float time_data[PART_LEN2],
818 float scale,
819 int conjugate) {
820 int i;
821 const float normalization = scale / ((float)PART_LEN2);
822 const float sign = (conjugate ? -1 : 1);
823 time_data[0] = freq_data[0][0] * normalization;
824 time_data[1] = freq_data[0][PART_LEN] * normalization;
825 for (i = 1; i < PART_LEN; i++) {
826 time_data[2 * i] = freq_data[0][i] * normalization;
827 time_data[2 * i + 1] = sign * freq_data[1][i] * normalization;
828 }
829 aec_rdft_inverse_128(time_data);
830 }
831
832
Fft(float time_data[PART_LEN2],float freq_data[2][PART_LEN1])833 static void Fft(float time_data[PART_LEN2],
834 float freq_data[2][PART_LEN1]) {
835 int i;
836 aec_rdft_forward_128(time_data);
837
838 // Reorder fft output data.
839 freq_data[1][0] = 0;
840 freq_data[1][PART_LEN] = 0;
841 freq_data[0][0] = time_data[0];
842 freq_data[0][PART_LEN] = time_data[1];
843 for (i = 1; i < PART_LEN; i++) {
844 freq_data[0][i] = time_data[2 * i];
845 freq_data[1][i] = time_data[2 * i + 1];
846 }
847 }
848
849
SignalBasedDelayCorrection(AecCore * self)850 static int SignalBasedDelayCorrection(AecCore* self) {
851 int delay_correction = 0;
852 int last_delay = -2;
853 assert(self != NULL);
854 #if !defined(WEBRTC_ANDROID)
855 // On desktops, turn on correction after |kDelayCorrectionStart| frames. This
856 // is to let the delay estimation get a chance to converge. Also, if the
857 // playout audio volume is low (or even muted) the delay estimation can return
858 // a very large delay, which will break the AEC if it is applied.
859 if (self->frame_count < kDelayCorrectionStart) {
860 return 0;
861 }
862 #endif
863
864 // 1. Check for non-negative delay estimate. Note that the estimates we get
865 // from the delay estimation are not compensated for lookahead. Hence, a
866 // negative |last_delay| is an invalid one.
867 // 2. Verify that there is a delay change. In addition, only allow a change
868 // if the delay is outside a certain region taking the AEC filter length
869 // into account.
870 // TODO(bjornv): Investigate if we can remove the non-zero delay change check.
871 // 3. Only allow delay correction if the delay estimation quality exceeds
872 // |delay_quality_threshold|.
873 // 4. Finally, verify that the proposed |delay_correction| is feasible by
874 // comparing with the size of the far-end buffer.
875 last_delay = WebRtc_last_delay(self->delay_estimator);
876 if ((last_delay >= 0) &&
877 (last_delay != self->previous_delay) &&
878 (WebRtc_last_delay_quality(self->delay_estimator) >
879 self->delay_quality_threshold)) {
880 int delay = last_delay - WebRtc_lookahead(self->delay_estimator);
881 // Allow for a slack in the actual delay, defined by a |lower_bound| and an
882 // |upper_bound|. The adaptive echo cancellation filter is currently
883 // |num_partitions| (of 64 samples) long. If the delay estimate is negative
884 // or at least 3/4 of the filter length we open up for correction.
885 const int lower_bound = 0;
886 const int upper_bound = self->num_partitions * 3 / 4;
887 const int do_correction = delay <= lower_bound || delay > upper_bound;
888 if (do_correction == 1) {
889 int available_read = (int)WebRtc_available_read(self->far_time_buf);
890 // With |shift_offset| we gradually rely on the delay estimates. For
891 // positive delays we reduce the correction by |shift_offset| to lower the
892 // risk of pushing the AEC into a non causal state. For negative delays
893 // we rely on the values up to a rounding error, hence compensate by 1
894 // element to make sure to push the delay into the causal region.
895 delay_correction = -delay;
896 delay_correction += delay > self->shift_offset ? self->shift_offset : 1;
897 self->shift_offset--;
898 self->shift_offset = (self->shift_offset <= 1 ? 1 : self->shift_offset);
899 if (delay_correction > available_read - self->mult - 1) {
900 // There is not enough data in the buffer to perform this shift. Hence,
901 // we do not rely on the delay estimate and do nothing.
902 delay_correction = 0;
903 } else {
904 self->previous_delay = last_delay;
905 ++self->delay_correction_count;
906 }
907 }
908 }
909 // Update the |delay_quality_threshold| once we have our first delay
910 // correction.
911 if (self->delay_correction_count > 0) {
912 float delay_quality = WebRtc_last_delay_quality(self->delay_estimator);
913 delay_quality = (delay_quality > kDelayQualityThresholdMax ?
914 kDelayQualityThresholdMax : delay_quality);
915 self->delay_quality_threshold =
916 (delay_quality > self->delay_quality_threshold ? delay_quality :
917 self->delay_quality_threshold);
918 }
919 return delay_correction;
920 }
921
EchoSubtraction(AecCore * aec,int num_partitions,int x_fft_buf_block_pos,int metrics_mode,int extended_filter_enabled,float normal_mu,float normal_error_threshold,float x_fft_buf[2][kExtendedNumPartitions * PART_LEN1],float * const y,float x_pow[PART_LEN1],float h_fft_buf[2][kExtendedNumPartitions * PART_LEN1],PowerLevel * linout_level,float echo_subtractor_output[PART_LEN])922 static void EchoSubtraction(
923 AecCore* aec,
924 int num_partitions,
925 int x_fft_buf_block_pos,
926 int metrics_mode,
927 int extended_filter_enabled,
928 float normal_mu,
929 float normal_error_threshold,
930 float x_fft_buf[2][kExtendedNumPartitions * PART_LEN1],
931 float* const y,
932 float x_pow[PART_LEN1],
933 float h_fft_buf[2][kExtendedNumPartitions * PART_LEN1],
934 PowerLevel* linout_level,
935 float echo_subtractor_output[PART_LEN]) {
936 float s_fft[2][PART_LEN1];
937 float e_extended[PART_LEN2];
938 float s_extended[PART_LEN2];
939 float *s;
940 float e[PART_LEN];
941 float e_fft[2][PART_LEN1];
942 int i;
943 memset(s_fft, 0, sizeof(s_fft));
944
945 // Conditionally reset the echo subtraction filter if the filter has diverged
946 // significantly.
947 if (!aec->extended_filter_enabled &&
948 aec->extreme_filter_divergence) {
949 memset(aec->wfBuf, 0, sizeof(aec->wfBuf));
950 aec->extreme_filter_divergence = 0;
951 }
952
953 // Produce echo estimate s_fft.
954 WebRtcAec_FilterFar(num_partitions,
955 x_fft_buf_block_pos,
956 x_fft_buf,
957 h_fft_buf,
958 s_fft);
959
960 // Compute the time-domain echo estimate s.
961 ScaledInverseFft(s_fft, s_extended, 2.0f, 0);
962 s = &s_extended[PART_LEN];
963
964 // Compute the time-domain echo prediction error.
965 for (i = 0; i < PART_LEN; ++i) {
966 e[i] = y[i] - s[i];
967 }
968
969 // Compute the frequency domain echo prediction error.
970 memset(e_extended, 0, sizeof(float) * PART_LEN);
971 memcpy(e_extended + PART_LEN, e, sizeof(float) * PART_LEN);
972 Fft(e_extended, e_fft);
973
974 RTC_AEC_DEBUG_RAW_WRITE(aec->e_fft_file,
975 &e_fft[0][0],
976 sizeof(e_fft[0][0]) * PART_LEN1 * 2);
977
978 if (metrics_mode == 1) {
979 // Note that the first PART_LEN samples in fft (before transformation) are
980 // zero. Hence, the scaling by two in UpdateLevel() should not be
981 // performed. That scaling is taken care of in UpdateMetrics() instead.
982 UpdateLevel(linout_level, e_fft);
983 }
984
985 // Scale error signal inversely with far power.
986 WebRtcAec_ScaleErrorSignal(extended_filter_enabled,
987 normal_mu,
988 normal_error_threshold,
989 x_pow,
990 e_fft);
991 WebRtcAec_FilterAdaptation(num_partitions,
992 x_fft_buf_block_pos,
993 x_fft_buf,
994 e_fft,
995 h_fft_buf);
996 memcpy(echo_subtractor_output, e, sizeof(float) * PART_LEN);
997 }
998
999
EchoSuppression(AecCore * aec,float farend[PART_LEN2],float * echo_subtractor_output,float * output,float * const * outputH)1000 static void EchoSuppression(AecCore* aec,
1001 float farend[PART_LEN2],
1002 float* echo_subtractor_output,
1003 float* output,
1004 float* const* outputH) {
1005 float efw[2][PART_LEN1];
1006 float xfw[2][PART_LEN1];
1007 float dfw[2][PART_LEN1];
1008 float comfortNoiseHband[2][PART_LEN1];
1009 float fft[PART_LEN2];
1010 float nlpGainHband;
1011 int i;
1012 size_t j;
1013
1014 // Coherence and non-linear filter
1015 float cohde[PART_LEN1], cohxd[PART_LEN1];
1016 float hNlDeAvg, hNlXdAvg;
1017 float hNl[PART_LEN1];
1018 float hNlPref[kPrefBandSize];
1019 float hNlFb = 0, hNlFbLow = 0;
1020 const float prefBandQuant = 0.75f, prefBandQuantLow = 0.5f;
1021 const int prefBandSize = kPrefBandSize / aec->mult;
1022 const int minPrefBand = 4 / aec->mult;
1023 // Power estimate smoothing coefficients.
1024 const float* min_overdrive = aec->extended_filter_enabled
1025 ? kExtendedMinOverDrive
1026 : kNormalMinOverDrive;
1027
1028 // Filter energy
1029 const int delayEstInterval = 10 * aec->mult;
1030
1031 float* xfw_ptr = NULL;
1032
1033 // Update eBuf with echo subtractor output.
1034 memcpy(aec->eBuf + PART_LEN,
1035 echo_subtractor_output,
1036 sizeof(float) * PART_LEN);
1037
1038 // Analysis filter banks for the echo suppressor.
1039 // Windowed near-end ffts.
1040 WindowData(fft, aec->dBuf);
1041 aec_rdft_forward_128(fft);
1042 StoreAsComplex(fft, dfw);
1043
1044 // Windowed echo suppressor output ffts.
1045 WindowData(fft, aec->eBuf);
1046 aec_rdft_forward_128(fft);
1047 StoreAsComplex(fft, efw);
1048
1049 // NLP
1050
1051 // Convert far-end partition to the frequency domain with windowing.
1052 WindowData(fft, farend);
1053 Fft(fft, xfw);
1054 xfw_ptr = &xfw[0][0];
1055
1056 // Buffer far.
1057 memcpy(aec->xfwBuf, xfw_ptr, sizeof(float) * 2 * PART_LEN1);
1058
1059 aec->delayEstCtr++;
1060 if (aec->delayEstCtr == delayEstInterval) {
1061 aec->delayEstCtr = 0;
1062 aec->delayIdx = WebRtcAec_PartitionDelay(aec);
1063 }
1064
1065 // Use delayed far.
1066 memcpy(xfw,
1067 aec->xfwBuf + aec->delayIdx * PART_LEN1,
1068 sizeof(xfw[0][0]) * 2 * PART_LEN1);
1069
1070 WebRtcAec_SubbandCoherence(aec, efw, dfw, xfw, fft, cohde, cohxd,
1071 &aec->extreme_filter_divergence);
1072
1073 // Select the microphone signal as output if the filter is deemed to have
1074 // diverged.
1075 if (aec->divergeState) {
1076 memcpy(efw, dfw, sizeof(efw[0][0]) * 2 * PART_LEN1);
1077 }
1078
1079 hNlXdAvg = 0;
1080 for (i = minPrefBand; i < prefBandSize + minPrefBand; i++) {
1081 hNlXdAvg += cohxd[i];
1082 }
1083 hNlXdAvg /= prefBandSize;
1084 hNlXdAvg = 1 - hNlXdAvg;
1085
1086 hNlDeAvg = 0;
1087 for (i = minPrefBand; i < prefBandSize + minPrefBand; i++) {
1088 hNlDeAvg += cohde[i];
1089 }
1090 hNlDeAvg /= prefBandSize;
1091
1092 if (hNlXdAvg < 0.75f && hNlXdAvg < aec->hNlXdAvgMin) {
1093 aec->hNlXdAvgMin = hNlXdAvg;
1094 }
1095
1096 if (hNlDeAvg > 0.98f && hNlXdAvg > 0.9f) {
1097 aec->stNearState = 1;
1098 } else if (hNlDeAvg < 0.95f || hNlXdAvg < 0.8f) {
1099 aec->stNearState = 0;
1100 }
1101
1102 if (aec->hNlXdAvgMin == 1) {
1103 aec->echoState = 0;
1104 aec->overDrive = min_overdrive[aec->nlp_mode];
1105
1106 if (aec->stNearState == 1) {
1107 memcpy(hNl, cohde, sizeof(hNl));
1108 hNlFb = hNlDeAvg;
1109 hNlFbLow = hNlDeAvg;
1110 } else {
1111 for (i = 0; i < PART_LEN1; i++) {
1112 hNl[i] = 1 - cohxd[i];
1113 }
1114 hNlFb = hNlXdAvg;
1115 hNlFbLow = hNlXdAvg;
1116 }
1117 } else {
1118
1119 if (aec->stNearState == 1) {
1120 aec->echoState = 0;
1121 memcpy(hNl, cohde, sizeof(hNl));
1122 hNlFb = hNlDeAvg;
1123 hNlFbLow = hNlDeAvg;
1124 } else {
1125 aec->echoState = 1;
1126 for (i = 0; i < PART_LEN1; i++) {
1127 hNl[i] = WEBRTC_SPL_MIN(cohde[i], 1 - cohxd[i]);
1128 }
1129
1130 // Select an order statistic from the preferred bands.
1131 // TODO: Using quicksort now, but a selection algorithm may be preferred.
1132 memcpy(hNlPref, &hNl[minPrefBand], sizeof(float) * prefBandSize);
1133 qsort(hNlPref, prefBandSize, sizeof(float), CmpFloat);
1134 hNlFb = hNlPref[(int)floor(prefBandQuant * (prefBandSize - 1))];
1135 hNlFbLow = hNlPref[(int)floor(prefBandQuantLow * (prefBandSize - 1))];
1136 }
1137 }
1138
1139 // Track the local filter minimum to determine suppression overdrive.
1140 if (hNlFbLow < 0.6f && hNlFbLow < aec->hNlFbLocalMin) {
1141 aec->hNlFbLocalMin = hNlFbLow;
1142 aec->hNlFbMin = hNlFbLow;
1143 aec->hNlNewMin = 1;
1144 aec->hNlMinCtr = 0;
1145 }
1146 aec->hNlFbLocalMin =
1147 WEBRTC_SPL_MIN(aec->hNlFbLocalMin + 0.0008f / aec->mult, 1);
1148 aec->hNlXdAvgMin = WEBRTC_SPL_MIN(aec->hNlXdAvgMin + 0.0006f / aec->mult, 1);
1149
1150 if (aec->hNlNewMin == 1) {
1151 aec->hNlMinCtr++;
1152 }
1153 if (aec->hNlMinCtr == 2) {
1154 aec->hNlNewMin = 0;
1155 aec->hNlMinCtr = 0;
1156 aec->overDrive =
1157 WEBRTC_SPL_MAX(kTargetSupp[aec->nlp_mode] /
1158 ((float)log(aec->hNlFbMin + 1e-10f) + 1e-10f),
1159 min_overdrive[aec->nlp_mode]);
1160 }
1161
1162 // Smooth the overdrive.
1163 if (aec->overDrive < aec->overDriveSm) {
1164 aec->overDriveSm = 0.99f * aec->overDriveSm + 0.01f * aec->overDrive;
1165 } else {
1166 aec->overDriveSm = 0.9f * aec->overDriveSm + 0.1f * aec->overDrive;
1167 }
1168
1169 WebRtcAec_OverdriveAndSuppress(aec, hNl, hNlFb, efw);
1170
1171 // Add comfort noise.
1172 WebRtcAec_ComfortNoise(aec, efw, comfortNoiseHband, aec->noisePow, hNl);
1173
1174 // TODO(bjornv): Investigate how to take the windowing below into account if
1175 // needed.
1176 if (aec->metricsMode == 1) {
1177 // Note that we have a scaling by two in the time domain |eBuf|.
1178 // In addition the time domain signal is windowed before transformation,
1179 // losing half the energy on the average. We take care of the first
1180 // scaling only in UpdateMetrics().
1181 UpdateLevel(&aec->nlpoutlevel, efw);
1182 }
1183
1184 // Inverse error fft.
1185 ScaledInverseFft(efw, fft, 2.0f, 1);
1186
1187 // Overlap and add to obtain output.
1188 for (i = 0; i < PART_LEN; i++) {
1189 output[i] = (fft[i] * WebRtcAec_sqrtHanning[i] +
1190 aec->outBuf[i] * WebRtcAec_sqrtHanning[PART_LEN - i]);
1191
1192 // Saturate output to keep it in the allowed range.
1193 output[i] = WEBRTC_SPL_SAT(
1194 WEBRTC_SPL_WORD16_MAX, output[i], WEBRTC_SPL_WORD16_MIN);
1195 }
1196 memcpy(aec->outBuf, &fft[PART_LEN], PART_LEN * sizeof(aec->outBuf[0]));
1197
1198 // For H band
1199 if (aec->num_bands > 1) {
1200 // H band gain
1201 // average nlp over low band: average over second half of freq spectrum
1202 // (4->8khz)
1203 GetHighbandGain(hNl, &nlpGainHband);
1204
1205 // Inverse comfort_noise
1206 ScaledInverseFft(comfortNoiseHband, fft, 2.0f, 0);
1207
1208 // compute gain factor
1209 for (j = 0; j < aec->num_bands - 1; ++j) {
1210 for (i = 0; i < PART_LEN; i++) {
1211 outputH[j][i] = aec->dBufH[j][i] * nlpGainHband;
1212 }
1213 }
1214
1215 // Add some comfort noise where Hband is attenuated.
1216 for (i = 0; i < PART_LEN; i++) {
1217 outputH[0][i] += cnScaleHband * fft[i];
1218 }
1219
1220 // Saturate output to keep it in the allowed range.
1221 for (j = 0; j < aec->num_bands - 1; ++j) {
1222 for (i = 0; i < PART_LEN; i++) {
1223 outputH[j][i] = WEBRTC_SPL_SAT(
1224 WEBRTC_SPL_WORD16_MAX, outputH[j][i], WEBRTC_SPL_WORD16_MIN);
1225 }
1226 }
1227
1228 }
1229
1230 // Copy the current block to the old position.
1231 memcpy(aec->dBuf, aec->dBuf + PART_LEN, sizeof(float) * PART_LEN);
1232 memcpy(aec->eBuf, aec->eBuf + PART_LEN, sizeof(float) * PART_LEN);
1233
1234 // Copy the current block to the old position for H band
1235 for (j = 0; j < aec->num_bands - 1; ++j) {
1236 memcpy(aec->dBufH[j], aec->dBufH[j] + PART_LEN, sizeof(float) * PART_LEN);
1237 }
1238
1239 memmove(aec->xfwBuf + PART_LEN1,
1240 aec->xfwBuf,
1241 sizeof(aec->xfwBuf) - sizeof(complex_t) * PART_LEN1);
1242 }
1243
ProcessBlock(AecCore * aec)1244 static void ProcessBlock(AecCore* aec) {
1245 size_t i;
1246
1247 float fft[PART_LEN2];
1248 float xf[2][PART_LEN1];
1249 float df[2][PART_LEN1];
1250 float far_spectrum = 0.0f;
1251 float near_spectrum = 0.0f;
1252 float abs_far_spectrum[PART_LEN1];
1253 float abs_near_spectrum[PART_LEN1];
1254
1255 const float gPow[2] = {0.9f, 0.1f};
1256
1257 // Noise estimate constants.
1258 const int noiseInitBlocks = 500 * aec->mult;
1259 const float step = 0.1f;
1260 const float ramp = 1.0002f;
1261 const float gInitNoise[2] = {0.999f, 0.001f};
1262
1263 float nearend[PART_LEN];
1264 float* nearend_ptr = NULL;
1265 float farend[PART_LEN2];
1266 float* farend_ptr = NULL;
1267 float echo_subtractor_output[PART_LEN];
1268 float output[PART_LEN];
1269 float outputH[NUM_HIGH_BANDS_MAX][PART_LEN];
1270 float* outputH_ptr[NUM_HIGH_BANDS_MAX];
1271 float* xf_ptr = NULL;
1272
1273 for (i = 0; i < NUM_HIGH_BANDS_MAX; ++i) {
1274 outputH_ptr[i] = outputH[i];
1275 }
1276
1277 // Concatenate old and new nearend blocks.
1278 for (i = 0; i < aec->num_bands - 1; ++i) {
1279 WebRtc_ReadBuffer(aec->nearFrBufH[i],
1280 (void**)&nearend_ptr,
1281 nearend,
1282 PART_LEN);
1283 memcpy(aec->dBufH[i] + PART_LEN, nearend_ptr, sizeof(nearend));
1284 }
1285 WebRtc_ReadBuffer(aec->nearFrBuf, (void**)&nearend_ptr, nearend, PART_LEN);
1286 memcpy(aec->dBuf + PART_LEN, nearend_ptr, sizeof(nearend));
1287
1288 // We should always have at least one element stored in |far_buf|.
1289 assert(WebRtc_available_read(aec->far_time_buf) > 0);
1290 WebRtc_ReadBuffer(aec->far_time_buf, (void**)&farend_ptr, farend, 1);
1291
1292 #ifdef WEBRTC_AEC_DEBUG_DUMP
1293 {
1294 // TODO(minyue): |farend_ptr| starts from buffered samples. This will be
1295 // modified when |aec->far_time_buf| is revised.
1296 RTC_AEC_DEBUG_WAV_WRITE(aec->farFile, &farend_ptr[PART_LEN], PART_LEN);
1297
1298 RTC_AEC_DEBUG_WAV_WRITE(aec->nearFile, nearend_ptr, PART_LEN);
1299 }
1300 #endif
1301
1302 // Convert far-end signal to the frequency domain.
1303 memcpy(fft, farend_ptr, sizeof(float) * PART_LEN2);
1304 Fft(fft, xf);
1305 xf_ptr = &xf[0][0];
1306
1307 // Near fft
1308 memcpy(fft, aec->dBuf, sizeof(float) * PART_LEN2);
1309 Fft(fft, df);
1310
1311 // Power smoothing
1312 for (i = 0; i < PART_LEN1; i++) {
1313 far_spectrum = (xf_ptr[i] * xf_ptr[i]) +
1314 (xf_ptr[PART_LEN1 + i] * xf_ptr[PART_LEN1 + i]);
1315 aec->xPow[i] =
1316 gPow[0] * aec->xPow[i] + gPow[1] * aec->num_partitions * far_spectrum;
1317 // Calculate absolute spectra
1318 abs_far_spectrum[i] = sqrtf(far_spectrum);
1319
1320 near_spectrum = df[0][i] * df[0][i] + df[1][i] * df[1][i];
1321 aec->dPow[i] = gPow[0] * aec->dPow[i] + gPow[1] * near_spectrum;
1322 // Calculate absolute spectra
1323 abs_near_spectrum[i] = sqrtf(near_spectrum);
1324 }
1325
1326 // Estimate noise power. Wait until dPow is more stable.
1327 if (aec->noiseEstCtr > 50) {
1328 for (i = 0; i < PART_LEN1; i++) {
1329 if (aec->dPow[i] < aec->dMinPow[i]) {
1330 aec->dMinPow[i] =
1331 (aec->dPow[i] + step * (aec->dMinPow[i] - aec->dPow[i])) * ramp;
1332 } else {
1333 aec->dMinPow[i] *= ramp;
1334 }
1335 }
1336 }
1337
1338 // Smooth increasing noise power from zero at the start,
1339 // to avoid a sudden burst of comfort noise.
1340 if (aec->noiseEstCtr < noiseInitBlocks) {
1341 aec->noiseEstCtr++;
1342 for (i = 0; i < PART_LEN1; i++) {
1343 if (aec->dMinPow[i] > aec->dInitMinPow[i]) {
1344 aec->dInitMinPow[i] = gInitNoise[0] * aec->dInitMinPow[i] +
1345 gInitNoise[1] * aec->dMinPow[i];
1346 } else {
1347 aec->dInitMinPow[i] = aec->dMinPow[i];
1348 }
1349 }
1350 aec->noisePow = aec->dInitMinPow;
1351 } else {
1352 aec->noisePow = aec->dMinPow;
1353 }
1354
1355 // Block wise delay estimation used for logging
1356 if (aec->delay_logging_enabled) {
1357 if (WebRtc_AddFarSpectrumFloat(
1358 aec->delay_estimator_farend, abs_far_spectrum, PART_LEN1) == 0) {
1359 int delay_estimate = WebRtc_DelayEstimatorProcessFloat(
1360 aec->delay_estimator, abs_near_spectrum, PART_LEN1);
1361 if (delay_estimate >= 0) {
1362 // Update delay estimate buffer.
1363 aec->delay_histogram[delay_estimate]++;
1364 aec->num_delay_values++;
1365 }
1366 if (aec->delay_metrics_delivered == 1 &&
1367 aec->num_delay_values >= kDelayMetricsAggregationWindow) {
1368 UpdateDelayMetrics(aec);
1369 }
1370 }
1371 }
1372
1373 // Update the xfBuf block position.
1374 aec->xfBufBlockPos--;
1375 if (aec->xfBufBlockPos == -1) {
1376 aec->xfBufBlockPos = aec->num_partitions - 1;
1377 }
1378
1379 // Buffer xf
1380 memcpy(aec->xfBuf[0] + aec->xfBufBlockPos * PART_LEN1,
1381 xf_ptr,
1382 sizeof(float) * PART_LEN1);
1383 memcpy(aec->xfBuf[1] + aec->xfBufBlockPos * PART_LEN1,
1384 &xf_ptr[PART_LEN1],
1385 sizeof(float) * PART_LEN1);
1386
1387 // Perform echo subtraction.
1388 EchoSubtraction(aec,
1389 aec->num_partitions,
1390 aec->xfBufBlockPos,
1391 aec->metricsMode,
1392 aec->extended_filter_enabled,
1393 aec->normal_mu,
1394 aec->normal_error_threshold,
1395 aec->xfBuf,
1396 nearend_ptr,
1397 aec->xPow,
1398 aec->wfBuf,
1399 &aec->linoutlevel,
1400 echo_subtractor_output);
1401
1402 RTC_AEC_DEBUG_WAV_WRITE(aec->outLinearFile, echo_subtractor_output, PART_LEN);
1403
1404 // Perform echo suppression.
1405 EchoSuppression(aec, farend_ptr, echo_subtractor_output, output, outputH_ptr);
1406
1407 if (aec->metricsMode == 1) {
1408 // Update power levels and echo metrics
1409 UpdateLevel(&aec->farlevel, (float(*)[PART_LEN1])xf_ptr);
1410 UpdateLevel(&aec->nearlevel, df);
1411 UpdateMetrics(aec);
1412 }
1413
1414 // Store the output block.
1415 WebRtc_WriteBuffer(aec->outFrBuf, output, PART_LEN);
1416 // For high bands
1417 for (i = 0; i < aec->num_bands - 1; ++i) {
1418 WebRtc_WriteBuffer(aec->outFrBufH[i], outputH[i], PART_LEN);
1419 }
1420
1421 RTC_AEC_DEBUG_WAV_WRITE(aec->outFile, output, PART_LEN);
1422 }
1423
WebRtcAec_CreateAec()1424 AecCore* WebRtcAec_CreateAec() {
1425 int i;
1426 AecCore* aec = malloc(sizeof(AecCore));
1427 if (!aec) {
1428 return NULL;
1429 }
1430
1431 aec->nearFrBuf = WebRtc_CreateBuffer(FRAME_LEN + PART_LEN, sizeof(float));
1432 if (!aec->nearFrBuf) {
1433 WebRtcAec_FreeAec(aec);
1434 return NULL;
1435 }
1436
1437 aec->outFrBuf = WebRtc_CreateBuffer(FRAME_LEN + PART_LEN, sizeof(float));
1438 if (!aec->outFrBuf) {
1439 WebRtcAec_FreeAec(aec);
1440 return NULL;
1441 }
1442
1443 for (i = 0; i < NUM_HIGH_BANDS_MAX; ++i) {
1444 aec->nearFrBufH[i] = WebRtc_CreateBuffer(FRAME_LEN + PART_LEN,
1445 sizeof(float));
1446 if (!aec->nearFrBufH[i]) {
1447 WebRtcAec_FreeAec(aec);
1448 return NULL;
1449 }
1450 aec->outFrBufH[i] = WebRtc_CreateBuffer(FRAME_LEN + PART_LEN,
1451 sizeof(float));
1452 if (!aec->outFrBufH[i]) {
1453 WebRtcAec_FreeAec(aec);
1454 return NULL;
1455 }
1456 }
1457
1458 // Create far-end buffers.
1459 // For bit exactness with legacy code, each element in |far_time_buf| is
1460 // supposed to contain |PART_LEN2| samples with an overlap of |PART_LEN|
1461 // samples from the last frame.
1462 // TODO(minyue): reduce |far_time_buf| to non-overlapped |PART_LEN| samples.
1463 aec->far_time_buf =
1464 WebRtc_CreateBuffer(kBufSizePartitions, sizeof(float) * PART_LEN2);
1465 if (!aec->far_time_buf) {
1466 WebRtcAec_FreeAec(aec);
1467 return NULL;
1468 }
1469
1470 #ifdef WEBRTC_AEC_DEBUG_DUMP
1471 aec->instance_index = webrtc_aec_instance_count;
1472
1473 aec->farFile = aec->nearFile = aec->outFile = aec->outLinearFile = NULL;
1474 aec->debug_dump_count = 0;
1475 #endif
1476 aec->delay_estimator_farend =
1477 WebRtc_CreateDelayEstimatorFarend(PART_LEN1, kHistorySizeBlocks);
1478 if (aec->delay_estimator_farend == NULL) {
1479 WebRtcAec_FreeAec(aec);
1480 return NULL;
1481 }
1482 // We create the delay_estimator with the same amount of maximum lookahead as
1483 // the delay history size (kHistorySizeBlocks) for symmetry reasons.
1484 aec->delay_estimator = WebRtc_CreateDelayEstimator(
1485 aec->delay_estimator_farend, kHistorySizeBlocks);
1486 if (aec->delay_estimator == NULL) {
1487 WebRtcAec_FreeAec(aec);
1488 return NULL;
1489 }
1490 #ifdef WEBRTC_ANDROID
1491 aec->delay_agnostic_enabled = 1; // DA-AEC enabled by default.
1492 // DA-AEC assumes the system is causal from the beginning and will self adjust
1493 // the lookahead when shifting is required.
1494 WebRtc_set_lookahead(aec->delay_estimator, 0);
1495 #else
1496 aec->delay_agnostic_enabled = 0;
1497 WebRtc_set_lookahead(aec->delay_estimator, kLookaheadBlocks);
1498 #endif
1499 aec->extended_filter_enabled = 0;
1500
1501 // Assembly optimization
1502 WebRtcAec_FilterFar = FilterFar;
1503 WebRtcAec_ScaleErrorSignal = ScaleErrorSignal;
1504 WebRtcAec_FilterAdaptation = FilterAdaptation;
1505 WebRtcAec_OverdriveAndSuppress = OverdriveAndSuppress;
1506 WebRtcAec_ComfortNoise = ComfortNoise;
1507 WebRtcAec_SubbandCoherence = SubbandCoherence;
1508 WebRtcAec_StoreAsComplex = StoreAsComplex;
1509 WebRtcAec_PartitionDelay = PartitionDelay;
1510 WebRtcAec_WindowData = WindowData;
1511
1512
1513 #if defined(WEBRTC_ARCH_X86_FAMILY)
1514 if (WebRtc_GetCPUInfo(kSSE2)) {
1515 WebRtcAec_InitAec_SSE2();
1516 }
1517 #endif
1518
1519 #if defined(MIPS_FPU_LE)
1520 WebRtcAec_InitAec_mips();
1521 #endif
1522
1523 #if defined(WEBRTC_HAS_NEON)
1524 WebRtcAec_InitAec_neon();
1525 #elif defined(WEBRTC_DETECT_NEON)
1526 if ((WebRtc_GetCPUFeaturesARM() & kCPUFeatureNEON) != 0) {
1527 WebRtcAec_InitAec_neon();
1528 }
1529 #endif
1530
1531 aec_rdft_init();
1532
1533 return aec;
1534 }
1535
WebRtcAec_FreeAec(AecCore * aec)1536 void WebRtcAec_FreeAec(AecCore* aec) {
1537 int i;
1538 if (aec == NULL) {
1539 return;
1540 }
1541
1542 WebRtc_FreeBuffer(aec->nearFrBuf);
1543 WebRtc_FreeBuffer(aec->outFrBuf);
1544
1545 for (i = 0; i < NUM_HIGH_BANDS_MAX; ++i) {
1546 WebRtc_FreeBuffer(aec->nearFrBufH[i]);
1547 WebRtc_FreeBuffer(aec->outFrBufH[i]);
1548 }
1549
1550 WebRtc_FreeBuffer(aec->far_time_buf);
1551
1552 RTC_AEC_DEBUG_WAV_CLOSE(aec->farFile);
1553 RTC_AEC_DEBUG_WAV_CLOSE(aec->nearFile);
1554 RTC_AEC_DEBUG_WAV_CLOSE(aec->outFile);
1555 RTC_AEC_DEBUG_WAV_CLOSE(aec->outLinearFile);
1556 RTC_AEC_DEBUG_RAW_CLOSE(aec->e_fft_file);
1557
1558 WebRtc_FreeDelayEstimator(aec->delay_estimator);
1559 WebRtc_FreeDelayEstimatorFarend(aec->delay_estimator_farend);
1560
1561 free(aec);
1562 }
1563
WebRtcAec_InitAec(AecCore * aec,int sampFreq)1564 int WebRtcAec_InitAec(AecCore* aec, int sampFreq) {
1565 int i;
1566
1567 aec->sampFreq = sampFreq;
1568
1569 if (sampFreq == 8000) {
1570 aec->normal_mu = 0.6f;
1571 aec->normal_error_threshold = 2e-6f;
1572 aec->num_bands = 1;
1573 } else {
1574 aec->normal_mu = 0.5f;
1575 aec->normal_error_threshold = 1.5e-6f;
1576 aec->num_bands = (size_t)(sampFreq / 16000);
1577 }
1578
1579 WebRtc_InitBuffer(aec->nearFrBuf);
1580 WebRtc_InitBuffer(aec->outFrBuf);
1581 for (i = 0; i < NUM_HIGH_BANDS_MAX; ++i) {
1582 WebRtc_InitBuffer(aec->nearFrBufH[i]);
1583 WebRtc_InitBuffer(aec->outFrBufH[i]);
1584 }
1585
1586 // Initialize far-end buffers.
1587 WebRtc_InitBuffer(aec->far_time_buf);
1588
1589 #ifdef WEBRTC_AEC_DEBUG_DUMP
1590 {
1591 int process_rate = sampFreq > 16000 ? 16000 : sampFreq;
1592 RTC_AEC_DEBUG_WAV_REOPEN("aec_far", aec->instance_index,
1593 aec->debug_dump_count, process_rate,
1594 &aec->farFile );
1595 RTC_AEC_DEBUG_WAV_REOPEN("aec_near", aec->instance_index,
1596 aec->debug_dump_count, process_rate,
1597 &aec->nearFile);
1598 RTC_AEC_DEBUG_WAV_REOPEN("aec_out", aec->instance_index,
1599 aec->debug_dump_count, process_rate,
1600 &aec->outFile );
1601 RTC_AEC_DEBUG_WAV_REOPEN("aec_out_linear", aec->instance_index,
1602 aec->debug_dump_count, process_rate,
1603 &aec->outLinearFile);
1604 }
1605
1606 RTC_AEC_DEBUG_RAW_OPEN("aec_e_fft",
1607 aec->debug_dump_count,
1608 &aec->e_fft_file);
1609
1610 ++aec->debug_dump_count;
1611 #endif
1612 aec->system_delay = 0;
1613
1614 if (WebRtc_InitDelayEstimatorFarend(aec->delay_estimator_farend) != 0) {
1615 return -1;
1616 }
1617 if (WebRtc_InitDelayEstimator(aec->delay_estimator) != 0) {
1618 return -1;
1619 }
1620 aec->delay_logging_enabled = 0;
1621 aec->delay_metrics_delivered = 0;
1622 memset(aec->delay_histogram, 0, sizeof(aec->delay_histogram));
1623 aec->num_delay_values = 0;
1624 aec->delay_median = -1;
1625 aec->delay_std = -1;
1626 aec->fraction_poor_delays = -1.0f;
1627
1628 aec->signal_delay_correction = 0;
1629 aec->previous_delay = -2; // (-2): Uninitialized.
1630 aec->delay_correction_count = 0;
1631 aec->shift_offset = kInitialShiftOffset;
1632 aec->delay_quality_threshold = kDelayQualityThresholdMin;
1633
1634 aec->num_partitions = kNormalNumPartitions;
1635
1636 // Update the delay estimator with filter length. We use half the
1637 // |num_partitions| to take the echo path into account. In practice we say
1638 // that the echo has a duration of maximum half |num_partitions|, which is not
1639 // true, but serves as a crude measure.
1640 WebRtc_set_allowed_offset(aec->delay_estimator, aec->num_partitions / 2);
1641 // TODO(bjornv): I currently hard coded the enable. Once we've established
1642 // that AECM has no performance regression, robust_validation will be enabled
1643 // all the time and the APIs to turn it on/off will be removed. Hence, remove
1644 // this line then.
1645 WebRtc_enable_robust_validation(aec->delay_estimator, 1);
1646 aec->frame_count = 0;
1647
1648 // Default target suppression mode.
1649 aec->nlp_mode = 1;
1650
1651 // Sampling frequency multiplier w.r.t. 8 kHz.
1652 // In case of multiple bands we process the lower band in 16 kHz, hence the
1653 // multiplier is always 2.
1654 if (aec->num_bands > 1) {
1655 aec->mult = 2;
1656 } else {
1657 aec->mult = (short)aec->sampFreq / 8000;
1658 }
1659
1660 aec->farBufWritePos = 0;
1661 aec->farBufReadPos = 0;
1662
1663 aec->inSamples = 0;
1664 aec->outSamples = 0;
1665 aec->knownDelay = 0;
1666
1667 // Initialize buffers
1668 memset(aec->dBuf, 0, sizeof(aec->dBuf));
1669 memset(aec->eBuf, 0, sizeof(aec->eBuf));
1670 // For H bands
1671 for (i = 0; i < NUM_HIGH_BANDS_MAX; ++i) {
1672 memset(aec->dBufH[i], 0, sizeof(aec->dBufH[i]));
1673 }
1674
1675 memset(aec->xPow, 0, sizeof(aec->xPow));
1676 memset(aec->dPow, 0, sizeof(aec->dPow));
1677 memset(aec->dInitMinPow, 0, sizeof(aec->dInitMinPow));
1678 aec->noisePow = aec->dInitMinPow;
1679 aec->noiseEstCtr = 0;
1680
1681 // Initial comfort noise power
1682 for (i = 0; i < PART_LEN1; i++) {
1683 aec->dMinPow[i] = 1.0e6f;
1684 }
1685
1686 // Holds the last block written to
1687 aec->xfBufBlockPos = 0;
1688 // TODO: Investigate need for these initializations. Deleting them doesn't
1689 // change the output at all and yields 0.4% overall speedup.
1690 memset(aec->xfBuf, 0, sizeof(complex_t) * kExtendedNumPartitions * PART_LEN1);
1691 memset(aec->wfBuf, 0, sizeof(complex_t) * kExtendedNumPartitions * PART_LEN1);
1692 memset(aec->sde, 0, sizeof(complex_t) * PART_LEN1);
1693 memset(aec->sxd, 0, sizeof(complex_t) * PART_LEN1);
1694 memset(
1695 aec->xfwBuf, 0, sizeof(complex_t) * kExtendedNumPartitions * PART_LEN1);
1696 memset(aec->se, 0, sizeof(float) * PART_LEN1);
1697
1698 // To prevent numerical instability in the first block.
1699 for (i = 0; i < PART_LEN1; i++) {
1700 aec->sd[i] = 1;
1701 }
1702 for (i = 0; i < PART_LEN1; i++) {
1703 aec->sx[i] = 1;
1704 }
1705
1706 memset(aec->hNs, 0, sizeof(aec->hNs));
1707 memset(aec->outBuf, 0, sizeof(float) * PART_LEN);
1708
1709 aec->hNlFbMin = 1;
1710 aec->hNlFbLocalMin = 1;
1711 aec->hNlXdAvgMin = 1;
1712 aec->hNlNewMin = 0;
1713 aec->hNlMinCtr = 0;
1714 aec->overDrive = 2;
1715 aec->overDriveSm = 2;
1716 aec->delayIdx = 0;
1717 aec->stNearState = 0;
1718 aec->echoState = 0;
1719 aec->divergeState = 0;
1720
1721 aec->seed = 777;
1722 aec->delayEstCtr = 0;
1723
1724 aec->extreme_filter_divergence = 0;
1725
1726 // Metrics disabled by default
1727 aec->metricsMode = 0;
1728 InitMetrics(aec);
1729
1730 return 0;
1731 }
1732
1733
1734 // For bit exactness with a legacy code, |farend| is supposed to contain
1735 // |PART_LEN2| samples with an overlap of |PART_LEN| samples from the last
1736 // frame.
1737 // TODO(minyue): reduce |farend| to non-overlapped |PART_LEN| samples.
WebRtcAec_BufferFarendPartition(AecCore * aec,const float * farend)1738 void WebRtcAec_BufferFarendPartition(AecCore* aec, const float* farend) {
1739 // Check if the buffer is full, and in that case flush the oldest data.
1740 if (WebRtc_available_write(aec->far_time_buf) < 1) {
1741 WebRtcAec_MoveFarReadPtr(aec, 1);
1742 }
1743
1744 WebRtc_WriteBuffer(aec->far_time_buf, farend, 1);
1745 }
1746
WebRtcAec_MoveFarReadPtr(AecCore * aec,int elements)1747 int WebRtcAec_MoveFarReadPtr(AecCore* aec, int elements) {
1748 int elements_moved = WebRtc_MoveReadPtr(aec->far_time_buf, elements);
1749 aec->system_delay -= elements_moved * PART_LEN;
1750 return elements_moved;
1751 }
1752
WebRtcAec_ProcessFrames(AecCore * aec,const float * const * nearend,size_t num_bands,size_t num_samples,int knownDelay,float * const * out)1753 void WebRtcAec_ProcessFrames(AecCore* aec,
1754 const float* const* nearend,
1755 size_t num_bands,
1756 size_t num_samples,
1757 int knownDelay,
1758 float* const* out) {
1759 size_t i, j;
1760 int out_elements = 0;
1761
1762 aec->frame_count++;
1763 // For each frame the process is as follows:
1764 // 1) If the system_delay indicates on being too small for processing a
1765 // frame we stuff the buffer with enough data for 10 ms.
1766 // 2 a) Adjust the buffer to the system delay, by moving the read pointer.
1767 // b) Apply signal based delay correction, if we have detected poor AEC
1768 // performance.
1769 // 3) TODO(bjornv): Investigate if we need to add this:
1770 // If we can't move read pointer due to buffer size limitations we
1771 // flush/stuff the buffer.
1772 // 4) Process as many partitions as possible.
1773 // 5) Update the |system_delay| with respect to a full frame of FRAME_LEN
1774 // samples. Even though we will have data left to process (we work with
1775 // partitions) we consider updating a whole frame, since that's the
1776 // amount of data we input and output in audio_processing.
1777 // 6) Update the outputs.
1778
1779 // The AEC has two different delay estimation algorithms built in. The
1780 // first relies on delay input values from the user and the amount of
1781 // shifted buffer elements is controlled by |knownDelay|. This delay will
1782 // give a guess on how much we need to shift far-end buffers to align with
1783 // the near-end signal. The other delay estimation algorithm uses the
1784 // far- and near-end signals to find the offset between them. This one
1785 // (called "signal delay") is then used to fine tune the alignment, or
1786 // simply compensate for errors in the system based one.
1787 // Note that the two algorithms operate independently. Currently, we only
1788 // allow one algorithm to be turned on.
1789
1790 assert(aec->num_bands == num_bands);
1791
1792 for (j = 0; j < num_samples; j+= FRAME_LEN) {
1793 // TODO(bjornv): Change the near-end buffer handling to be the same as for
1794 // far-end, that is, with a near_pre_buf.
1795 // Buffer the near-end frame.
1796 WebRtc_WriteBuffer(aec->nearFrBuf, &nearend[0][j], FRAME_LEN);
1797 // For H band
1798 for (i = 1; i < num_bands; ++i) {
1799 WebRtc_WriteBuffer(aec->nearFrBufH[i - 1], &nearend[i][j], FRAME_LEN);
1800 }
1801
1802 // 1) At most we process |aec->mult|+1 partitions in 10 ms. Make sure we
1803 // have enough far-end data for that by stuffing the buffer if the
1804 // |system_delay| indicates others.
1805 if (aec->system_delay < FRAME_LEN) {
1806 // We don't have enough data so we rewind 10 ms.
1807 WebRtcAec_MoveFarReadPtr(aec, -(aec->mult + 1));
1808 }
1809
1810 if (!aec->delay_agnostic_enabled) {
1811 // 2 a) Compensate for a possible change in the system delay.
1812
1813 // TODO(bjornv): Investigate how we should round the delay difference;
1814 // right now we know that incoming |knownDelay| is underestimated when
1815 // it's less than |aec->knownDelay|. We therefore, round (-32) in that
1816 // direction. In the other direction, we don't have this situation, but
1817 // might flush one partition too little. This can cause non-causality,
1818 // which should be investigated. Maybe, allow for a non-symmetric
1819 // rounding, like -16.
1820 int move_elements = (aec->knownDelay - knownDelay - 32) / PART_LEN;
1821 int moved_elements =
1822 WebRtc_MoveReadPtr(aec->far_time_buf, move_elements);
1823 aec->knownDelay -= moved_elements * PART_LEN;
1824 } else {
1825 // 2 b) Apply signal based delay correction.
1826 int move_elements = SignalBasedDelayCorrection(aec);
1827 int moved_elements =
1828 WebRtc_MoveReadPtr(aec->far_time_buf, move_elements);
1829 int far_near_buffer_diff = WebRtc_available_read(aec->far_time_buf) -
1830 WebRtc_available_read(aec->nearFrBuf) / PART_LEN;
1831 WebRtc_SoftResetDelayEstimator(aec->delay_estimator, moved_elements);
1832 WebRtc_SoftResetDelayEstimatorFarend(aec->delay_estimator_farend,
1833 moved_elements);
1834 aec->signal_delay_correction += moved_elements;
1835 // If we rely on reported system delay values only, a buffer underrun here
1836 // can never occur since we've taken care of that in 1) above. Here, we
1837 // apply signal based delay correction and can therefore end up with
1838 // buffer underruns since the delay estimation can be wrong. We therefore
1839 // stuff the buffer with enough elements if needed.
1840 if (far_near_buffer_diff < 0) {
1841 WebRtcAec_MoveFarReadPtr(aec, far_near_buffer_diff);
1842 }
1843 }
1844
1845 // 4) Process as many blocks as possible.
1846 while (WebRtc_available_read(aec->nearFrBuf) >= PART_LEN) {
1847 ProcessBlock(aec);
1848 }
1849
1850 // 5) Update system delay with respect to the entire frame.
1851 aec->system_delay -= FRAME_LEN;
1852
1853 // 6) Update output frame.
1854 // Stuff the out buffer if we have less than a frame to output.
1855 // This should only happen for the first frame.
1856 out_elements = (int)WebRtc_available_read(aec->outFrBuf);
1857 if (out_elements < FRAME_LEN) {
1858 WebRtc_MoveReadPtr(aec->outFrBuf, out_elements - FRAME_LEN);
1859 for (i = 0; i < num_bands - 1; ++i) {
1860 WebRtc_MoveReadPtr(aec->outFrBufH[i], out_elements - FRAME_LEN);
1861 }
1862 }
1863 // Obtain an output frame.
1864 WebRtc_ReadBuffer(aec->outFrBuf, NULL, &out[0][j], FRAME_LEN);
1865 // For H bands.
1866 for (i = 1; i < num_bands; ++i) {
1867 WebRtc_ReadBuffer(aec->outFrBufH[i - 1], NULL, &out[i][j], FRAME_LEN);
1868 }
1869 }
1870 }
1871
WebRtcAec_GetDelayMetricsCore(AecCore * self,int * median,int * std,float * fraction_poor_delays)1872 int WebRtcAec_GetDelayMetricsCore(AecCore* self, int* median, int* std,
1873 float* fraction_poor_delays) {
1874 assert(self != NULL);
1875 assert(median != NULL);
1876 assert(std != NULL);
1877
1878 if (self->delay_logging_enabled == 0) {
1879 // Logging disabled.
1880 return -1;
1881 }
1882
1883 if (self->delay_metrics_delivered == 0) {
1884 UpdateDelayMetrics(self);
1885 self->delay_metrics_delivered = 1;
1886 }
1887 *median = self->delay_median;
1888 *std = self->delay_std;
1889 *fraction_poor_delays = self->fraction_poor_delays;
1890
1891 return 0;
1892 }
1893
WebRtcAec_echo_state(AecCore * self)1894 int WebRtcAec_echo_state(AecCore* self) { return self->echoState; }
1895
WebRtcAec_GetEchoStats(AecCore * self,Stats * erl,Stats * erle,Stats * a_nlp)1896 void WebRtcAec_GetEchoStats(AecCore* self,
1897 Stats* erl,
1898 Stats* erle,
1899 Stats* a_nlp) {
1900 assert(erl != NULL);
1901 assert(erle != NULL);
1902 assert(a_nlp != NULL);
1903 *erl = self->erl;
1904 *erle = self->erle;
1905 *a_nlp = self->aNlp;
1906 }
1907
WebRtcAec_SetConfigCore(AecCore * self,int nlp_mode,int metrics_mode,int delay_logging)1908 void WebRtcAec_SetConfigCore(AecCore* self,
1909 int nlp_mode,
1910 int metrics_mode,
1911 int delay_logging) {
1912 assert(nlp_mode >= 0 && nlp_mode < 3);
1913 self->nlp_mode = nlp_mode;
1914 self->metricsMode = metrics_mode;
1915 if (self->metricsMode) {
1916 InitMetrics(self);
1917 }
1918 // Turn on delay logging if it is either set explicitly or if delay agnostic
1919 // AEC is enabled (which requires delay estimates).
1920 self->delay_logging_enabled = delay_logging || self->delay_agnostic_enabled;
1921 if (self->delay_logging_enabled) {
1922 memset(self->delay_histogram, 0, sizeof(self->delay_histogram));
1923 }
1924 }
1925
WebRtcAec_enable_delay_agnostic(AecCore * self,int enable)1926 void WebRtcAec_enable_delay_agnostic(AecCore* self, int enable) {
1927 self->delay_agnostic_enabled = enable;
1928 }
1929
WebRtcAec_delay_agnostic_enabled(AecCore * self)1930 int WebRtcAec_delay_agnostic_enabled(AecCore* self) {
1931 return self->delay_agnostic_enabled;
1932 }
1933
WebRtcAec_enable_extended_filter(AecCore * self,int enable)1934 void WebRtcAec_enable_extended_filter(AecCore* self, int enable) {
1935 self->extended_filter_enabled = enable;
1936 self->num_partitions = enable ? kExtendedNumPartitions : kNormalNumPartitions;
1937 // Update the delay estimator with filter length. See InitAEC() for details.
1938 WebRtc_set_allowed_offset(self->delay_estimator, self->num_partitions / 2);
1939 }
1940
WebRtcAec_extended_filter_enabled(AecCore * self)1941 int WebRtcAec_extended_filter_enabled(AecCore* self) {
1942 return self->extended_filter_enabled;
1943 }
1944
WebRtcAec_system_delay(AecCore * self)1945 int WebRtcAec_system_delay(AecCore* self) { return self->system_delay; }
1946
WebRtcAec_SetSystemDelay(AecCore * self,int delay)1947 void WebRtcAec_SetSystemDelay(AecCore* self, int delay) {
1948 assert(delay >= 0);
1949 self->system_delay = delay;
1950 }
1951