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Further refactored the echo suppressor code:

Browse Source 
-Extended the InverseFft function to be more generally
 applicable.
-Included the previous external extra scaling into the
 preexisting InverseFft call.
-Moved the updating of aec->delayEstCtr to where it is
 actually used.
-Refactored the output production and comfort noise
 addition using the InverseFft function.
-Removed the if-statements checking the value of the
 constant flagHbandCn as any value different from 1 would
 crash the program. Also removed the constant

The changes have been tested for bitexactness.

BUG=webrtc:5201

Review URL: https://codereview.webrtc.org/1492343002

Cr-Commit-Position: refs/heads/master@{#11054}
This commit is contained in:
peah
2015-12-16 08:11:15 -08:00
committed by Commit bot
parent c482eb3c84
commit 0bc176b99b
2 changed files with 39 additions and 60 deletions
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96
webrtc/modules/audio_processing/aec/aec_core.c
View File

@ -44,7 +44,6 @@ static const int countLen = 50;
static const int kDelayMetricsAggregationWindow = 1250; // 5 seconds at 16 kHz.
// Quantities to control H band scaling for SWB input
static const int flagHbandCn = 1; // flag for adding comfort noise in H band
static const float cnScaleHband =
(float)0.4; // scale for comfort noise in H band
// Initial bin for averaging nlp gain in low band
@ -483,7 +482,7 @@ static void ComfortNoise(AecCore* aec,
noiseAvg = 0.0;
tmpAvg = 0.0;
num = 0;
if (aec->num_bands > 1 && flagHbandCn == 1) {
if (aec->num_bands > 1) {
// average noise scale
// average over second half of freq spectrum (i.e., 4->8khz)
@ -814,15 +813,18 @@ static void UpdateDelayMetrics(AecCore* self) {
return;
}
static void InverseFft(float freq_data[2][PART_LEN1],
float time_data[PART_LEN2]) {
static void ScaledInverseFft(float freq_data[2][PART_LEN1],
float time_data[PART_LEN2],
float scale,
int conjugate) {
int i;
const float scale = 1.0f / PART_LEN2;
time_data[0] = freq_data[0][0] * scale;
time_data[1] = freq_data[0][PART_LEN] * scale;
const float normalization = scale / ((float)PART_LEN2);
const float sign = (conjugate ? -1 : 1);
time_data[0] = freq_data[0][0] * normalization;
time_data[1] = freq_data[0][PART_LEN] * normalization;
for (i = 1; i < PART_LEN; i++) {
time_data[2 * i] = freq_data[0][i] * scale;
time_data[2 * i + 1] = freq_data[1][i] * scale;
time_data[2 * i] = freq_data[0][i] * normalization;
time_data[2 * i + 1] = sign * freq_data[1][i] * normalization;
}
aec_rdft_inverse_128(time_data);
}
@ -963,11 +965,8 @@ static void EchoSubtraction(
s_fft);
// Compute the time-domain echo estimate s.
InverseFft(s_fft, s_extended);
ScaledInverseFft(s_fft, s_extended, 2.0f, 0);
s = &s_extended[PART_LEN];
for (i = 0; i < PART_LEN; ++i) {
s[i] *= 2.0f;
}
// Compute the time-domain echo prediction error.
for (i = 0; i < PART_LEN; ++i) {
@ -1014,7 +1013,6 @@ static void EchoSuppression(AecCore* aec,
float dfw[2][PART_LEN1];
float comfortNoiseHband[2][PART_LEN1];
float fft[PART_LEN2];
float scale, dtmp;
float nlpGainHband;
int i;
size_t j;
@ -1054,11 +1052,6 @@ static void EchoSuppression(AecCore* aec,
aec_rdft_forward_128(fft);
StoreAsComplex(fft, efw);
aec->delayEstCtr++;
if (aec->delayEstCtr == delayEstInterval) {
aec->delayEstCtr = 0;
}
// We should always have at least one element stored in |far_buf|.
assert(WebRtc_available_read(aec->far_buf_windowed) > 0);
// NLP
@ -1069,8 +1062,11 @@ static void EchoSuppression(AecCore* aec,
// Buffer far.
memcpy(aec->xfwBuf, xfw_ptr, sizeof(float) * 2 * PART_LEN1);
if (aec->delayEstCtr == 0)
aec->delayEstCtr++;
if (aec->delayEstCtr == delayEstInterval) {
aec->delayEstCtr = 0;
aec->delayIdx = WebRtcAec_PartitionDelay(aec);
}
// Use delayed far.
memcpy(xfw,
@ -1190,67 +1186,51 @@ static void EchoSuppression(AecCore* aec,
// scaling only in UpdateMetrics().
UpdateLevel(&aec->nlpoutlevel, efw);
}
// Inverse error fft.
fft[0] = efw[0][0];
fft[1] = efw[0][PART_LEN];
for (i = 1; i < PART_LEN; i++) {
fft[2 * i] = efw[0][i];
// Sign change required by Ooura fft.
fft[2 * i + 1] = -efw[1][i];
}
aec_rdft_inverse_128(fft);
ScaledInverseFft(efw, fft, 2.0f, 1);
// Overlap and add to obtain output.
scale = 2.0f / PART_LEN2;
for (i = 0; i < PART_LEN; i++) {
fft[i] *= scale; // fft scaling
fft[i] = fft[i] * WebRtcAec_sqrtHanning[i] + aec->outBuf[i];
fft[PART_LEN + i] *= scale; // fft scaling
aec->outBuf[i] = fft[PART_LEN + i] * WebRtcAec_sqrtHanning[PART_LEN - i];
output[i] = (fft[i] * WebRtcAec_sqrtHanning[i] +
aec->outBuf[i] * WebRtcAec_sqrtHanning[PART_LEN - i]);
// Saturate output to keep it in the allowed range.
output[i] = WEBRTC_SPL_SAT(
WEBRTC_SPL_WORD16_MAX, fft[i], WEBRTC_SPL_WORD16_MIN);
WEBRTC_SPL_WORD16_MAX, output[i], WEBRTC_SPL_WORD16_MIN);
}
memcpy(aec->outBuf, &fft[PART_LEN], PART_LEN * sizeof(aec->outBuf[0]));
// For H band
if (aec->num_bands > 1) {
// H band gain
// average nlp over low band: average over second half of freq spectrum
// (4->8khz)
GetHighbandGain(hNl, &nlpGainHband);
// Inverse comfort_noise
if (flagHbandCn == 1) {
fft[0] = comfortNoiseHband[0][0];
fft[1] = comfortNoiseHband[0][PART_LEN];
for (i = 1; i < PART_LEN; i++) {
fft[2 * i] = comfortNoiseHband[0][i];
fft[2 * i + 1] = comfortNoiseHband[1][i];
}
aec_rdft_inverse_128(fft);
scale = 2.0f / PART_LEN2;
}
ScaledInverseFft(comfortNoiseHband, fft, 2.0f, 0);
// compute gain factor
for (j = 0; j < aec->num_bands - 1; ++j) {
for (i = 0; i < PART_LEN; i++) {
dtmp = aec->dBufH[j][i];
dtmp = dtmp * nlpGainHband; // for variable gain
// add some comfort noise where Hband is attenuated
if (flagHbandCn == 1 && j == 0) {
fft[i] *= scale; // fft scaling
dtmp += cnScaleHband * fft[i];
}
// Saturate output to keep it in the allowed range.
outputH[j][i] = WEBRTC_SPL_SAT(
WEBRTC_SPL_WORD16_MAX, dtmp, WEBRTC_SPL_WORD16_MIN);
outputH[j][i] = aec->dBufH[j][i] * nlpGainHband;
}
}
// Add some comfort noise where Hband is attenuated.
for (i = 0; i < PART_LEN; i++) {
outputH[0][i] += cnScaleHband * fft[i];
}
// Saturate output to keep it in the allowed range.
for (j = 0; j < aec->num_bands - 1; ++j) {
for (i = 0; i < PART_LEN; i++) {
outputH[j][i] = WEBRTC_SPL_SAT(
WEBRTC_SPL_WORD16_MAX, outputH[j][i], WEBRTC_SPL_WORD16_MIN);
}
}
}
// Copy the current block to the old position.

3
webrtc/modules/audio_processing/aec/aec_core_mips.c
View File

@ -20,7 +20,6 @@
#include "webrtc/modules/audio_processing/aec/aec_core_internal.h"
#include "webrtc/modules/audio_processing/aec/aec_rdft.h"
static const int flagHbandCn = 1; // flag for adding comfort noise in H band
extern const float WebRtcAec_weightCurve[65];
extern const float WebRtcAec_overDriveCurve[65];
@ -274,7 +273,7 @@ void WebRtcAec_ComfortNoise_mips(AecCore* aec,
noiseAvg = 0.0;
tmpAvg = 0.0;
num = 0;
if (aec->num_bands > 1 && flagHbandCn == 1) {
if (aec->num_bands > 1) {
for (i = 0; i < PART_LEN; i++) {
rand[i] = ((float)randW16[i]) / 32768;
}