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/*
* Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "modules/audio_coding/codecs/cng/webrtc_cng.h"
#include <algorithm>
#include "common_audio/signal_processing/include/signal_processing_library.h"
#include "rtc_base/checks.h"
#include "rtc_base/numerics/safe_conversions.h"
namespace webrtc {
namespace {
const size_t kCngMaxOutsizeOrder = 640;
// TODO(ossu): Rename the left-over WebRtcCng according to style guide.
void WebRtcCng_K2a16(int16_t* k, int useOrder, int16_t* a);
const int32_t WebRtcCng_kDbov[94] = {
1081109975, 858756178, 682134279, 541838517, 430397633, 341876992,
271562548, 215709799, 171344384, 136103682, 108110997, 85875618,
68213428, 54183852, 43039763, 34187699, 27156255, 21570980,
17134438, 13610368, 10811100, 8587562, 6821343, 5418385,
4303976, 3418770, 2715625, 2157098, 1713444, 1361037,
1081110, 858756, 682134, 541839, 430398, 341877,
271563, 215710, 171344, 136104, 108111, 85876,
68213, 54184, 43040, 34188, 27156, 21571,
17134, 13610, 10811, 8588, 6821, 5418,
4304, 3419, 2716, 2157, 1713, 1361,
1081, 859, 682, 542, 430, 342,
272, 216, 171, 136, 108, 86,
68, 54, 43, 34, 27, 22,
17, 14, 11, 9, 7, 5,
4, 3, 3, 2, 2, 1,
1, 1, 1, 1};
const int16_t WebRtcCng_kCorrWindow[WEBRTC_CNG_MAX_LPC_ORDER] = {
32702, 32636, 32570, 32505, 32439, 32374,
32309, 32244, 32179, 32114, 32049, 31985};
} // namespace
ComfortNoiseDecoder::ComfortNoiseDecoder() {
/* Needed to get the right function pointers in SPLIB. */
Reset();
}
void ComfortNoiseDecoder::Reset() {
dec_seed_ = 7777; /* For debugging only. */
dec_target_energy_ = 0;
dec_used_energy_ = 0;
for (auto& c : dec_target_reflCoefs_)
c = 0;
for (auto& c : dec_used_reflCoefs_)
c = 0;
for (auto& c : dec_filtstate_)
c = 0;
for (auto& c : dec_filtstateLow_)
c = 0;
dec_order_ = 5;
dec_target_scale_factor_ = 0;
dec_used_scale_factor_ = 0;
}
void ComfortNoiseDecoder::UpdateSid(rtc::ArrayView<const uint8_t> sid) {
int16_t refCs[WEBRTC_CNG_MAX_LPC_ORDER];
int32_t targetEnergy;
size_t length = sid.size();
/* Throw away reflection coefficients of higher order than we can handle. */
if (length > (WEBRTC_CNG_MAX_LPC_ORDER + 1))
length = WEBRTC_CNG_MAX_LPC_ORDER + 1;
dec_order_ = static_cast<uint16_t>(length - 1);
uint8_t sid0 = std::min<uint8_t>(sid[0], 93);
targetEnergy = WebRtcCng_kDbov[sid0];
/* Take down target energy to 75%. */
targetEnergy = targetEnergy >> 1;
targetEnergy += targetEnergy >> 2;
dec_target_energy_ = targetEnergy;
/* Reconstruct coeffs with tweak for WebRtc implementation of RFC3389. */
if (dec_order_ == WEBRTC_CNG_MAX_LPC_ORDER) {
for (size_t i = 0; i < (dec_order_); i++) {
refCs[i] = sid[i + 1] << 8; /* Q7 to Q15*/
dec_target_reflCoefs_[i] = refCs[i];
}
} else {
for (size_t i = 0; i < (dec_order_); i++) {
refCs[i] = (sid[i + 1] - 127) * (1 << 8); /* Q7 to Q15. */
dec_target_reflCoefs_[i] = refCs[i];
}
}
for (size_t i = (dec_order_); i < WEBRTC_CNG_MAX_LPC_ORDER; i++) {
refCs[i] = 0;
dec_target_reflCoefs_[i] = refCs[i];
}
}
bool ComfortNoiseDecoder::Generate(rtc::ArrayView<int16_t> out_data,
bool new_period) {
int16_t excitation[kCngMaxOutsizeOrder];
int16_t low[kCngMaxOutsizeOrder];
int16_t lpPoly[WEBRTC_CNG_MAX_LPC_ORDER + 1];
int16_t ReflBetaStd = 26214; /* 0.8 in q15. */
int16_t ReflBetaCompStd = 6553; /* 0.2 in q15. */
int16_t ReflBetaNewP = 19661; /* 0.6 in q15. */
int16_t ReflBetaCompNewP = 13107; /* 0.4 in q15. */
int16_t Beta, BetaC; /* These are in Q15. */
int32_t targetEnergy;
int16_t En;
int16_t temp16;
const size_t num_samples = out_data.size();
if (num_samples > kCngMaxOutsizeOrder) {
return false;
}
if (new_period) {
dec_used_scale_factor_ = dec_target_scale_factor_;
Beta = ReflBetaNewP;
BetaC = ReflBetaCompNewP;
} else {
Beta = ReflBetaStd;
BetaC = ReflBetaCompStd;
}
/* Calculate new scale factor in Q13 */
dec_used_scale_factor_ = rtc::checked_cast<int16_t>(
WEBRTC_SPL_MUL_16_16_RSFT(dec_used_scale_factor_, Beta >> 2, 13) +
WEBRTC_SPL_MUL_16_16_RSFT(dec_target_scale_factor_, BetaC >> 2, 13));
dec_used_energy_ = dec_used_energy_ >> 1;
dec_used_energy_ += dec_target_energy_ >> 1;
/* Do the same for the reflection coeffs, albeit in Q15. */
for (size_t i = 0; i < WEBRTC_CNG_MAX_LPC_ORDER; i++) {
dec_used_reflCoefs_[i] =
(int16_t)WEBRTC_SPL_MUL_16_16_RSFT(dec_used_reflCoefs_[i], Beta, 15);
dec_used_reflCoefs_[i] +=
(int16_t)WEBRTC_SPL_MUL_16_16_RSFT(dec_target_reflCoefs_[i], BetaC, 15);
}
/* Compute the polynomial coefficients. */
WebRtcCng_K2a16(dec_used_reflCoefs_, WEBRTC_CNG_MAX_LPC_ORDER, lpPoly);
targetEnergy = dec_used_energy_;
/* Calculate scaling factor based on filter energy. */
En = 8192; /* 1.0 in Q13. */
for (size_t i = 0; i < (WEBRTC_CNG_MAX_LPC_ORDER); i++) {
/* Floating point value for reference.
E *= 1.0 - (dec_used_reflCoefs_[i] / 32768.0) *
(dec_used_reflCoefs_[i] / 32768.0);
*/
/* Same in fixed point. */
/* K(i).^2 in Q15. */
temp16 = (int16_t)WEBRTC_SPL_MUL_16_16_RSFT(dec_used_reflCoefs_[i],
dec_used_reflCoefs_[i], 15);
/* 1 - K(i).^2 in Q15. */
temp16 = 0x7fff - temp16;
En = (int16_t)WEBRTC_SPL_MUL_16_16_RSFT(En, temp16, 15);
}
/* float scaling= sqrt(E * dec_target_energy_ / (1 << 24)); */
/* Calculate sqrt(En * target_energy / excitation energy) */
targetEnergy = WebRtcSpl_Sqrt(dec_used_energy_);
En = (int16_t)WebRtcSpl_Sqrt(En) << 6;
En = (En * 3) >> 1; /* 1.5 estimates sqrt(2). */
dec_used_scale_factor_ = (int16_t)((En * targetEnergy) >> 12);
/* Generate excitation. */
/* Excitation energy per sample is 2.^24 - Q13 N(0,1). */
for (size_t i = 0; i < num_samples; i++) {
excitation[i] = WebRtcSpl_RandN(&dec_seed_) >> 1;
}
/* Scale to correct energy. */
WebRtcSpl_ScaleVector(excitation, excitation, dec_used_scale_factor_,
num_samples, 13);
/* `lpPoly` - Coefficients in Q12.
* `excitation` - Speech samples.
* `nst->dec_filtstate` - State preservation.
* `out_data` - Filtered speech samples. */
WebRtcSpl_FilterAR(lpPoly, WEBRTC_CNG_MAX_LPC_ORDER + 1, excitation,
num_samples, dec_filtstate_, WEBRTC_CNG_MAX_LPC_ORDER,
dec_filtstateLow_, WEBRTC_CNG_MAX_LPC_ORDER,
out_data.data(), low, num_samples);
return true;
}
ComfortNoiseEncoder::ComfortNoiseEncoder(int fs, int interval, int quality)
: enc_nrOfCoefs_(quality),
enc_sampfreq_(fs),
enc_interval_(interval),
enc_msSinceSid_(0),
enc_Energy_(0),
enc_reflCoefs_{0},
enc_corrVector_{0},
enc_seed_(7777) /* For debugging only. */ {
RTC_CHECK_GT(quality, 0);
RTC_CHECK_LE(quality, WEBRTC_CNG_MAX_LPC_ORDER);
}
void ComfortNoiseEncoder::Reset(int fs, int interval, int quality) {
RTC_CHECK_GT(quality, 0);
RTC_CHECK_LE(quality, WEBRTC_CNG_MAX_LPC_ORDER);
enc_nrOfCoefs_ = quality;
enc_sampfreq_ = fs;
enc_interval_ = interval;
enc_msSinceSid_ = 0;
enc_Energy_ = 0;
for (auto& c : enc_reflCoefs_)
c = 0;
for (auto& c : enc_corrVector_)
c = 0;
enc_seed_ = 7777; /* For debugging only. */
}
size_t ComfortNoiseEncoder::Encode(rtc::ArrayView<const int16_t> speech,
bool force_sid,
rtc::Buffer* output) {
int16_t arCoefs[WEBRTC_CNG_MAX_LPC_ORDER + 1];
int32_t corrVector[WEBRTC_CNG_MAX_LPC_ORDER + 1];
int16_t refCs[WEBRTC_CNG_MAX_LPC_ORDER + 1];
int16_t hanningW[kCngMaxOutsizeOrder];
int16_t ReflBeta = 19661; /* 0.6 in q15. */
int16_t ReflBetaComp = 13107; /* 0.4 in q15. */
int32_t outEnergy;
int outShifts;
size_t i;
int stab;
int acorrScale;
size_t index;
size_t ind, factor;
int32_t* bptr;
int32_t blo, bhi;
int16_t negate;
const int16_t* aptr;
int16_t speechBuf[kCngMaxOutsizeOrder];
const size_t num_samples = speech.size();
RTC_CHECK_LE(num_samples, kCngMaxOutsizeOrder);
for (i = 0; i < num_samples; i++) {
speechBuf[i] = speech[i];
}
factor = num_samples;
/* Calculate energy and a coefficients. */
outEnergy = WebRtcSpl_Energy(speechBuf, num_samples, &outShifts);
while (outShifts > 0) {
/* We can only do 5 shifts without destroying accuracy in
* division factor. */
if (outShifts > 5) {
outEnergy <<= (outShifts - 5);
outShifts = 5;
} else {
factor /= 2;
outShifts--;
}
}
outEnergy = WebRtcSpl_DivW32W16(outEnergy, (int16_t)factor);
if (outEnergy > 1) {
/* Create Hanning Window. */
WebRtcSpl_GetHanningWindow(hanningW, num_samples / 2);
for (i = 0; i < (num_samples / 2); i++)
hanningW[num_samples - i - 1] = hanningW[i];
WebRtcSpl_ElementwiseVectorMult(speechBuf, hanningW, speechBuf, num_samples,
14);
WebRtcSpl_AutoCorrelation(speechBuf, num_samples, enc_nrOfCoefs_,
corrVector, &acorrScale);
if (*corrVector == 0)
*corrVector = WEBRTC_SPL_WORD16_MAX;
/* Adds the bandwidth expansion. */
aptr = WebRtcCng_kCorrWindow;
bptr = corrVector;
/* (zzz) lpc16_1 = 17+1+820+2+2 = 842 (ordo2=700). */
for (ind = 0; ind < enc_nrOfCoefs_; ind++) {
/* The below code multiplies the 16 b corrWindow values (Q15) with
* the 32 b corrvector (Q0) and shifts the result down 15 steps. */
negate = *bptr < 0;
if (negate)
*bptr = -*bptr;
blo = (int32_t)*aptr * (*bptr & 0xffff);
bhi = ((blo >> 16) & 0xffff) +
((int32_t)(*aptr++) * ((*bptr >> 16) & 0xffff));
blo = (blo & 0xffff) | ((bhi & 0xffff) << 16);
*bptr = (((bhi >> 16) & 0x7fff) << 17) | ((uint32_t)blo >> 15);
if (negate)
*bptr = -*bptr;
bptr++;
}
/* End of bandwidth expansion. */
stab = WebRtcSpl_LevinsonDurbin(corrVector, arCoefs, refCs, enc_nrOfCoefs_);
if (!stab) {
/* Disregard from this frame */
return 0;
}
} else {
for (i = 0; i < enc_nrOfCoefs_; i++)
refCs[i] = 0;
}
if (force_sid) {
/* Read instantaneous values instead of averaged. */
for (i = 0; i < enc_nrOfCoefs_; i++)
enc_reflCoefs_[i] = refCs[i];
enc_Energy_ = outEnergy;
} else {
/* Average history with new values. */
for (i = 0; i < enc_nrOfCoefs_; i++) {
enc_reflCoefs_[i] =
(int16_t)WEBRTC_SPL_MUL_16_16_RSFT(enc_reflCoefs_[i], ReflBeta, 15);
enc_reflCoefs_[i] +=
(int16_t)WEBRTC_SPL_MUL_16_16_RSFT(refCs[i], ReflBetaComp, 15);
}
enc_Energy_ = (outEnergy >> 2) + (enc_Energy_ >> 1) + (enc_Energy_ >> 2);
}
if (enc_Energy_ < 1) {
enc_Energy_ = 1;
}
if ((enc_msSinceSid_ > (enc_interval_ - 1)) || force_sid) {
/* Search for best dbov value. */
index = 0;
for (i = 1; i < 93; i++) {
/* Always round downwards. */
if ((enc_Energy_ - WebRtcCng_kDbov[i]) > 0) {
index = i;
break;
}
}
if ((i == 93) && (index == 0))
index = 94;
const size_t output_coefs = enc_nrOfCoefs_ + 1;
output->AppendData(output_coefs, [&](rtc::ArrayView<uint8_t> output) {
output[0] = (uint8_t)index;
/* Quantize coefficients with tweak for WebRtc implementation of
* RFC3389. */
if (enc_nrOfCoefs_ == WEBRTC_CNG_MAX_LPC_ORDER) {
for (i = 0; i < enc_nrOfCoefs_; i++) {
/* Q15 to Q7 with rounding. */
output[i + 1] = ((enc_reflCoefs_[i] + 128) >> 8);
}
} else {
for (i = 0; i < enc_nrOfCoefs_; i++) {
/* Q15 to Q7 with rounding. */
output[i + 1] = (127 + ((enc_reflCoefs_[i] + 128) >> 8));
}
}
return output_coefs;
});
enc_msSinceSid_ =
static_cast<int16_t>((1000 * num_samples) / enc_sampfreq_);
return output_coefs;
} else {
enc_msSinceSid_ +=
static_cast<int16_t>((1000 * num_samples) / enc_sampfreq_);
return 0;
}
}
namespace {
/* Values in `k` are Q15, and `a` Q12. */
void WebRtcCng_K2a16(int16_t* k, int useOrder, int16_t* a) {
int16_t any[WEBRTC_SPL_MAX_LPC_ORDER + 1];
int16_t* aptr;
int16_t* aptr2;
int16_t* anyptr;
const int16_t* kptr;
int m, i;
kptr = k;
*a = 4096; /* i.e., (Word16_MAX >> 3) + 1 */
*any = *a;
a[1] = (*k + 4) >> 3;
for (m = 1; m < useOrder; m++) {
kptr++;
aptr = a;
aptr++;
aptr2 = &a[m];
anyptr = any;
anyptr++;
any[m + 1] = (*kptr + 4) >> 3;
for (i = 0; i < m; i++) {
*anyptr++ =
(*aptr++) +
(int16_t)((((int32_t)(*aptr2--) * (int32_t)*kptr) + 16384) >> 15);
}
aptr = a;
anyptr = any;
for (i = 0; i < (m + 2); i++) {
*aptr++ = *anyptr++;
}
}
}
} // namespace
} // namespace webrtc