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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/neteq/comfort_noise.h"
#include <cstdint>
#include <memory>
#include "api/array_view.h"
#include "modules/audio_coding/codecs/cng/webrtc_cng.h"
#include "modules/audio_coding/neteq/audio_multi_vector.h"
#include "modules/audio_coding/neteq/audio_vector.h"
#include "modules/audio_coding/neteq/decoder_database.h"
#include "modules/audio_coding/neteq/dsp_helper.h"
#include "modules/audio_coding/neteq/sync_buffer.h"
#include "rtc_base/buffer.h"
#include "rtc_base/checks.h"
#include "rtc_base/logging.h"
namespace webrtc {
void ComfortNoise::Reset() {
first_call_ = true;
}
int ComfortNoise::UpdateParameters(const Packet& packet) {
// Get comfort noise decoder.
if (decoder_database_->SetActiveCngDecoder(packet.payload_type) != kOK) {
return kUnknownPayloadType;
}
ComfortNoiseDecoder* cng_decoder = decoder_database_->GetActiveCngDecoder();
RTC_DCHECK(cng_decoder);
cng_decoder->UpdateSid(packet.payload);
return kOK;
}
int ComfortNoise::Generate(size_t requested_length, AudioMultiVector* output) {
// TODO(hlundin): Change to an enumerator and skip assert.
RTC_DCHECK(fs_hz_ == 8000 || fs_hz_ == 16000 || fs_hz_ == 32000 ||
fs_hz_ == 48000);
// Not adapted for multi-channel yet.
if (output->Channels() != 1) {
RTC_LOG(LS_ERROR) << "No multi-channel support";
return kMultiChannelNotSupported;
}
size_t number_of_samples = requested_length;
bool new_period = false;
if (first_call_) {
// Generate noise and overlap slightly with old data.
number_of_samples = requested_length + overlap_length_;
new_period = true;
}
output->AssertSize(number_of_samples);
// Get the decoder from the database.
ComfortNoiseDecoder* cng_decoder = decoder_database_->GetActiveCngDecoder();
if (!cng_decoder) {
RTC_LOG(LS_ERROR) << "Unknwown payload type";
return kUnknownPayloadType;
}
std::unique_ptr<int16_t[]> temp(new int16_t[number_of_samples]);
if (!cng_decoder->Generate(
rtc::ArrayView<int16_t>(temp.get(), number_of_samples), new_period)) {
// Error returned.
output->Zeros(requested_length);
RTC_LOG(LS_ERROR)
<< "ComfortNoiseDecoder::Genererate failed to generate comfort noise";
return kInternalError;
}
(*output)[0].OverwriteAt(temp.get(), number_of_samples, 0);
if (first_call_) {
// Set tapering window parameters. Values are in Q15.
int16_t muting_window; // Mixing factor for overlap data.
int16_t muting_window_increment; // Mixing factor increment (negative).
int16_t unmuting_window; // Mixing factor for comfort noise.
int16_t unmuting_window_increment; // Mixing factor increment.
if (fs_hz_ == 8000) {
muting_window = DspHelper::kMuteFactorStart8kHz;
muting_window_increment = DspHelper::kMuteFactorIncrement8kHz;
unmuting_window = DspHelper::kUnmuteFactorStart8kHz;
unmuting_window_increment = DspHelper::kUnmuteFactorIncrement8kHz;
} else if (fs_hz_ == 16000) {
muting_window = DspHelper::kMuteFactorStart16kHz;
muting_window_increment = DspHelper::kMuteFactorIncrement16kHz;
unmuting_window = DspHelper::kUnmuteFactorStart16kHz;
unmuting_window_increment = DspHelper::kUnmuteFactorIncrement16kHz;
} else if (fs_hz_ == 32000) {
muting_window = DspHelper::kMuteFactorStart32kHz;
muting_window_increment = DspHelper::kMuteFactorIncrement32kHz;
unmuting_window = DspHelper::kUnmuteFactorStart32kHz;
unmuting_window_increment = DspHelper::kUnmuteFactorIncrement32kHz;
} else { // fs_hz_ == 48000
muting_window = DspHelper::kMuteFactorStart48kHz;
muting_window_increment = DspHelper::kMuteFactorIncrement48kHz;
unmuting_window = DspHelper::kUnmuteFactorStart48kHz;
unmuting_window_increment = DspHelper::kUnmuteFactorIncrement48kHz;
}
// Do overlap-add between new vector and overlap.
size_t start_ix = sync_buffer_->Size() - overlap_length_;
for (size_t i = 0; i < overlap_length_; i++) {
/* overlapVec[i] = WinMute * overlapVec[i] + WinUnMute * outData[i] */
// The expression (*output)[0][i] is the i-th element in the first
// channel.
(*sync_buffer_)[0][start_ix + i] =
(((*sync_buffer_)[0][start_ix + i] * muting_window) +
((*output)[0][i] * unmuting_window) + 16384) >>
15;
muting_window += muting_window_increment;
unmuting_window += unmuting_window_increment;
}
// Remove `overlap_length_` samples from the front of `output` since they
// were mixed into `sync_buffer_` above.
output->PopFront(overlap_length_);
}
first_call_ = false;
return kOK;
}
} // namespace webrtc