cf808d2366
This change instroduces a mode where the Accelerate operation will be more aggressive. When enabled, it will allow acceleration at lower correlation levels, and possibly remove multiple pitch periods at once. The feature is enabled through NetEq::Config, and is off by default. This means that bit-exactness tests are currently not affected. A unit test was added for the Accelerate class, with and without fast mode enabled. BUG=4691 R=minyue@webrtc.org Review URL: https://webrtc-codereview.appspot.com/50039004 Cr-Commit-Position: refs/heads/master@{#9295}
116 lines
4.5 KiB
C++
116 lines
4.5 KiB
C++
/*
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* Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "webrtc/modules/audio_coding/neteq/preemptive_expand.h"
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#include <algorithm> // min, max
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#include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
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namespace webrtc {
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PreemptiveExpand::ReturnCodes PreemptiveExpand::Process(
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const int16_t* input,
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int input_length,
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int old_data_length,
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AudioMultiVector* output,
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int16_t* length_change_samples) {
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old_data_length_per_channel_ = old_data_length;
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// Input length must be (almost) 30 ms.
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// Also, the new part must be at least |overlap_samples_| elements.
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static const int k15ms = 120; // 15 ms = 120 samples at 8 kHz sample rate.
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if (num_channels_ == 0 ||
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input_length / num_channels_ < (2 * k15ms - 1) * fs_mult_ ||
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old_data_length >= input_length / num_channels_ - overlap_samples_) {
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// Length of input data too short to do preemptive expand. Simply move all
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// data from input to output.
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output->PushBackInterleaved(input, input_length);
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return kError;
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}
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const bool kFastMode = false; // Fast mode is not available for PE Expand.
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return TimeStretch::Process(input, input_length, kFastMode, output,
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length_change_samples);
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}
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void PreemptiveExpand::SetParametersForPassiveSpeech(size_t len,
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int16_t* best_correlation,
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int* peak_index) const {
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// When the signal does not contain any active speech, the correlation does
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// not matter. Simply set it to zero.
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*best_correlation = 0;
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// For low energy expansion, the new data can be less than 15 ms,
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// but we must ensure that best_correlation is not larger than the length of
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// the new data.
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// but we must ensure that best_correlation is not larger than the new data.
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*peak_index = std::min(*peak_index,
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static_cast<int>(len - old_data_length_per_channel_));
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}
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PreemptiveExpand::ReturnCodes PreemptiveExpand::CheckCriteriaAndStretch(
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const int16_t* input,
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size_t input_length,
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size_t peak_index,
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int16_t best_correlation,
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bool active_speech,
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bool /*fast_mode*/,
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AudioMultiVector* output) const {
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// Pre-calculate common multiplication with |fs_mult_|.
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// 120 corresponds to 15 ms.
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int fs_mult_120 = fs_mult_ * 120;
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assert(old_data_length_per_channel_ >= 0); // Make sure it's been set.
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// Check for strong correlation (>0.9 in Q14) and at least 15 ms new data,
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// or passive speech.
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if (((best_correlation > kCorrelationThreshold) &&
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(old_data_length_per_channel_ <= fs_mult_120)) ||
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!active_speech) {
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// Do accelerate operation by overlap add.
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// Set length of the first part, not to be modified.
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size_t unmodified_length = std::max(old_data_length_per_channel_,
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fs_mult_120);
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// Copy first part, including cross-fade region.
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output->PushBackInterleaved(
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input, (unmodified_length + peak_index) * num_channels_);
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// Copy the last |peak_index| samples up to 15 ms to |temp_vector|.
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AudioMultiVector temp_vector(num_channels_);
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temp_vector.PushBackInterleaved(
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&input[(unmodified_length - peak_index) * num_channels_],
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peak_index * num_channels_);
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// Cross-fade |temp_vector| onto the end of |output|.
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output->CrossFade(temp_vector, peak_index);
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// Copy the last unmodified part, 15 ms + pitch period until the end.
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output->PushBackInterleaved(
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&input[unmodified_length * num_channels_],
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input_length - unmodified_length * num_channels_);
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if (active_speech) {
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return kSuccess;
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} else {
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return kSuccessLowEnergy;
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}
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} else {
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// Accelerate not allowed. Simply move all data from decoded to outData.
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output->PushBackInterleaved(input, input_length);
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return kNoStretch;
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}
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}
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PreemptiveExpand* PreemptiveExpandFactory::Create(
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int sample_rate_hz,
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size_t num_channels,
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const BackgroundNoise& background_noise,
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int overlap_samples) const {
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return new PreemptiveExpand(
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sample_rate_hz, num_channels, background_noise, overlap_samples);
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}
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} // namespace webrtc
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