wehub-resource-sync
66 lines
2.2 KiB
C++
66 lines
2.2 KiB
C++
/* Copyright 2018 The TensorFlow Authors. All Rights Reserved.
|
|
|
|
Licensed under the Apache License, Version 2.0 (the "License");
|
|
you may not use this file except in compliance with the License.
|
|
You may obtain a copy of the License at
|
|
|
|
http://www.apache.org/licenses/LICENSE-2.0
|
|
|
|
Unless required by applicable law or agreed to in writing, software
|
|
distributed under the License is distributed on an "AS IS" BASIS,
|
|
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
See the License for the specific language governing permissions and
|
|
limitations under the License.
|
|
==============================================================================*/
|
|
|
|
#include <math.h>
|
|
|
|
#include "tensorflow/lite/kernels/internal/mfcc.h"
|
|
|
|
namespace tflite {
|
|
namespace internal {
|
|
|
|
const double kDefaultUpperFrequencyLimit = 4000;
|
|
const double kDefaultLowerFrequencyLimit = 20;
|
|
const double kFilterbankFloor = 1e-12;
|
|
const int kDefaultFilterbankChannelCount = 40;
|
|
const int kDefaultDCTCoefficientCount = 13;
|
|
|
|
Mfcc::Mfcc()
|
|
: initialized_(false),
|
|
lower_frequency_limit_(kDefaultLowerFrequencyLimit),
|
|
upper_frequency_limit_(kDefaultUpperFrequencyLimit),
|
|
filterbank_channel_count_(kDefaultFilterbankChannelCount),
|
|
dct_coefficient_count_(kDefaultDCTCoefficientCount) {}
|
|
|
|
bool Mfcc::Initialize(int input_length, double input_sample_rate) {
|
|
bool initialized = mel_filterbank_.Initialize(
|
|
input_length, input_sample_rate, filterbank_channel_count_,
|
|
lower_frequency_limit_, upper_frequency_limit_);
|
|
initialized &=
|
|
dct_.Initialize(filterbank_channel_count_, dct_coefficient_count_);
|
|
initialized_ = initialized;
|
|
return initialized;
|
|
}
|
|
|
|
void Mfcc::Compute(const std::vector<double>& spectrogram_frame,
|
|
std::vector<double>* output) const {
|
|
if (!initialized_) {
|
|
// LOG(ERROR) << "Mfcc not initialized.";
|
|
return;
|
|
}
|
|
std::vector<double> working;
|
|
mel_filterbank_.Compute(spectrogram_frame, &working);
|
|
for (int i = 0; i < working.size(); ++i) {
|
|
double val = working[i];
|
|
if (val < kFilterbankFloor) {
|
|
val = kFilterbankFloor;
|
|
}
|
|
working[i] = log(val);
|
|
}
|
|
dct_.Compute(working, output);
|
|
}
|
|
|
|
} // namespace internal
|
|
} // namespace tflite
|