chromium/third_party/tflite/src/tensorflow/lite/kernels/internal/spectrogram.cc

/* 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 "tensorflow/lite/kernels/internal/spectrogram.h"

#include <assert.h>
#include <math.h>
#include <stdint.h>

#include "third_party/fft2d/fft.h"

namespace tflite {
namespace internal {

complex;

namespace {
// Returns the default Hann window function for the spectrogram.
void GetPeriodicHann(int window_length, std::vector<double>* window) { … }
}  // namespace

bool Spectrogram::Initialize(int window_length, int step_length) { … }

inline int Log2Floor(uint32_t n) { … }

inline int Log2Ceiling(uint32_t n) { … }

inline uint32_t NextPowerOfTwo(uint32_t value) { … }

bool Spectrogram::Initialize(const std::vector<double>& window,
                             int step_length) { … }

template <class InputSample, class OutputSample>
bool Spectrogram::ComputeComplexSpectrogram(
    const std::vector<InputSample>& input,
    std::vector<std::vector<complex<OutputSample>>>* output) { … }
// Instantiate it four ways:
template bool Spectrogram::ComputeComplexSpectrogram(
    const std::vector<float>& input, std::vector<std::vector<complex<float>>>*);
template bool Spectrogram::ComputeComplexSpectrogram(
    const std::vector<double>& input,
    std::vector<std::vector<complex<float>>>*);
template bool Spectrogram::ComputeComplexSpectrogram(
    const std::vector<float>& input,
    std::vector<std::vector<complex<double>>>*);
template bool Spectrogram::ComputeComplexSpectrogram(
    const std::vector<double>& input,
    std::vector<std::vector<complex<double>>>*);

template <class InputSample, class OutputSample>
bool Spectrogram::ComputeSquaredMagnitudeSpectrogram(
    const std::vector<InputSample>& input,
    std::vector<std::vector<OutputSample>>* output) { … }
// Instantiate it four ways:
template bool Spectrogram::ComputeSquaredMagnitudeSpectrogram(
    const std::vector<float>& input, std::vector<std::vector<float>>*);
template bool Spectrogram::ComputeSquaredMagnitudeSpectrogram(
    const std::vector<double>& input, std::vector<std::vector<float>>*);
template bool Spectrogram::ComputeSquaredMagnitudeSpectrogram(
    const std::vector<float>& input, std::vector<std::vector<double>>*);
template bool Spectrogram::ComputeSquaredMagnitudeSpectrogram(
    const std::vector<double>& input, std::vector<std::vector<double>>*);

// Return true if a full window of samples is prepared; manage the queue.
template <class InputSample>
bool Spectrogram::GetNextWindowOfSamples(const std::vector<InputSample>& input,
                                         int* input_start) { … }

void Spectrogram::ProcessCoreFFT() { … }

}  // namespace internal
}  // namespace tflite