refactor linear feature:unify vector & remove redundant function

pull/1649/head
Yang Zhou 2 years ago
parent e366fb6b2f
commit c11a5d97c2

@ -181,6 +181,10 @@ int main(int argc, char* argv[]) {
ppspeech::LinearSpectrogramOptions opt;
opt.frame_opts.frame_length_ms = 20;
opt.frame_opts.frame_shift_ms = 10;
opt.frame_opts.dither = 0.0;
opt.frame_opts.remove_dc_offset = false;
opt.frame_opts.window_type = "hanning";
opt.frame_opts.preemph_coeff = 0.0;
LOG(INFO) << "frame length (ms): " << opt.frame_opts.frame_length_ms;
LOG(INFO) << "frame shift (ms): " << opt.frame_opts.frame_shift_ms;

@ -14,6 +14,8 @@
#include "frontend/audio/linear_spectrogram.h"
#include "kaldi/base/kaldi-math.h"
#include "kaldi/feat/feature-common.h"
#include "kaldi/feat/feature-functions.h"
#include "kaldi/matrix/matrix-functions.h"
namespace ppspeech {
@ -21,30 +23,23 @@ namespace ppspeech {
using kaldi::int32;
using kaldi::BaseFloat;
using kaldi::Vector;
using kaldi::SubVector;
using kaldi::VectorBase;
using kaldi::Matrix;
using std::vector;
LinearSpectrogram::LinearSpectrogram(
const LinearSpectrogramOptions& opts,
std::unique_ptr<FrontendInterface> base_extractor) {
opts_ = opts;
std::unique_ptr<FrontendInterface> base_extractor)
: opts_(opts), feature_window_funtion_(opts.frame_opts) {
base_extractor_ = std::move(base_extractor);
int32 window_size = opts.frame_opts.WindowSize();
int32 window_shift = opts.frame_opts.WindowShift();
fft_points_ = window_size;
dim_ = window_size / 2 + 1;
chunk_sample_size_ =
static_cast<int32>(opts.streaming_chunk * opts.frame_opts.samp_freq);
hanning_window_.resize(window_size);
double a = M_2PI / (window_size - 1);
hanning_window_energy_ = 0;
for (int i = 0; i < window_size; ++i) {
hanning_window_[i] = 0.5 - 0.5 * cos(a * i);
hanning_window_energy_ += hanning_window_[i] * hanning_window_[i];
}
dim_ = fft_points_ / 2 + 1; // the dimension is Fs/2 Hz
hanning_window_energy_ = kaldi::VecVec(feature_window_funtion_.window,
feature_window_funtion_.window);
}
void LinearSpectrogram::Accept(const VectorBase<BaseFloat>& inputs) {
@ -56,99 +51,57 @@ bool LinearSpectrogram::Read(Vector<BaseFloat>* feats) {
bool flag = base_extractor_->Read(&input_feats);
if (flag == false || input_feats.Dim() == 0) return false;
vector<BaseFloat> input_feats_vec(input_feats.Dim());
std::memcpy(input_feats_vec.data(),
input_feats.Data(),
input_feats.Dim() * sizeof(BaseFloat));
vector<vector<BaseFloat>> result;
Compute(input_feats_vec, result);
int32 feat_size = 0;
if (result.size() != 0) {
feat_size = result.size() * result[0].size();
}
feats->Resize(feat_size);
// todo refactor (SimleGoat)
for (size_t idx = 0; idx < feat_size; ++idx) {
(*feats)(idx) = result[idx / dim_][idx % dim_];
}
return true;
}
void LinearSpectrogram::Hanning(vector<float>* data) const {
CHECK_GE(data->size(), hanning_window_.size());
for (size_t i = 0; i < hanning_window_.size(); ++i) {
data->at(i) *= hanning_window_[i];
}
}
bool LinearSpectrogram::NumpyFft(vector<BaseFloat>* v,
vector<BaseFloat>* real,
vector<BaseFloat>* img) const {
Vector<BaseFloat> v_tmp;
v_tmp.Resize(v->size());
std::memcpy(v_tmp.Data(), v->data(), sizeof(BaseFloat) * (v->size()));
RealFft(&v_tmp, true);
v->resize(v_tmp.Dim());
std::memcpy(v->data(), v_tmp.Data(), sizeof(BaseFloat) * (v->size()));
real->push_back(v->at(0));
img->push_back(0);
for (int i = 1; i < v->size() / 2; i++) {
real->push_back(v->at(2 * i));
img->push_back(v->at(2 * i + 1));
}
real->push_back(v->at(1));
img->push_back(0);
int32 feat_len = input_feats.Dim();
int32 left_len = reminded_wav_.Dim();
Vector<BaseFloat> waves(feat_len + left_len);
waves.Range(0, left_len).CopyFromVec(reminded_wav_);
waves.Range(left_len, feat_len).CopyFromVec(input_feats);
Compute(waves, feats);
int32 frame_shift = opts_.frame_opts.WindowShift();
int32 num_frames = kaldi::NumFrames(waves.Dim(), opts_.frame_opts);
int32 left_samples = waves.Dim() - frame_shift * num_frames;
reminded_wav_.Resize(left_samples);
reminded_wav_.CopyFromVec(
waves.Range(frame_shift * num_frames, left_samples));
return true;
}
// Compute spectrogram feat
// todo: refactor later (SmileGoat)
bool LinearSpectrogram::Compute(const vector<float>& waves,
vector<vector<float>>& feats) {
int num_samples = waves.size();
const int& frame_length = opts_.frame_opts.WindowSize();
const int& sample_rate = opts_.frame_opts.samp_freq;
const int& frame_shift = opts_.frame_opts.WindowShift();
const int& fft_points = fft_points_;
const float scale = hanning_window_energy_ * sample_rate;
bool LinearSpectrogram::Compute(const Vector<BaseFloat>& waves,
Vector<BaseFloat>* feats) {
int32 num_samples = waves.Dim();
int32 frame_length = opts_.frame_opts.WindowSize();
int32 sample_rate = opts_.frame_opts.samp_freq;
BaseFloat scale = 2.0 / (hanning_window_energy_ * sample_rate);
if (num_samples < frame_length) {
return true;
}
int num_frames = 1 + ((num_samples - frame_length) / frame_shift);
feats.resize(num_frames);
vector<float> fft_real((fft_points_ / 2 + 1), 0);
vector<float> fft_img((fft_points_ / 2 + 1), 0);
vector<float> v(frame_length, 0);
vector<float> power((fft_points / 2 + 1));
for (int i = 0; i < num_frames; ++i) {
vector<float> data(waves.data() + i * frame_shift,
waves.data() + i * frame_shift + frame_length);
Hanning(&data);
fft_img.clear();
fft_real.clear();
v.assign(data.begin(), data.end());
NumpyFft(&v, &fft_real, &fft_img);
feats[i].resize(fft_points / 2 + 1); // the last dimension is Fs/2 Hz
for (int j = 0; j < (fft_points / 2 + 1); ++j) {
power[j] = fft_real[j] * fft_real[j] + fft_img[j] * fft_img[j];
feats[i][j] = power[j];
if (j == 0 || j == feats[0].size() - 1) {
feats[i][j] /= scale;
} else {
feats[i][j] *= (2.0 / scale);
}
// log added eps=1e-14
feats[i][j] = std::log(feats[i][j] + 1e-14);
}
int32 num_frames = kaldi::NumFrames(num_samples, opts_.frame_opts);
feats->Resize(num_frames * dim_);
Vector<BaseFloat> window;
for (int frame_idx = 0; frame_idx < num_frames; ++frame_idx) {
kaldi::ExtractWindow(0,
waves,
frame_idx,
opts_.frame_opts,
feature_window_funtion_,
&window,
NULL);
SubVector<BaseFloat> output_row(feats->Data() + frame_idx * dim_, dim_);
window.Resize(frame_length, kaldi::kCopyData);
RealFft(&window, true);
kaldi::ComputePowerSpectrum(&window);
SubVector<BaseFloat> power_spectrum(window, 0, dim_);
power_spectrum.Scale(scale);
power_spectrum(0) = power_spectrum(0) / 2;
power_spectrum(dim_ - 1) = power_spectrum(dim_ - 1) / 2;
power_spectrum.Add(1e-14);
power_spectrum.ApplyLog();
output_row.CopyFromVec(power_spectrum);
}
return true;
}

@ -49,19 +49,15 @@ class LinearSpectrogram : public FrontendInterface {
virtual void Reset() { base_extractor_->Reset(); }
private:
void Hanning(std::vector<kaldi::BaseFloat>* data) const;
bool Compute(const std::vector<kaldi::BaseFloat>& waves,
std::vector<std::vector<kaldi::BaseFloat>>& feats);
bool NumpyFft(std::vector<kaldi::BaseFloat>* v,
std::vector<kaldi::BaseFloat>* real,
std::vector<kaldi::BaseFloat>* img) const;
bool Compute(const kaldi::Vector<kaldi::BaseFloat>& waves,
kaldi::Vector<kaldi::BaseFloat>* feats);
kaldi::int32 fft_points_;
size_t dim_;
std::vector<kaldi::BaseFloat> hanning_window_;
kaldi::FeatureWindowFunction feature_window_funtion_;
kaldi::BaseFloat hanning_window_energy_;
LinearSpectrogramOptions opts_;
std::unique_ptr<FrontendInterface> base_extractor_;
kaldi::Vector<kaldi::BaseFloat> reminded_wav_;
int chunk_sample_size_;
DISALLOW_COPY_AND_ASSIGN(LinearSpectrogram);
};

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