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#include "online-feature.h"
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#include <utility>
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OnlineFeature::OnlineFeature(int sample_rate, knf::FbankOptions fbank_opts, int lfr_m, int lfr_n,
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std::vector<std::vector<float>> cmvns)
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: sample_rate_(sample_rate),
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fbank_opts_(std::move(fbank_opts)),
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lfr_m_(lfr_m),
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lfr_n_(lfr_n),
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cmvns_(std::move(cmvns)) {
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frame_sample_length_ = sample_rate_ / 1000 * 25;;
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frame_shift_sample_length_ = sample_rate_ / 1000 * 10;
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}
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void OnlineFeature::extractFeats(vector<std::vector<float>> &vad_feats,
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vector<float> waves, bool input_finished) {
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input_finished_ = input_finished;
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onlineFbank(vad_feats, waves);
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// cache deal & online lfr,cmvn
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if (vad_feats.size() > 0) {
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if (!reserve_waveforms_.empty()) {
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waves.insert(waves.begin(), reserve_waveforms_.begin(), reserve_waveforms_.end());
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}
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if (lfr_splice_cache_.empty()) {
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for (int i = 0; i < (lfr_m_ - 1) / 2; i++) {
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lfr_splice_cache_.emplace_back(vad_feats[0]);
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}
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}
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if (vad_feats.size() + lfr_splice_cache_.size() >= lfr_m_) {
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vad_feats.insert(vad_feats.begin(), lfr_splice_cache_.begin(), lfr_splice_cache_.end());
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int frame_from_waves = (waves.size() - frame_sample_length_) / frame_shift_sample_length_ + 1;
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int minus_frame = reserve_waveforms_.empty() ? (lfr_m_ - 1) / 2 : 0;
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int lfr_splice_frame_idxs = OnlineLfrCmvn(vad_feats);
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int reserve_frame_idx = lfr_splice_frame_idxs - minus_frame;
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reserve_waveforms_.clear();
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reserve_waveforms_.insert(reserve_waveforms_.begin(),
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waves.begin() + reserve_frame_idx * frame_shift_sample_length_,
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waves.begin() + frame_from_waves * frame_shift_sample_length_);
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int sample_length = (frame_from_waves - 1) * frame_shift_sample_length_ + frame_sample_length_;
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waves.erase(waves.begin() + sample_length, waves.end());
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} else {
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reserve_waveforms_.clear();
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reserve_waveforms_.insert(reserve_waveforms_.begin(),
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waves.begin() + frame_sample_length_ - frame_shift_sample_length_, waves.end());
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lfr_splice_cache_.insert(lfr_splice_cache_.end(), vad_feats.begin(), vad_feats.end());
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}
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} else {
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if (input_finished_) {
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if (!reserve_waveforms_.empty()) {
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waves = reserve_waveforms_;
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}
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vad_feats = lfr_splice_cache_;
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OnlineLfrCmvn(vad_feats);
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reset_cache();
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}
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}
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}
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int OnlineFeature::OnlineLfrCmvn(vector<vector<float>> &vad_feats) {
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vector<vector<float>> out_feats;
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int T = vad_feats.size();
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int T_lrf = ceil((T - (lfr_m_ - 1) / 2) / lfr_n_);
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int lfr_splice_frame_idxs = T_lrf;
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vector<float> p;
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for (int i = 0; i < T_lrf; i++) {
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if (lfr_m_ <= T - i * lfr_n_) {
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for (int j = 0; j < lfr_m_; j++) {
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p.insert(p.end(), vad_feats[i * lfr_n_ + j].begin(), vad_feats[i * lfr_n_ + j].end());
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}
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out_feats.emplace_back(p);
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p.clear();
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} else {
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if (input_finished_) {
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int num_padding = lfr_m_ - (T - i * lfr_n_);
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for (int j = 0; j < (vad_feats.size() - i * lfr_n_); j++) {
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p.insert(p.end(), vad_feats[i * lfr_n_ + j].begin(), vad_feats[i * lfr_n_ + j].end());
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}
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for (int j = 0; j < num_padding; j++) {
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p.insert(p.end(), vad_feats[vad_feats.size() - 1].begin(), vad_feats[vad_feats.size() - 1].end());
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}
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out_feats.emplace_back(p);
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} else {
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lfr_splice_frame_idxs = i;
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break;
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}
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}
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}
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lfr_splice_frame_idxs = std::min(T - 1, lfr_splice_frame_idxs * lfr_n_);
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lfr_splice_cache_.clear();
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lfr_splice_cache_.insert(lfr_splice_cache_.begin(), vad_feats.begin() + lfr_splice_frame_idxs, vad_feats.end());
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// Apply cmvn
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for (auto &out_feat: out_feats) {
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for (int j = 0; j < cmvns_[0].size(); j++) {
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out_feat[j] = (out_feat[j] + cmvns_[0][j]) * cmvns_[1][j];
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}
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}
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vad_feats = out_feats;
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return lfr_splice_frame_idxs;
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}
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void OnlineFeature::onlineFbank(vector<std::vector<float>> &vad_feats,
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vector<float> &waves) {
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knf::OnlineFbank fbank(fbank_opts_);
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// cache merge
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waves.insert(waves.begin(), input_cache_.begin(), input_cache_.end());
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int frame_number = compute_frame_num(waves.size(), frame_sample_length_, frame_shift_sample_length_);
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// Send the audio after the last frame shift position to the cache
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input_cache_.clear();
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input_cache_.insert(input_cache_.begin(), waves.begin() + frame_number * frame_shift_sample_length_, waves.end());
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if (frame_number == 0) {
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return;
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}
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// Delete audio that haven't undergone fbank processing
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waves.erase(waves.begin() + (frame_number - 1) * frame_shift_sample_length_ + frame_sample_length_, waves.end());
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fbank.AcceptWaveform(sample_rate_, &waves[0], waves.size());
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int32_t frames = fbank.NumFramesReady();
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for (int32_t i = 0; i != frames; ++i) {
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const float *frame = fbank.GetFrame(i);
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vector<float> frame_vector(frame, frame + fbank_opts_.mel_opts.num_bins);
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vad_feats.emplace_back(frame_vector);
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}
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}
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