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extend-wav-with-silence.cc
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// online2/extend-wav-with-silence.cc
// 2014 IMSL, PKU-HKUST (author: Wei Shi)
// 2015 Tom Ko
// See ../../COPYING for clarification regarding multiple authors
//
// 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
//
// THIS CODE IS PROVIDED *AS IS* BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, EITHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION ANY IMPLIED
// WARRANTIES OR CONDITIONS OF TITLE, FITNESS FOR A PARTICULAR PURPOSE,
// MERCHANTABLITY OR NON-INFRINGEMENT.
// See the Apache 2 License for the specific language governing permissions and
// limitations under the License.
#include "base/kaldi-common.h"
#include "util/common-utils.h"
#include "feat/wave-reader.h"
namespace kaldi{
void FindQuietestSegment(const Vector<BaseFloat> &wav_in,
BaseFloat samp_rate,
Vector<BaseFloat> *wav_sil,
BaseFloat search_dur = 0.5,
BaseFloat seg_dur = 0.1,
BaseFloat seg_shift_dur = 0.05);
void ExtendWaveWithSilence(const Vector<BaseFloat> &wav_in,
BaseFloat samp_rate,
Vector<BaseFloat> *wav_out,
BaseFloat sil_search_len,
BaseFloat sil_extract_len,
BaseFloat sil_extract_shift);
}
int main(int argc, char *argv[]) {
try {
typedef kaldi::int32 int32;
using namespace kaldi;
const char *usage =
"Extend wave data with a fairly long silence at the end (e.g. 5 seconds).\n"
"The input waveforms are assumed having silences at the begin/end and those\n"
"segments are extracted and appended to the end of the utterance.\n"
"Note this is for use in testing endpointing in decoding.\n"
"\n"
"Usage: extend-wav-with-silence [options] <wav-rspecifier> <wav-wspecifier>\n";
ParseOptions po(usage);
BaseFloat sil_len = 5.0,
sil_search_len = 0.5,
sil_extract_len = 0.05,
sil_extract_shift = 0.025;
po.Register("extra-silence-length", &sil_len, "the length of silence that will be "
"appended to the end of each waveform, in seconds.");
po.Register("silence-search-length", &sil_search_len, "the length at the beginning "
"or end of each waveform in which to search for the quietest segment of "
"silence, in seconds.");
po.Register("silence-extract-length", &sil_extract_len, "the length of silence segments "
"to be extracted from the waveform, which must be smaller than silence-"
"search-length, in seconds.");
po.Register("silence-extract-shift", &sil_extract_shift, "the shift length when searching "
"for segments of silences, typically samller than silence-extract-length, "
"in seconds.");
po.Read(argc, argv);
if (po.NumArgs() != 2) {
po.PrintUsage();
exit(1);
}
std::string wav_rspecifier = po.GetArg(1);
std::string wav_wspecifier = po.GetArg(2);
SequentialTableReader<WaveHolder> reader(wav_rspecifier);
TableWriter<WaveHolder> writer(wav_wspecifier);
int32 num_success = 0;
for(; !reader.Done(); reader.Next()){
std::string wav_key = reader.Key();
const WaveData &wave = reader.Value();
BaseFloat samp_freq = wave.SampFreq(); // read sampling fequency
const Matrix<BaseFloat> &wave_data = wave.Data();
int32 num_chan = wave_data.NumRows(), // number of channels in recording
num_ext_samp = (int32)(samp_freq * sil_len); // number of samples that will be extended
KALDI_ASSERT(num_ext_samp > 0);
Matrix<BaseFloat> new_wave(wave_data.NumRows(), wave_data.NumCols() + num_ext_samp);
for(int32 i = 0; i < num_chan; i++){
Vector<BaseFloat> wav_this_chan(wave_data.Row(i));
Vector<BaseFloat> wav_extend(wav_this_chan.Dim() + num_ext_samp);
ExtendWaveWithSilence(wav_this_chan, samp_freq, &wav_extend,
sil_search_len, sil_extract_len, sil_extract_shift);
KALDI_ASSERT(wav_extend.Dim() == wav_this_chan.Dim() + num_ext_samp);
new_wave.CopyRowFromVec(wav_extend, i);
}
WaveData wave_out(samp_freq, new_wave);
writer.Write(wav_key, wave_out);
num_success++;
}
KALDI_LOG << "Successfully extended " << num_success << " files.";
return 0;
} catch(const std::exception &e) {
std::cerr << e.what();
return -1;
}
}
namespace kaldi{
void ExtendWaveWithSilence(const Vector<BaseFloat> &wav_in,
BaseFloat samp_rate,
Vector<BaseFloat> *wav_out,
BaseFloat sil_search_len,
BaseFloat sil_extract_len,
BaseFloat sil_extract_shift){
Vector<BaseFloat> quietest_seg;
FindQuietestSegment(wav_in, samp_rate, &quietest_seg,
sil_search_len, sil_extract_len, sil_extract_shift);
int32 window_size = quietest_seg.Dim(),
window_size_half = window_size / 2;
KALDI_ASSERT(window_size > 0);
Vector<BaseFloat> window(window_size);
Vector<BaseFloat> windowed_silence(window_size);
Vector<BaseFloat> half_window(window_size_half);
for(int32 i = 0; i < window.Dim(); i++){
BaseFloat i_fl = static_cast<BaseFloat>(i);
window(i) = 0.54 - 0.46*cos(M_2PI * i_fl / (window_size-1));
}
half_window = window.Range(window_size_half, window_size_half);
windowed_silence.AddVecVec(1.0, window, quietest_seg, 0.0);
wav_out->Range(0, wav_in.Dim()).CopyFromVec(wav_in);
SubVector<BaseFloat> wav_ext(*wav_out, wav_in.Dim() - window_size_half,
wav_out->Dim() - wav_in.Dim() + window_size_half);
for(int32 i = 0; i < window_size_half; i++) // windowing the first half window
wav_ext(i) *= half_window(i);
int32 tmp_offset = 0;
for(; tmp_offset + window_size < wav_ext.Dim();) {
wav_ext.Range(tmp_offset, window_size).AddVec(1.0, windowed_silence);
tmp_offset += window_size_half;
}
for(int32 i = tmp_offset; i < wav_ext.Dim(); i++)
wav_ext(i) += windowed_silence(i-tmp_offset);
}
// Try to find the quietest seq_dur(default 0.1) second segment in the
// search_dur(default 0.5) seconds at the beginning and the end
// of input waveform by simply find a segment with the least energy.
void FindQuietestSegment(const Vector<BaseFloat> &wav_in,
BaseFloat samp_rate,
Vector<BaseFloat> *wav_sil,
BaseFloat search_dur,
BaseFloat seg_dur,
BaseFloat seg_shift_dur){
KALDI_ASSERT(seg_dur < search_dur);
int32 search_len = (int32) (search_dur * samp_rate),
seg_len = (int32) (seg_dur * samp_rate),
seg_shift = (int32) (seg_shift_dur *samp_rate),
start = 0;
double min_energy;
Vector<BaseFloat> wav_min_energy;
Vector<BaseFloat> seg_tmp(wav_in.Range(0, seg_len));
wav_min_energy = seg_tmp;
min_energy = VecVec(seg_tmp, seg_tmp);
for(start = 0; start + seg_len < search_len; ){
SubVector<BaseFloat> seg_this(wav_in, start, seg_len);
seg_tmp = seg_this;
double energy_this = VecVec(seg_this, seg_this);
if(energy_this < min_energy && energy_this > 0.0){
min_energy = energy_this;
wav_min_energy = seg_tmp;
}
start += seg_shift;
}
for(start = wav_in.Dim() - search_len; start + seg_len < wav_in.Dim(); ){
SubVector<BaseFloat> seg_this(wav_in, start, seg_len);
seg_tmp = seg_this;
double energy_this = VecVec(seg_this, seg_this);
if(energy_this < min_energy && energy_this > 0.0){
min_energy = energy_this;
wav_min_energy = seg_tmp;
}
start += seg_shift;
}
if (min_energy == 0.0) {
KALDI_WARN << "Zero energy silence being used.";
}
*wav_sil = wav_min_energy;
}
}