extract-feature-segments.cc File Reference

#include "base/kaldi-common.h"
#include "util/common-utils.h"
#include "feat/feature-mfcc.h"
#include "matrix/kaldi-matrix.h"

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Functions
int	main (int argc, char *argv[])
	This is a program for extracting segments from feature files/archives. More...

Function Documentation

main()

int main	(	int	argc,
		char *	argv[]
	)

This is a program for extracting segments from feature files/archives.

• usage :
  • extract-feature-segments [options ..] <scriptfile/archive> <segments-file> <features-written-specifier>
  • "segments-file" should have the information of the segments that needs to be extracted from the feature files
  • the format of the segments file : speaker_name filename start_time(in secs) end_time(in secs)
  • "features-written-specifier" is the output segment format

Definition at line 34 of file extract-feature-segments.cc.

References kaldi::ConvertStringToInteger(), kaldi::ConvertStringToReal(), ParseOptions::GetArg(), RandomAccessTableReader< Holder >::HasKey(), KALDI_LOG, KALDI_WARN, ParseOptions::NumArgs(), MatrixBase< Real >::NumCols(), MatrixBase< Real >::NumRows(), ParseOptions::PrintUsage(), ParseOptions::Read(), ParseOptions::Register(), kaldi::SplitStringToVector(), Input::Stream(), RandomAccessTableReader< Holder >::Value(), and TableWriter< Holder >::Write().

                                 {
  try {
    using namespace kaldi;

    const char *usage =
        "Create feature files by segmenting input files.\n"
        "Note: this program should no longer be needed now that\n"
        "'ranges' in scp files are supported; search for 'ranges' in\n"
        "http://kaldi-asr.org/doc/io_tut.html, or see the script\n"
        "utils/data/subsegment_data_dir.sh.\n"
        "Usage:  "
        "extract-feature-segments [options...] <feats-rspecifier> "
        " <segments-file> <feats-wspecifier>\n"
        " (segments-file has lines like: "
        "output-utterance-id input-utterance-or-spk-id 1.10 2.36)\n";

    // construct all the global objects
    ParseOptions po(usage);

    BaseFloat min_segment_length = 0.1,  // Minimum segment length in seconds.
        max_overshoot = 0.0;  // max time by which last segment can overshoot
    int32 frame_shift = 10;
    int32 frame_length = 25;
    bool snip_edges = true;

    // Register the options
    po.Register("min-segment-length", &min_segment_length,
        "Minimum segment length in seconds (reject shorter segments)");
    po.Register("frame-length", &frame_length, "Frame length in milliseconds");
    po.Register("frame-shift", &frame_shift, "Frame shift in milliseconds");
    po.Register("max-overshoot", &max_overshoot,
        "End segments overshooting by less (in seconds) are truncated,"
        " else rejected.");
    po.Register("snip-edges", &snip_edges,
        "If true, n_frames frames will be snipped from the end of each "
        "extracted feature matrix, "
        "where n_frames = ceil((frame_length - frame_shift) / frame_shift), "
        "This ensures that only the feature vectors that "
        "completely fit in the segment are extracted. "
        "This makes the extracted segment lengths match the lengths of the "
        "features that have been extracted from already segmented audio.");

    // OPTION PARSING ...
    // parse options  (+filling the registered variables)
    po.Read(argc, argv);
    // number of arguments should be 3
    // (scriptfile, segments file and outputwav write mode)
    if (po.NumArgs() != 3) {
      po.PrintUsage();
      exit(1);
    }

    std::string rspecifier = po.GetArg(1);  // get script file/feature archive
    std::string segments_rxfilename = po.GetArg(2);  // get segment file
    std::string wspecifier = po.GetArg(3);  // get written archive name

    BaseFloatMatrixWriter feat_writer(wspecifier);

    RandomAccessBaseFloatMatrixReader feat_reader(rspecifier);

    Input ki(segments_rxfilename);  // no binary argment: never binary.

    int32 num_lines = 0, num_success = 0;

    int32 snip_length = 0;
    if (snip_edges) {
      snip_length = static_cast<int32>(ceil(
          1.0 * (frame_length - frame_shift) / frame_shift));
    }

    std::string line;
    /* read each line from segments file */
    while (std::getline(ki.Stream(), line)) {
      num_lines++;
      std::vector<std::string> split_line;
      // Split the line by space or tab and check the number of fields in each
      // line. There must be 4 fields--segment name , reacording wav file name,
      // start time, end time; 5th field (channel info) is optional.
      SplitStringToVector(line, " \t\r", true, &split_line);
      if (split_line.size() != 4 && split_line.size() != 5) {
        KALDI_WARN << "Invalid line in segments file: " << line;
        continue;
      }
      std::string segment = split_line[0],
          utterance = split_line[1],
          start_str = split_line[2],
          end_str = split_line[3];

      // Convert the start time and endtime to real from string. Segment is
      // ignored if start or end time cannot be converted to real.
      double start, end;
      if (!ConvertStringToReal(start_str, &start)) {
        KALDI_WARN << "Invalid line in segments file [bad start]: " << line;
        continue;
      }
      if (!ConvertStringToReal(end_str, &end)) {
        KALDI_WARN << "Invalid line in segments file [bad end]: " << line;
        continue;
      }

      // start time must not be negative; start time must not be greater than
      // end time, except if end time is -1
      if (start < 0 || end <= 0 || start >= end) {
        KALDI_WARN << "Invalid line in segments file "
            "[empty or invalid segment]: "
                   << line;
        continue;
      }
      int32 channel = -1;  // means channel info is unspecified.
      // if each line has 5 elements then 5th element must be channel identifier
      if (split_line.size() == 5) {
        if (!ConvertStringToInteger(split_line[4], &channel) || channel < 0) {
          KALDI_WARN<< "Invalid line in segments file [bad channel]: " << line;
          continue;
        }
      }

      /* check whether a segment start time and end time exists in utterance
       * if fails , skips the segment.
       */
      if (!feat_reader.HasKey(utterance)) {
        KALDI_WARN << "Did not find features for utterance " << utterance
                   << ", skipping segment " << segment;
        continue;
      }
      const Matrix<BaseFloat> &feats = feat_reader.Value(utterance);
      // total number of samples present in wav data
      int32 num_samp = feats.NumRows();
      // total number of channels present in wav file
      int32 num_chan = feats.NumCols();
      // Convert start & end times of the segment to corresponding sample number
      int32 start_samp = static_cast<int32>(round(
          (start * 1000.0 / frame_shift)));
      int32 end_samp = static_cast<int32>(round(end * 1000.0 / frame_shift));

      if (snip_edges) {
        // snip the edge at the end of the segment (usually 2 frames),
        end_samp -= snip_length;
      }

      /* start sample must be less than total number of samples
       * otherwise skip the segment
       */
      if (start_samp < 0 || start_samp >= num_samp) {
        KALDI_WARN << "Start sample out of range " << start_samp
            << " [length:] " << num_samp << "x" << num_chan
            << ", skipping segment " << segment;
        continue;
      }

      /* end sample must be less than total number samples
       * otherwise skip the segment
       */
      if (end_samp > num_samp) {
        if (end_samp >= num_samp
                + static_cast<int32>(
                    round(max_overshoot * 1000.0 / frame_shift))) {
          KALDI_WARN<< "End sample too far out of range " << end_samp
              << " [length:] " << num_samp << "x" << num_chan
              << ", skipping segment "
              << segment;
          continue;
        }
        end_samp = num_samp;  // for small differences, just truncate.
      }

      /* check whether the segment size is less than minimum segment length(default 0.1 sec)
       * if yes, skip the segment
       */
      if (end_samp
          <= start_samp
              + static_cast<int32>(round(
                  (min_segment_length * 1000.0 / frame_shift)))) {
        KALDI_WARN<< "Segment " << segment << " too short, skipping it.";
        continue;
      }

      SubMatrix<BaseFloat> segment_matrix(feats, start_samp,
          end_samp-start_samp, 0, num_chan);
      Matrix<BaseFloat> outmatrix(segment_matrix);
      // write segment in feature archive.
      feat_writer.Write(segment, outmatrix);
      num_success++;
    }
    KALDI_LOG << "Successfully processed " << num_success << " lines out of "
              << num_lines << " in the segments file. ";
    /* prints number of segments processed */
    if (num_success == 0) return -1;
    return 0;
  } catch(const std::exception &e) {
    std::cerr << e.what();
    return -1;
  }
}