OnlineSilenceWeighting Class Reference

#include <online-ivector-feature.h>

Collaboration diagram for OnlineSilenceWeighting:

Classes
struct	FrameInfo

Public Member Functions
	OnlineSilenceWeighting (const TransitionModel &trans_model, const OnlineSilenceWeightingConfig &config, int32 frame_subsampling_factor=1)
bool	Active () const
template<typename FST >
void	ComputeCurrentTraceback (const LatticeFasterOnlineDecoderTpl< FST > &decoder)
template<typename FST >
void	ComputeCurrentTraceback (const LatticeIncrementalOnlineDecoderTpl< FST > &decoder)
void	GetDeltaWeights (int32 num_frames_ready, int32 first_decoder_frame, std::vector< std::pair< int32, BaseFloat > > *delta_weights)
void	GetDeltaWeights (int32 num_frames_ready, std::vector< std::pair< int32, BaseFloat > > *delta_weights)

Private Attributes
const TransitionModel &	trans_model_
const OnlineSilenceWeightingConfig &	config_
int32	frame_subsampling_factor_
unordered_set< int32 >	silence_phones_
std::vector< FrameInfo >	frame_info_
int32	num_frames_output_and_correct_

Detailed Description

Definition at line 465 of file online-ivector-feature.h.

Constructor & Destructor Documentation

OnlineSilenceWeighting()

OnlineSilenceWeighting	(	const TransitionModel &	trans_model,
		const OnlineSilenceWeightingConfig &	config,
		int32	frame_subsampling_factor = 1
	)

Definition at line 465 of file online-ivector-feature.cc.

References OnlineSilenceWeighting::frame_subsampling_factor_, rnnlm::i, KALDI_ASSERT, OnlineSilenceWeighting::silence_phones_, OnlineSilenceWeightingConfig::silence_phones_str, and kaldi::SplitStringToIntegers().

                                   :
    trans_model_(trans_model), config_(config),
    frame_subsampling_factor_(frame_subsampling_factor),
    num_frames_output_and_correct_(0) {
  KALDI_ASSERT(frame_subsampling_factor_ >= 1);
  std::vector<int32> silence_phones;
  SplitStringToIntegers(config.silence_phones_str, ":,", false,
                        &silence_phones);
  for (size_t i = 0; i < silence_phones.size(); i++)
    silence_phones_.insert(silence_phones[i]);
}

Member Function Documentation

Active()

bool Active ( ) const

inline

Definition at line 478 of file online-ivector-feature.h.

Referenced by main(), SingleUtteranceNnet2DecoderThreaded::RunDecoderSearchInternal(), and SingleUtteranceNnet2DecoderThreaded::RunNnetEvaluationInternal().

{ return config_.Active(); }

ComputeCurrentTraceback() [1/2]

void ComputeCurrentTraceback

(

const LatticeFasterOnlineDecoderTpl< FST > &

decoder

)

Definition at line 482 of file online-ivector-feature.cc.

References LatticeFasterOnlineDecoderTpl< FST >::BestPathEnd(), LatticeFasterOnlineDecoderTpl< FST >::BestPathIterator::frame, OnlineSilenceWeighting::frame_info_, KALDI_ASSERT, KALDI_ERR, OnlineSilenceWeighting::num_frames_output_and_correct_, LatticeFasterDecoderTpl< FST, decoder::BackpointerToken >::NumFramesDecoded(), LatticeFasterOnlineDecoderTpl< FST >::BestPathIterator::tok, and LatticeFasterOnlineDecoderTpl< FST >::TraceBackBestPath().

Referenced by main(), and SingleUtteranceNnet2DecoderThreaded::RunDecoderSearchInternal().

                                                       {
  int32 num_frames_decoded = decoder.NumFramesDecoded(),
      num_frames_prev = frame_info_.size();
  // note, num_frames_prev is not the number of frames previously decoded,
  // it's the generally-larger number of frames that we were requested to
  // provide weights for.
  if (num_frames_prev < num_frames_decoded)
    frame_info_.resize(num_frames_decoded);
  if (num_frames_prev > num_frames_decoded &&
      frame_info_[num_frames_decoded].transition_id != -1)
    KALDI_ERR << "Number of frames decoded decreased";  // Likely bug

  if (num_frames_decoded == 0)
    return;
  int32 frame = num_frames_decoded - 1;
  bool use_final_probs = false;
  typename LatticeFasterOnlineDecoderTpl<FST>::BestPathIterator iter =
      decoder.BestPathEnd(use_final_probs, NULL);
  while (frame >= 0) {
    LatticeArc arc;
    arc.ilabel = 0;
    while (arc.ilabel == 0)  // the while loop skips over input-epsilons
      iter = decoder.TraceBackBestPath(iter, &arc);
    // note, the iter.frame values are slightly unintuitively defined,
    // they are one less than you might expect.
    KALDI_ASSERT(iter.frame == frame - 1);

    if (frame_info_[frame].token == iter.tok) {
      // we know that the traceback from this point back will be identical, so
      // no point tracing back further.  Note: we are comparing memory addresses
      // of tokens of the decoder; this guarantees it's the same exact token
      // because tokens, once allocated on a frame, are only deleted, never
      // reallocated for that frame.
      break;
    }

    if (num_frames_output_and_correct_ > frame)
      num_frames_output_and_correct_ = frame;

    frame_info_[frame].token = iter.tok;
    frame_info_[frame].transition_id = arc.ilabel;
    frame--;
    // leave frame_info_.current_weight at zero for now (as set in the
    // constructor), reflecting that we haven't already output a weight for that
    // frame.
  }
}

ComputeCurrentTraceback() [2/2]

void ComputeCurrentTraceback

(

const LatticeIncrementalOnlineDecoderTpl< FST > &

decoder

)

Definition at line 532 of file online-ivector-feature.cc.

References LatticeIncrementalOnlineDecoderTpl< FST >::BestPathEnd(), LatticeIncrementalOnlineDecoderTpl< FST >::BestPathIterator::frame, OnlineSilenceWeighting::frame_info_, KALDI_ASSERT, KALDI_ERR, OnlineSilenceWeighting::num_frames_output_and_correct_, LatticeIncrementalDecoderTpl< FST, decoder::BackpointerToken >::NumFramesDecoded(), LatticeIncrementalOnlineDecoderTpl< FST >::BestPathIterator::tok, and LatticeIncrementalOnlineDecoderTpl< FST >::TraceBackBestPath().

                                                            {
  int32 num_frames_decoded = decoder.NumFramesDecoded(),
      num_frames_prev = frame_info_.size();
  // note, num_frames_prev is not the number of frames previously decoded,
  // it's the generally-larger number of frames that we were requested to
  // provide weights for.
  if (num_frames_prev < num_frames_decoded)
    frame_info_.resize(num_frames_decoded);
  if (num_frames_prev > num_frames_decoded &&
      frame_info_[num_frames_decoded].transition_id != -1)
    KALDI_ERR << "Number of frames decoded decreased";  // Likely bug

  if (num_frames_decoded == 0)
    return;
  int32 frame = num_frames_decoded - 1;
  bool use_final_probs = false;
  typename LatticeIncrementalOnlineDecoderTpl<FST>::BestPathIterator iter =
      decoder.BestPathEnd(use_final_probs, NULL);
  while (frame >= 0) {
    LatticeArc arc;
    arc.ilabel = 0;
    while (arc.ilabel == 0)  // the while loop skips over input-epsilons
      iter = decoder.TraceBackBestPath(iter, &arc);
    // note, the iter.frame values are slightly unintuitively defined,
    // they are one less than you might expect.
    KALDI_ASSERT(iter.frame == frame - 1);

    if (frame_info_[frame].token == iter.tok) {
      // we know that the traceback from this point back will be identical, so
      // no point tracing back further.  Note: we are comparing memory addresses
      // of tokens of the decoder; this guarantees it's the same exact token,
      // because tokens, once allocated on a frame, are only deleted, never
      // reallocated for that frame.
      break;
    }

    if (num_frames_output_and_correct_ > frame)
      num_frames_output_and_correct_ = frame;

    frame_info_[frame].token = iter.tok;
    frame_info_[frame].transition_id = arc.ilabel;
    frame--;
    // leave frame_info_.current_weight at zero for now (as set in the
    // constructor), reflecting that we haven't already output a weight for that
    // frame.
  }
}

GetDeltaWeights() [1/2]

void GetDeltaWeights	(	int32	num_frames_ready,
		int32	first_decoder_frame,
		std::vector< std::pair< int32, BaseFloat > > *	delta_weights
	)

Definition at line 597 of file online-ivector-feature.cc.

References OnlineSilenceWeighting::config_, OnlineSilenceWeighting::frame_info_, OnlineSilenceWeighting::frame_subsampling_factor_, rnnlm::i, KALDI_ASSERT, KALDI_VLOG, OnlineSilenceWeightingConfig::max_state_duration, OnlineSilenceWeighting::silence_phones_, OnlineSilenceWeightingConfig::silence_weight, OnlineSilenceWeighting::trans_model_, and TransitionModel::TransitionIdToPhone().

Referenced by main(), and SingleUtteranceNnet2DecoderThreaded::RunNnetEvaluationInternal().

                                                          {
  // num_frames_ready is at the feature frame-rate, most of the code
  // in this function is at the decoder frame-rate.
  // round up, so we are sure to get weights for at least the frame
  // 'num_frames_ready - 1', and maybe one or two frames afterward.
  KALDI_ASSERT(num_frames_ready > first_decoder_frame || num_frames_ready == 0);
  int32 fs = frame_subsampling_factor_,
  num_decoder_frames_ready = (num_frames_ready - first_decoder_frame + fs - 1) / fs;

  const int32 max_state_duration = config_.max_state_duration;
  const BaseFloat silence_weight = config_.silence_weight;

  delta_weights->clear();

  int32 prev_num_frames_processed = frame_info_.size();
  if (frame_info_.size() < static_cast<size_t>(num_decoder_frames_ready))
    frame_info_.resize(num_decoder_frames_ready);

  // Don't go further backward into the past then 100 frames before the most
  // recent frame previously than 100 frames when modifying the traceback.
  // C.f. the value 200 in template
  // OnlineGenericBaseFeature<C>::OnlineGenericBaseFeature in online-feature.cc,
  // which needs to be more than this value of 100 plus the amount of context
  // that LDA might use plus the chunk size we're likely to decode in one time.
  // The user can always increase the value of --max-feature-vectors in case one
  // of these conditions is broken.  Search for ONLINE_IVECTOR_LIMIT in
  // online-feature.cc
  int32 begin_frame = std::max<int32>(0, prev_num_frames_processed - 100),
      frames_out = static_cast<int32>(frame_info_.size()) - begin_frame;
  // frames_out is the number of frames we will output.
  KALDI_ASSERT(frames_out >= 0);
  std::vector<BaseFloat> frame_weight(frames_out, 1.0);
  // we will set frame_weight to the value silence_weight for silence frames and
  // for transition-ids that repeat with duration > max_state_duration.  Frames
  // newer than the most recent traceback will get a weight equal to the weight
  // for the most recent frame in the traceback; or the silence weight, if there
  // is no traceback at all available yet.

  // First treat some special cases.
  if (frames_out == 0)  // Nothing to output.
    return;
  if (frame_info_[begin_frame].transition_id == -1) {
    // We do not have any traceback at all within the frames we are to output...
    // find the most recent weight that we output and apply the same weight to
    // all the new output; or output the silence weight, if nothing was output.
    BaseFloat weight = (begin_frame == 0 ? silence_weight :
                        frame_info_[begin_frame - 1].current_weight);
    for (int32 offset = 0; offset < frames_out; offset++)
      frame_weight[offset] = weight;
  } else {
    int32 current_run_start_offset = 0;
    for (int32 offset = 0; offset < frames_out; offset++) {
      int32 frame = begin_frame + offset;
      int32 transition_id = frame_info_[frame].transition_id;
      if (transition_id == -1) {
        // this frame does not yet have a decoder traceback, so just
        // duplicate the silence/non-silence status of the most recent
        // frame we have a traceback for (probably a reasonable guess).
        frame_weight[offset] = frame_weight[offset - 1];
      } else {
        int32 phone = trans_model_.TransitionIdToPhone(transition_id);
        bool is_silence = (silence_phones_.count(phone) != 0);
        if (is_silence)
          frame_weight[offset] = silence_weight;
        // now deal with max-duration issues.
        if (max_state_duration > 0 &&
            (offset + 1 == frames_out ||
             transition_id != frame_info_[frame + 1].transition_id)) {
          // If this is the last frame of a run...
          int32 run_length = offset - current_run_start_offset + 1;
          if (run_length >= max_state_duration) {
            // treat runs of the same transition-id longer than the max, as
            // silence, even if they were not silence.
            for (int32 offset2 = current_run_start_offset;
                 offset2 <= offset; offset2++)
              frame_weight[offset2] = silence_weight;
          }
          if (offset + 1 < frames_out)
            current_run_start_offset = offset + 1;
        }
      }
    }
  }
  // Now commit the stats...
  for (int32 offset = 0; offset < frames_out; offset++) {
    int32 frame = begin_frame + offset;
    BaseFloat old_weight = frame_info_[frame].current_weight,
        new_weight = frame_weight[offset],
        weight_diff = new_weight - old_weight;
    frame_info_[frame].current_weight = new_weight;
    // Even if the delta-weight is zero for the last frame, we provide it,
    // because the identity of the most recent frame with a weight is used in
    // some debugging/checking code.
    if (weight_diff != 0.0 || offset + 1 == frames_out) {
      KALDI_VLOG(6) << "Weight for frame " << frame << " changing from "
                    << old_weight << " to " << new_weight;
      for(int32 i = 0; i < frame_subsampling_factor_; i++) {
        int32 input_frame = first_decoder_frame + (frame * frame_subsampling_factor_) + i;
        delta_weights->push_back(std::make_pair(input_frame, weight_diff));
      }
    }
  }
}

GetDeltaWeights() [2/2]

void GetDeltaWeights ( int32  num_frames_ready, std::vector< std::pair< int32, BaseFloat > > *  delta_weights  )

inline

Definition at line 519 of file online-ivector-feature.h.

                                                            {
    GetDeltaWeights(num_frames_ready, 0, delta_weights);
  }

Member Data Documentation

config_

const OnlineSilenceWeightingConfig& config_

private

Definition at line 527 of file online-ivector-feature.h.

Referenced by OnlineSilenceWeighting::GetDeltaWeights().

frame_info_

std::vector<FrameInfo> frame_info_

private

Definition at line 551 of file online-ivector-feature.h.

Referenced by OnlineSilenceWeighting::ComputeCurrentTraceback(), and OnlineSilenceWeighting::GetDeltaWeights().

frame_subsampling_factor_

int32 frame_subsampling_factor_

private

Definition at line 529 of file online-ivector-feature.h.

Referenced by OnlineSilenceWeighting::GetDeltaWeights(), and OnlineSilenceWeighting::OnlineSilenceWeighting().

num_frames_output_and_correct_

int32 num_frames_output_and_correct_

private

Definition at line 561 of file online-ivector-feature.h.

Referenced by OnlineSilenceWeighting::ComputeCurrentTraceback().

silence_phones_

unordered_set<int32> silence_phones_

private

Definition at line 531 of file online-ivector-feature.h.

Referenced by OnlineSilenceWeighting::GetDeltaWeights(), and OnlineSilenceWeighting::OnlineSilenceWeighting().

trans_model_

const TransitionModel& trans_model_

private

Definition at line 526 of file online-ivector-feature.h.

Referenced by OnlineSilenceWeighting::GetDeltaWeights().

---

The documentation for this class was generated from the following files:

• online2/online-ivector-feature.h
• online2/online-ivector-feature.cc