online-nnet3-decoding.h

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// online2/online-nnet3-decoding.h

// Copyright 2014  Johns Hopkins University (author: Daniel Povey)
//           2016  Api.ai (Author: Ilya Platonov)

// 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.


#ifndef KALDI_ONLINE2_ONLINE_NNET3_DECODING_H_
#define KALDI_ONLINE2_ONLINE_NNET3_DECODING_H_

#include <string>
#include <vector>
#include <deque>

#include "nnet3/decodable-online-looped.h"
#include "matrix/matrix-lib.h"
#include "util/common-utils.h"
#include "base/kaldi-error.h"
#include "itf/online-feature-itf.h"
#include "online2/online-endpoint.h"
#include "online2/online-nnet2-feature-pipeline.h"
#include "decoder/lattice-faster-online-decoder.h"
#include "hmm/transition-model.h"
#include "hmm/posterior.h"

namespace kaldi {


template <typename FST>
class SingleUtteranceNnet3DecoderTpl {
 public:

  // Constructor. The pointer 'features' is not being given to this class to own
  // and deallocate, it is owned externally.
  SingleUtteranceNnet3DecoderTpl(const LatticeFasterDecoderConfig &decoder_opts,
                                 const TransitionModel &trans_model,
                                 const nnet3::DecodableNnetSimpleLoopedInfo &info,
                                 const FST &fst,
                                 OnlineNnet2FeaturePipeline *features);

  void InitDecoding(int32 frame_offset = 0);

  void AdvanceDecoding();

  void FinalizeDecoding();

  int32 NumFramesDecoded() const;

  void GetLattice(bool end_of_utterance,
                  CompactLattice *clat) const;

  void GetBestPath(bool end_of_utterance,
                   Lattice *best_path) const;


  bool EndpointDetected(const OnlineEndpointConfig &config);

  const LatticeFasterOnlineDecoderTpl<FST> &Decoder() const { return decoder_; }

  ~SingleUtteranceNnet3DecoderTpl() { }
 private:

  const LatticeFasterDecoderConfig &decoder_opts_;

  // this is remembered from the constructor; it's ultimately
  // derived from calling FrameShiftInSeconds() on the feature pipeline.
  BaseFloat input_feature_frame_shift_in_seconds_;

  // we need to keep a reference to the transition model around only because
  // it's needed by the endpointing code.
  const TransitionModel &trans_model_;

  nnet3::DecodableAmNnetLoopedOnline decodable_;

  LatticeFasterOnlineDecoderTpl<FST> decoder_;

};


typedef SingleUtteranceNnet3DecoderTpl<fst::Fst<fst::StdArc> > SingleUtteranceNnet3Decoder;


}  // namespace kaldi



#endif  // KALDI_ONLINE2_ONLINE_NNET3_DECODING_H_