online-feature-itf.h

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// itf/online-feature-itf.h

// Copyright    2013  Johns Hopkins University (author: Daniel Povey)

// 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_ITF_ONLINE_FEATURE_ITF_H_
#define KALDI_ITF_ONLINE_FEATURE_ITF_H_ 1
#include "base/kaldi-common.h"
#include "matrix/matrix-lib.h"

namespace kaldi {

class OnlineFeatureInterface {
 public:
  virtual int32 Dim() const = 0; 

  virtual int32 NumFramesReady() const = 0;

  virtual bool IsLastFrame(int32 frame) const = 0;

  virtual void GetFrame(int32 frame, VectorBase<BaseFloat> *feat) = 0;


  virtual void GetFrames(const std::vector<int32> &frames,
                         MatrixBase<BaseFloat> *feats) {
    KALDI_ASSERT(static_cast<int32>(frames.size()) == feats->NumRows());
    for (size_t i = 0; i < frames.size(); i++) {
      SubVector<BaseFloat> feat(*feats, i);
      GetFrame(frames[i], &feat);
    }
  }


  // Returns frame shift in seconds.  Helps to estimate duration from frame
  // counts.
  virtual BaseFloat FrameShiftInSeconds() const = 0;

  virtual ~OnlineFeatureInterface() { }

};


class OnlineBaseFeature: public OnlineFeatureInterface {
 public:
  virtual void AcceptWaveform(BaseFloat sampling_rate,
                              const VectorBase<BaseFloat> &waveform) = 0;

  virtual void InputFinished() = 0;
};


}  // namespace Kaldi

#endif  // KALDI_ITF_ONLINE_FEATURE_ITF_H_