OnlineAppendFeature Class Reference

This online-feature class implements combination of two feature streams (such as pitch, plp) into one stream. More...

#include <online-feature.h>

Inheritance diagram for OnlineAppendFeature:

Collaboration diagram for OnlineAppendFeature:

Public Member Functions
virtual int32	Dim () const
virtual bool	IsLastFrame (int32 frame) const
	Returns true if this is the last frame. More...
virtual BaseFloat	FrameShiftInSeconds () const
virtual int32	NumFramesReady () const
	returns the feature dimension. More...
virtual void	GetFrame (int32 frame, VectorBase< BaseFloat > *feat)
	Gets the feature vector for this frame. More...
virtual	~OnlineAppendFeature ()
	OnlineAppendFeature (OnlineFeatureInterface *src1, OnlineFeatureInterface *src2)
Public Member Functions inherited from OnlineFeatureInterface
virtual void	GetFrames (const std::vector< int32 > &frames, MatrixBase< BaseFloat > *feats)
	This is like GetFrame() but for a collection of frames. More...
virtual	~OnlineFeatureInterface ()
	Virtual destructor. More...

Private Attributes
OnlineFeatureInterface *	src1_
OnlineFeatureInterface *	src2_

Detailed Description

This online-feature class implements combination of two feature streams (such as pitch, plp) into one stream.

Definition at line 601 of file online-feature.h.

Constructor & Destructor Documentation

~OnlineAppendFeature()

virtual ~OnlineAppendFeature ( )

inlinevirtual

Definition at line 619 of file online-feature.h.

{  }

OnlineAppendFeature()

OnlineAppendFeature ( OnlineFeatureInterface *  src1, OnlineFeatureInterface *  src2  )

inline

Definition at line 621 of file online-feature.h.

                                   : src1_(src1), src2_(src2) { }

Member Function Documentation

Dim()

virtual int32 Dim ( ) const

inlinevirtual

Implements OnlineFeatureInterface.

Definition at line 603 of file online-feature.h.

{ return src1_->Dim() + src2_->Dim(); }

FrameShiftInSeconds()

virtual BaseFloat FrameShiftInSeconds ( ) const

inlinevirtual

Implements OnlineFeatureInterface.

Definition at line 609 of file online-feature.h.

                                                {
    return src1_->FrameShiftInSeconds();
  }

GetFrame()

void GetFrame ( int32  frame, VectorBase< BaseFloat > *  feat  )

virtual

Gets the feature vector for this frame.

Before calling this for a given frame, it is assumed that you called NumFramesReady() and it returned a number greater than "frame". Otherwise this call will likely crash with an assert failure. This function is not declared const, in case there is some kind of caching going on, but most of the time it shouldn't modify the class.

Implements OnlineFeatureInterface.

Definition at line 669 of file online-feature.cc.

References VectorBase< Real >::Dim(), OnlineDeltaFeature::Dim(), and KALDI_ASSERT.

                                                                           {
  KALDI_ASSERT(feat->Dim() == Dim());

  SubVector<BaseFloat> feat1(*feat, 0, src1_->Dim());
  SubVector<BaseFloat> feat2(*feat, src1_->Dim(), src2_->Dim());
  src1_->GetFrame(frame, &feat1);
  src2_->GetFrame(frame, &feat2);
};

IsLastFrame()

virtual bool IsLastFrame ( int32  frame ) const

inlinevirtual

Returns true if this is the last frame.

Frame indices are zero-based, so the first frame is zero. IsLastFrame(-1) will return false, unless the file is empty (which is a case that I'm not sure all the code will handle, so be careful). This function may return false for some frame if we haven't yet decided to terminate decoding, but later true if we decide to terminate decoding. This function exists mainly to correctly handle end effects in feature extraction, and is not a mechanism to determine how many frames are in the decodable object (as it used to be, and for backward compatibility, still is, in the Decodable interface).

Implements OnlineFeatureInterface.

Definition at line 605 of file online-feature.h.

                                              {
    return (src1_->IsLastFrame(frame) || src2_->IsLastFrame(frame));
  }

NumFramesReady()

virtual int32 NumFramesReady ( ) const

inlinevirtual

returns the feature dimension.

Returns the total number of frames, since the start of the utterance, that are now available. In an online-decoding context, this will likely increase with time as more data becomes available.

Implements OnlineFeatureInterface.

Definition at line 613 of file online-feature.h.

                                       {
    return std::min(src1_->NumFramesReady(), src2_->NumFramesReady());
  }

Member Data Documentation

src1_

OnlineFeatureInterface* src1_

private

Definition at line 625 of file online-feature.h.

src2_

OnlineFeatureInterface* src2_

private

Definition at line 626 of file online-feature.h.

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

• feat/online-feature.h
• feat/online-feature.cc