This class takes a Matrix<BaseFloat> and wraps it as an OnlineFeatureInterface: this can be useful where some earlier stage of feature processing has been done offline but you want to use part of the online pipeline. More...

#include <online-feature.h>

Inheritance diagram for OnlineMatrixFeature:

[legend]

Collaboration diagram for OnlineMatrixFeature:

[legend]

Public Member Functions
	OnlineMatrixFeature (const MatrixBase< BaseFloat > &mat)
	Caution: this class maintains the const reference from the constructor, so don't let it go out of scope while this object exists. More...

virtual int32	Dim () const

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 bool	IsLastFrame (int32 frame) const
	Returns true if this is the last frame. More...

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
const MatrixBase< BaseFloat > &	mat_

Detailed Description

This class takes a Matrix<BaseFloat> and wraps it as an OnlineFeatureInterface: this can be useful where some earlier stage of feature processing has been done offline but you want to use part of the online pipeline.

Definition at line 167 of file online-feature.h.

Constructor & Destructor Documentation

◆ OnlineMatrixFeature()

OnlineMatrixFeature ( const MatrixBase< BaseFloat > & mat )

inlineexplicit

Caution: this class maintains the const reference from the constructor, so don't let it go out of scope while this object exists.

Definition at line 171 of file online-feature.h.

171 : mat_(mat) { }

kaldi::OnlineMatrixFeature::mat_

const MatrixBase< BaseFloat > & mat_

Definition: online-feature.h:191

Member Function Documentation

◆ Dim()

virtual int32 Dim ( ) const

inlinevirtual

Implements OnlineFeatureInterface.

Definition at line 173 of file online-feature.h.

173 { return mat_.NumCols(); }

kaldi::OnlineMatrixFeature::mat_

const MatrixBase< BaseFloat > & mat_

Definition: online-feature.h:191

◆ FrameShiftInSeconds()

virtual BaseFloat FrameShiftInSeconds ( ) const

inlinevirtual

Implements OnlineFeatureInterface.

Definition at line 175 of file online-feature.h.

                                                 {
     return 0.01f;
   }

◆ GetFrame()

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

inlinevirtual

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 181 of file online-feature.h.

References VectorBase< Real >::CopyFromVec().

                                                                   {
     feat->CopyFromVec(mat_.Row(frame));
   }

◆ 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 185 of file online-feature.h.

                                               {
     return (frame + 1 == mat_.NumRows());
   }

◆ 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 179 of file online-feature.h.

179 { return mat_.NumRows(); }

kaldi::OnlineMatrixFeature::mat_

const MatrixBase< BaseFloat > & mat_

Definition: online-feature.h:191