Audio::FRuntimeResampler Class Reference

#include <RuntimeResampler.h>

Public Member Functions
UE_API	FRuntimeResampler (int32 InNumChannels)
UE_API void	SetFrameRatio (float InRatio, int32 InNumFramesToInterpolate=0)
UE_API int32	GetNumInputFramesNeededToProduceOutputFrames (int32 InNumOutputFrames) const
UE_API int32	GetNumOutputFramesProducedByInputFrames (int32 InNumInputFrames) const
UE_API int32	ProcessCircularBuffer (FMultichannelCircularBuffer &InAudio, FMultichannelBuffer &OutAudio)
UE_API int32	ProcessCircularBuffer (FMultichannelCircularBuffer &InAudio, FMultichannelBufferView &OutAudio)
UE_API void	ProcessInterleaved (TArrayView< const float > Input, TArrayView< float > Output, int32 &OutNumInputFramesConsumed, int32 &OutNumOutputFramesProduced)
UE_API void	Reset (int32 InNumChannels)

Static Public Attributes
static UE_API const float	MaxFrameRatio = 100.f
static UE_API const float	MinFrameRatio = 0.01f

Detailed Description

Linear interpolating resampler which supports any number of channels of audio, interleaved or deinterleaved. To support different types of input and output objects, add a new "Process..." method which wraps around calls to ProcessAudioInternal().

Constructor & Destructor Documentation

FRuntimeResampler()

Audio::FRuntimeResampler::FRuntimeResampler

(

int32

InNumChannels

)

Construct a linear resampler.

Parameters

InNumChannel

- Number of audio channels in input and output buffers.

Member Function Documentation

GetNumInputFramesNeededToProduceOutputFrames()

int32 Audio::FRuntimeResampler::GetNumInputFramesNeededToProduceOutputFrames

(

int32

InNumOutputFrames

)

const

Returns the minimum number of input frames needed to produce the desired number of output frames given the current state of the resampler.

Parameters

InNumOutputFrames

- The desired number of output frames.

Returns

The minimum number of input frames.

GetNumOutputFramesProducedByInputFrames()

int32 Audio::FRuntimeResampler::GetNumOutputFramesProducedByInputFrames

(

int32

InNumInputFrames

)

const

Returns the maximum number of output frames that can be produced from the provided number of input frames given the current state of the resampler.

Parameters

InNumInputFrames

- The number of provided input frames.

Returns

The maximum number of output frames.

ProcessCircularBuffer() [1/2]

int32 Audio::FRuntimeResampler::ProcessCircularBuffer	(	FMultichannelCircularBuffer &	InAudio,
		FMultichannelBuffer &	OutAudio
	)

Consumes audio from the input buffer and produces audio in the output buffer. The desired number of frames to produce is determined by the output audio buffer size. For the desired number of samples to be produced, the input audio must have the minimum number of frames needed to produce the output frames (see GetNumInputFramesNeededToProduceOutputFrames(...)). Input samples which are no longer needed are removed from the input buffer.

Parameters

InAudio	- Multichannel circular buffer of input audio.
OutAudio	- Multichannel buffer of output audio. FMultichannelBuffer

Returns

Actual number of frames produced.

ProcessCircularBuffer() [2/2]

int32 Audio::FRuntimeResampler::ProcessCircularBuffer	(	FMultichannelCircularBuffer &	InAudio,
		FMultichannelBufferView &	OutAudio
	)

Consumes audio from the input buffer and produces audio in the output buffer. The desired number of frames to produce is determined by the output audio buffer size. For the desired number of samples to be produced, the input audio must have the minimum number of frames needed to produce the output frames (see GetNumInputFramesNeededToProduceOutputFrames(...)). Input samples which are no longer needed are removed from the input buffer.

Parameters

InAudio	- Multichannel circular buffer of input audio.
OutAudio	- Multichannel buffer of output audio. FMultichannelBuffer

Returns

Actual number of frames produced.

ProcessInterleaved()

void Audio::FRuntimeResampler::ProcessInterleaved	(	TArrayView< const float >	Input,
		TArrayView< float >	Output,
		int32 &	OutNumInputFramesConsumed,
		int32 &	OutNumOutputFramesProduced
	)

Consumes audio in an interleaved channel format from the input buffer and produces audio in the output buffer. The desired number of frames to produce is determined by the output audio buffer size. For the desired number of samples to be produced, the input audio must have the minimum number of frames needed to produce the output frames (see GetNumInputFramesNeededToProduceOutputFrames(...)).

Parameters

InAudio	- Multichannel interleaved audio to use as input.
OutAudio	- Buffer to receive multichannel interleaved output audio.
OutNumInputFramesConsumed	- Receives the actual number of frames of input consumed.
OutNumOutputFramesProduced	- Receives the actual number of frames of output produced.

Reset()

void Audio::FRuntimeResampler::Reset

(

int32

InNumChannels

)

Reset the internal state of the resampler. Call this if the next audio data to be submitted is unrelated to the audio that has been submitted previously.

SetFrameRatio()

void Audio::FRuntimeResampler::SetFrameRatio	(	float	InRatio,
		int32	InNumFramesToInterpolate = 0
	)

Sets the number of input frames to read per an output frame. 0.5 is half speed, 1.f is normal speed, 2.0 is double speed.

Parameters

InRatio	- Ratio of input frames consumed per an output frame produced.
InNumFramesToInterpolate	- Number of output frames over which to interpolate the frame ratio.

Member Data Documentation

MaxFrameRatio

const float Audio::FRuntimeResampler::MaxFrameRatio = 100.f

static

MinFrameRatio

const float Audio::FRuntimeResampler::MinFrameRatio = 0.01f

static

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

• Engine/Source/Runtime/SignalProcessing/Public/DSP/RuntimeResampler.h
• Engine/Source/Runtime/SignalProcessing/Private/RuntimeResampler.cpp