Home   Information   Classes   Download   Usage   Mail List   Requirements   Links   FAQ   Tutorial


Public Member Functions | List of all members
stk::DelayA Class Reference

STK allpass interpolating delay line class. More...

#include <DelayA.h>

Inheritance diagram for stk::DelayA:
stk::Filter stk::Stk

Public Member Functions

 DelayA (StkFloat delay=0.5, unsigned long maxDelay=4095)
 Default constructor creates a delay-line with maximum length of 4095 samples and delay = 0.5.
 
 ~DelayA ()
 Class destructor.
 
void clear (void)
 Clears all internal states of the delay line.
 
unsigned long getMaximumDelay (void)
 Get the maximum delay-line length.
 
void setMaximumDelay (unsigned long delay)
 Set the maximum delay-line length.
 
void setDelay (StkFloat delay)
 Set the delay-line length.
 
StkFloat getDelay (void) const
 Return the current delay-line length.
 
StkFloat tapOut (unsigned long tapDelay)
 Return the value at tapDelay samples from the delay-line input.
 
void tapIn (StkFloat value, unsigned long tapDelay)
 Set the value at tapDelay samples from the delay-line input.
 
StkFloat lastOut (void) const
 Return the last computed output value.
 
StkFloat nextOut (void)
 Return the value which will be output by the next call to tick().
 
StkFloat tick (StkFloat input)
 Input one sample to the filter and return one output.
 
StkFramestick (StkFrames &frames, unsigned int channel=0)
 Take a channel of the StkFrames object as inputs to the filter and replace with corresponding outputs.
 
StkFramestick (StkFrames &iFrames, StkFrames &oFrames, unsigned int iChannel=0, unsigned int oChannel=0)
 Take a channel of the iFrames object as inputs to the filter and write outputs to the oFrames object.
 
- Public Member Functions inherited from stk::Filter
 Filter (void)
 Class constructor.
 
unsigned int channelsIn (void) const
 Return the number of input channels for the class.
 
unsigned int channelsOut (void) const
 Return the number of output channels for the class.
 
virtual void clear (void)
 Clears all internal states of the filter.
 
void setGain (StkFloat gain)
 Set the filter gain.
 
StkFloat getGain (void) const
 Return the current filter gain.
 
StkFloat phaseDelay (StkFloat frequency)
 Return the filter phase delay at the specified frequency.
 
const StkFrameslastFrame (void) const
 Return an StkFrames reference to the last output sample frame.
 
virtual StkFramestick (StkFrames &frames, unsigned int channel=0)=0
 Take a channel of the StkFrames object as inputs to the filter and replace with corresponding outputs.
 
- Public Member Functions inherited from stk::Stk
void ignoreSampleRateChange (bool ignore=true)
 A function to enable/disable the automatic updating of class data when the STK sample rate changes.
 

Additional Inherited Members

- Static Public Member Functions inherited from stk::Stk
static StkFloat sampleRate (void)
 Static method that returns the current STK sample rate.
 
static void setSampleRate (StkFloat rate)
 Static method that sets the STK sample rate.
 
static void clear_alertList ()
 Static method that frees memory from alertList_.
 
static std::string rawwavePath (void)
 Static method that returns the current rawwave path.
 
static void setRawwavePath (std::string path)
 Static method that sets the STK rawwave path.
 
static void swap16 (unsigned char *ptr)
 Static method that byte-swaps a 16-bit data type.
 
static void swap32 (unsigned char *ptr)
 Static method that byte-swaps a 32-bit data type.
 
static void swap64 (unsigned char *ptr)
 Static method that byte-swaps a 64-bit data type.
 
static void sleep (unsigned long milliseconds)
 Static cross-platform method to sleep for a number of milliseconds.
 
static bool inRange (StkFloat value, StkFloat min, StkFloat max)
 Static method to check whether a value is within a specified range.
 
static void handleError (const char *message, StkError::Type type)
 Static function for error reporting and handling using c-strings.
 
static void handleError (std::string message, StkError::Type type)
 Static function for error reporting and handling using c++ strings.
 
static void showWarnings (bool status)
 Toggle display of WARNING and STATUS messages.
 
static void printErrors (bool status)
 Toggle display of error messages before throwing exceptions.
 
- Static Public Attributes inherited from stk::Stk
static const StkFormat STK_SINT8
 
static const StkFormat STK_SINT16
 
static const StkFormat STK_SINT24
 
static const StkFormat STK_SINT32
 
static const StkFormat STK_FLOAT32
 
static const StkFormat STK_FLOAT64
 
- Protected Member Functions inherited from stk::Stk
 Stk (void)
 Default constructor.
 
virtual ~Stk (void)
 Class destructor.
 
virtual void sampleRateChanged (StkFloat newRate, StkFloat oldRate)
 This function should be implemented in subclasses that depend on the sample rate.
 
void addSampleRateAlert (Stk *ptr)
 Add class pointer to list for sample rate change notification.
 
void removeSampleRateAlert (Stk *ptr)
 Remove class pointer from list for sample rate change notification.
 
void handleError (StkError::Type type) const
 Internal function for error reporting that assumes message in oStream_ variable.
 

Detailed Description

STK allpass interpolating delay line class.

This class implements a fractional-length digital delay-line using a first-order allpass filter. If the delay and maximum length are not specified during instantiation, a fixed maximum length of 4095 and a delay of 0.5 is set.

An allpass filter has unity magnitude gain but variable phase delay properties, making it useful in achieving fractional delays without affecting a signal's frequency magnitude response. In order to achieve a maximally flat phase delay response, the minimum delay possible in this implementation is limited to a value of 0.5.

by Perry R. Cook and Gary P. Scavone, 1995–2023.

Constructor & Destructor Documentation

◆ DelayA()

stk::DelayA::DelayA ( StkFloat  delay = 0.5,
unsigned long  maxDelay = 4095 
)

Default constructor creates a delay-line with maximum length of 4095 samples and delay = 0.5.

An StkError will be thrown if the delay parameter is less than zero, the maximum delay parameter is less than one, or the delay parameter is greater than the maxDelay value.

Member Function Documentation

◆ setMaximumDelay()

void stk::DelayA::setMaximumDelay ( unsigned long  delay)

Set the maximum delay-line length.

This method should generally only be used during initial setup of the delay line. If it is used between calls to the tick() function, without a call to clear(), a signal discontinuity will likely occur. If the current maximum length is greater than the new length, no memory allocation change is made.

◆ setDelay()

void stk::DelayA::setDelay ( StkFloat  delay)

Set the delay-line length.

The valid range for delay is from 0.5 to the maximum delay-line length.

◆ tapOut()

StkFloat stk::DelayA::tapOut ( unsigned long  tapDelay)

Return the value at tapDelay samples from the delay-line input.

The tap point is determined modulo the delay-line length and is relative to the last input value (i.e., a tapDelay of zero returns the last input value).

◆ nextOut()

StkFloat stk::DelayA::nextOut ( void  )
inline

Return the value which will be output by the next call to tick().

This method is valid only for delay settings greater than zero!

126{
127 if ( doNextOut_ ) {
128 // Do allpass interpolation delay.
129 nextOutput_ = -coeff_ * lastFrame_[0];
130 nextOutput_ += apInput_ + ( coeff_ * inputs_[outPoint_] );
131 doNextOut_ = false;
132 }
133
134 return nextOutput_;
135}

◆ tick() [1/2]

StkFrames & stk::DelayA::tick ( StkFrames frames,
unsigned int  channel = 0 
)
inlinevirtual

Take a channel of the StkFrames object as inputs to the filter and replace with corresponding outputs.

The StkFrames argument reference is returned. The channel argument must be less than the number of channels in the StkFrames argument (the first channel is specified by 0). However, range checking is only performed if STK_DEBUG is defined during compilation, in which case an out-of-range value will trigger an StkError exception.

Implements stk::Filter.

157{
158#if defined(_STK_DEBUG_)
159 if ( channel >= frames.channels() ) {
160 oStream_ << "DelayA::tick(): channel and StkFrames arguments are incompatible!";
161 handleError( StkError::FUNCTION_ARGUMENT );
162 }
163#endif
164
165 StkFloat *samples = &frames[channel];
166 unsigned int hop = frames.channels();
167 for ( unsigned int i=0; i<frames.frames(); i++, samples += hop ) {
168 inputs_[inPoint_++] = *samples * gain_;
169 if ( inPoint_ == inputs_.size() ) inPoint_ = 0;
170 *samples = nextOut();
171 lastFrame_[0] = *samples;
172 doNextOut_ = true;
173 apInput_ = inputs_[outPoint_++];
174 if ( outPoint_ == inputs_.size() ) outPoint_ = 0;
175 }
176
177 return frames;
178}
StkFloat nextOut(void)
Return the value which will be output by the next call to tick().
Definition DelayA.h:125
size_t size() const
Returns the total number of audio samples represented by the object.
Definition Stk.h:374
static void handleError(const char *message, StkError::Type type)
Static function for error reporting and handling using c-strings.

◆ tick() [2/2]

StkFrames & stk::DelayA::tick ( StkFrames iFrames,
StkFrames oFrames,
unsigned int  iChannel = 0,
unsigned int  oChannel = 0 
)
inline

Take a channel of the iFrames object as inputs to the filter and write outputs to the oFrames object.

The iFrames object reference is returned. Each channel argument must be less than the number of channels in the corresponding StkFrames argument (the first channel is specified by 0). However, range checking is only performed if STK_DEBUG is defined during compilation, in which case an out-of-range value will trigger an StkError exception.

181{
182#if defined(_STK_DEBUG_)
183 if ( iChannel >= iFrames.channels() || oChannel >= oFrames.channels() ) {
184 oStream_ << "DelayA::tick(): channel and StkFrames arguments are incompatible!";
185 handleError( StkError::FUNCTION_ARGUMENT );
186 }
187#endif
188
189 StkFloat *iSamples = &iFrames[iChannel];
190 StkFloat *oSamples = &oFrames[oChannel];
191 unsigned int iHop = iFrames.channels(), oHop = oFrames.channels();
192 for ( unsigned int i=0; i<iFrames.frames(); i++, iSamples += iHop, oSamples += oHop ) {
193 inputs_[inPoint_++] = *iSamples * gain_;
194 if ( inPoint_ == inputs_.size() ) inPoint_ = 0;
195 *oSamples = nextOut();
196 lastFrame_[0] = *oSamples;
197 doNextOut_ = true;
198 apInput_ = inputs_[outPoint_++];
199 if ( outPoint_ == inputs_.size() ) outPoint_ = 0;
200 }
201
202 return iFrames;
203}

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

The Synthesis ToolKit in C++ (STK)
©1995--2023 Perry R. Cook and Gary P. Scavone. All Rights Reserved.