Delayline

Allow to sample signal back in time. This delay-line has a twin write index, so that the read pointer can read a contiguous memory area. ____________________________________________________________________________________ | | _index | | readPointer = _index + half size | |

A Delayline is initialized with an internal length of N = numSamples,
in order to do a simple delay of N samples.
Internally, the delayline actually has 2 x nextPow2(N + 1) samples of storage.
So typically a delay line is initialized with maxDelaySamples + maxFrames (if buffering is used)..

Example:

import dplug.dsp.delayline;

void delaySampleBySample() // slower method, but easier to be correct { Delayline!float delayline; delayline.initialize(maxPossibleDelay); for (int n = 0; n < frames; ++n) { delayline.feedSample(inputn);

// desiredDelay = 0 would be the sample we just fed // the delayline with. delayedn = delayline.fullSample(desiredDelay); } }

void delayUsingReadPointer() // fastest method, but more confusing { Delayline!float delayline; delayline.initialize(maxFrames + maxPossibleDelay); delayline.feedBuffer(input.ptr, frames); const(float)* readPtr = d.readPointer() - desiredDelay - frames + 1; delayed[0..frames] = readPtr[0..frames]; // Caveats: frames <= maxFrames and desiredDelay <= maxPossibleDelay. }

struct Delayline (

) {

void initialize(int numSamples);

~this();

this(this);

void resize(int numSamples);

T nextSample(T incoming);

void nextBuffer(const(T)* input, T* output, int frames);

void feedSample(T incoming);

void feedBuffer(const(T)[] incoming);

void feedBuffer(const(T)* incoming, size_t count);

const(T)* readPointer();

T sampleFull(int delay);

void sampleFullBuffer(int delayOfMostRecentSample, float* outBuffer, int frames);

static if(is(T == float) || is(T == double))

T sampleLinear(float delay);

static if(is(T == float) || is(T == double))

T sampleHermite(float delay);

static if(is(T == float) || is(T == double))

T sampleSpline3(float delay);

static if(is(T == float) || is(T == double))

T sampleSpline4(float delay);

}

Destructor

~this ~this(): Undocumented in source.

Postblit

this(this) this(this): Undocumented in source.

Members

Functions

feedBuffer void feedBuffer(const(T)[] incoming)
void feedBuffer(const(T)* incoming, size_t count): Adds several samples at end of delay.
feedSample void feedSample(T incoming): Adds a new sample at end of delay.
initialize void initialize(int numSamples): Initialize the delay line. Can delay up to numSamples samples.
nextBuffer void nextBuffer(const(T)* input, T* output, int frames): Combined feed + sampleFull. Uses the delay line as a fixed delay of count samples.
nextSample T nextSample(T incoming): Combined feed + sampleFull. Uses the delay line as a fixed delay of count samples.
readPointer const(T)* readPointer()
resize void resize(int numSamples): Resize the delay line. Can delay up to count samples. The state is cleared.
sampleFull T sampleFull(int delay): Random access sampling of the delay-line at integer points. Delay 0 = last entered sample with feed().
sampleFullBuffer void sampleFullBuffer(int delayOfMostRecentSample, float* outBuffer, int frames): Random access sampling of the delay-line at integer points, extract a time slice. Delay 0 = last entered sample with feed().
sampleHermite T sampleHermite(float delay): Random access sampling of the delay-line with a 3rd order polynomial.
sampleLinear T sampleLinear(float delay): Random access sampling of the delay-line with linear interpolation.
sampleSpline3 T sampleSpline3(float delay): Third-order spline interpolation http://musicdsp.org/showArchiveComment.php?ArchiveID=62
sampleSpline4 T sampleSpline4(float delay): 4th order spline interpolation http://musicdsp.org/showArchiveComment.php?ArchiveID=60

Delayline

Destructor

Postblit

Members

Functions

Meta

Source