FX Class: Bitcrusher

Interactive example

Bitcrusher Demo
100%
All controls are available across their full ranges. This allows for extreme settings which may cause undesirable audio artifacts such as static, distortion or buzzing.

Overview

Bitcrusher is an audio effect simulating an old-school digital sound card by reducing the resolution or bandwidth of digital audio data. Depending on the values of the adjustable frequency and bits properties the resulting noise may produce a warm or hard impression.

It doesn't allocate any internal buffers and needs just a few bytes of memory.


Implementation example

The bitcrusher is an FX class, it expects both an input and output buffer. The process() function should be called on every loop of the audio processing block.

class SuperpoweredBitcrusherProcessor extends SuperpoweredWebAudio.AudioWorkletProcessor {
// Called when the AudioWorklet is ready to start processing audio
onReady() {
this.bitcrusher = new this.Superpowered.Bitcrusher(
44100 // The initial sample rate in Hz. -
);
this.bitcrusher.enabled = true;
}
// Runs before the node is destroyed.
// Clean up memory and objects here (such as free allocated linear memory or destruct Superpowered objects).
onDestruct() {
this.bitcrusher.destruct();
}
// The shape of the message we pass from our main thread is up to you
onMessageFromMainScope(message) {
// Here is an example of how to apply changes to the Three Band EQ instance
if (typeof message.bits !== 'undefined') this.bitcrusher.bits = message.bits;
if (typeof message.frequency !== 'undefined') this.bitcrusher.frequency = message.frequency;
}
// This is the process loop which is passed pointers to buffers
// from the WebAudio API (inputBuffer and outputBuffer), with the buffersize (128 samples when running as a native AudioWorklet)
processAudio(inputBuffer, outputBuffer, buffersize) {
// Ensure the samplerate is in sync on every audio processing callback
this.bitcrusher.samplerate = this.samplerate;
// Render the output buffers
if (!this.bitcrusher.process(inputBuffer.pointer, outputBuffer.pointer, buffersize)) {
for (let n = 0; n < buffersize * 2 ; n++) outputBuffer.array[n] = inputBuffer.array[n];
}
}
}
#include "SuperpoweredBitcrusher.h"
void initBitcrusherEffect() {
unsigned int sampleRate = 44100;
bitcrusher = new Superpowered::Bitcrusher(sampleRate);
bitcrusher->frequency = 8000;
bitcrusher->bits = 8;
bitcrusher->enabled = true;
}
void processAudio(float *interleavedInput, float *interleavedOutput, unsigned int numberOfFrames, unsigned int samplerate) {
// Ensure the samplerate is in sync on every audio processing callback
bitcrusher->samplerate = samplerate;
// Render the output buffers
bool outputChanged = bitcrusher->process(interleavedInput, interleavedOutput, numberOfFrames);
...
}

Properties

bits

PROPERTY
Bit depth
TypeMinMaxDefault
Number
1168

bits

PROPERTY
Bit depth
TypeMinMaxDefault
unsigned char
1168

frequency

PROPERTY
Frequency in Hz, from 20 Hz to the half of the samplerate.
TypeMinMaxDefault
Number
20Half of your sample rate.8000

frequency

PROPERTY
Frequency in Hz, from 20 Hz to the half of the samplerate.
TypeMinMaxDefault
unsigned int
20Half of your sample rate.8000
Inherited from FX Class

enabled

PROPERTY
Turns the effect on/off. The actual switch will happen on the next process() call for smooth, audio-artifact free operation.
TypeMinMaxDefault
Boolean
false

enabled

PROPERTY
Turns the effect on/off. The actual switch will happen on the next process() call for smooth, audio-artifact free operation.
TypeMinMaxDefault
bool
false

samplerate

PROPERTY
The sample rate of the audio context, you must update if it changes.
TypeMinMaxDefault
Number

samplerate

PROPERTY
The sample rate of the audio context, you must update if it changes.
TypeMinMaxDefault
unsigned int

Methods

  • constructor

    METHOD
    Creates an instance of Bitcrusher class.
    Parameters
    NameTypeDescription
    samplerateNumberThe initial sample rate in Hz.
    Returns
    TypeDescription
    Superpowered.BitcrusherThe constructed instance.
  • constructor

    METHOD
    Creates an instance of Bitcrusher class.
    Parameters
    NameTypeDefaultDescription
    samplerateunsigned intThe initial sample rate in Hz.
    Returns
    TypeDescription
    Superpowered::BitcrusherThe constructed instance.
Inherited from FX Class
  • destruct

    METHOD
    Destructor to free Linear Memory.
    Parameters
    None
    Returns
    None
  • process

    METHOD
    Processes/renders the audio. Always call it in the audio processing callback, regardless if the effect is enabled or not for smooth, audio-artifact free operation. It's never blocking for real-time usage.
    Parameters
    NameTypeDescription
    inputNumber (pointer in Linear Memory)32-bit interleaved stereo input.
    outputNumber (pointer in Linear Memory)32-bit interleaved stereo output.
    numberOfFramesNumberNumber of frames to process. Recommendations for best performance: multiply of 4, minimum 64.
    Returns
    TypeDescription
    BooleanIf process() returns with true, the contents of output are replaced with the audio output. If process() returns with false, it indicates silence. The contents of output are not changed in this case (not overwritten with zeros).
  • process

    METHOD
    Processes/renders the audio. Always call it in the audio processing callback, regardless if the effect is enabled or not for smooth, audio-artifact free operation. It's never blocking for real-time usage. You can change all effect properties on any thread, concurrently with process().
    Parameters
    NameTypeDefaultDescription
    inputfloat *32-bit interleaved stereo input.
    outputfloat *32-bit interleaved stereo output.
    numberOfFramesunsigned intNumber of frames to process. Recommendations for best performance: multiply of 4, minimum 64.
    Returns
    TypeDescription
    boolIf process() returns with true, the contents of output are replaced with the audio output. If process() returns with false, it indicates silence. The contents of output are not changed in this case (not overwritten with zeros).
v1.0.6