From c790f40b4bd1aafd4e25c731574c57d8063a4c43 Mon Sep 17 00:00:00 2001 From: sbosse Date: Mon, 21 Jul 2025 23:13:52 +0200 Subject: [PATCH] Mon 21 Jul 22:43:21 CEST 2025 --- js/dsp/dsp.js | 2474 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 2474 insertions(+) create mode 100644 js/dsp/dsp.js diff --git a/js/dsp/dsp.js b/js/dsp/dsp.js new file mode 100644 index 0000000..0a2407e --- /dev/null +++ b/js/dsp/dsp.js @@ -0,0 +1,2474 @@ +/* + * DSP.js - a comprehensive digital signal processing library for javascript + * + * Created by Corban Brook on 2010-01-01. + * Copyright 2010 Corban Brook. All rights reserved. + * + * Modified by Stefan Bosse on 2018 + * + */ +var current=none; +var Aios=none; + +//////////////////////////////////////////////////////////////////////////////// +// CONSTANTS // +//////////////////////////////////////////////////////////////////////////////// + +/** + * DSP is an object which contains general purpose utility functions and constants + */ +var DSP = { + // Channels + LEFT: 0, + RIGHT: 1, + MIX: 2, + + // Waveforms + SINE: 1, + TRIANGLE: 2, + SAW: 3, + SQUARE: 4, + + // Filters + LOWPASS: 0, + HIGHPASS: 1, + BANDPASS: 2, + NOTCH: 3, + + // Window functions + BARTLETT: 1, + BARTLETTHANN: 2, + BLACKMAN: 3, + COSINE: 4, + GAUSS: 5, + HAMMING: 6, + HANN: 7, + LANCZOS: 8, + RECTANGULAR: 9, + TRIANGULAR: 10, + + // Mean Filter + ARITH: 0, + EXP: 1, + PEAK: 2, + + // Loop modes + OFF: 0, + FW: 1, + BW: 2, + FWBW: 3, + + // Math + TWO_PI: 2*Math.PI +}; + +// Setup arrays for platforms which do not support byte arrays +function setupTypedArray(name, fallback) { + // check if TypedArray exists + // typeof on Minefield and Chrome return function, typeof on Webkit returns object. + if (typeof this[name] !== "function" && typeof this[name] !== "object") { + // nope.. check if WebGLArray exists + if (typeof this[fallback] === "function" && typeof this[fallback] !== "object") { + this[name] = this[fallback]; + } else { + // nope.. set as Native JS array + this[name] = function(obj) { + if (obj instanceof Array) { + return obj; + } else if (typeof obj === "number") { + return new Array(obj); + } + }; + } + } +} + +setupTypedArray("Float64Array", "WebGLFloatArray"); +setupTypedArray("Int32Array", "WebGLIntArray"); +setupTypedArray("Uint16Array", "WebGLUnsignedShortArray"); +setupTypedArray("Uint8Array", "WebGLUnsignedByteArray"); + + +//////////////////////////////////////////////////////////////////////////////// +// DSP UTILITY FUNCTIONS // +//////////////////////////////////////////////////////////////////////////////// + +/** + * Inverts the phase of a signal + * + * @param {Array} buffer A sample buffer + * + * @returns The inverted sample buffer + */ +DSP.invert = function(buffer) { + for (var i = 0, len = buffer.length; i < len; i++) { + buffer[i] *= -1; + } + + return buffer; +}; + +/** + * Converts split-stereo (dual mono) sample buffers into a stereo interleaved sample buffer + * + * @param {Array} left A sample buffer + * @param {Array} right A sample buffer + * + * @returns The stereo interleaved buffer + */ +DSP.interleave = function(left, right) { + if (left.length !== right.length) { + throw "Can not interleave. Channel lengths differ."; + } + + var stereoInterleaved = new Float64Array(left.length * 2); + + for (var i = 0, len = left.length; i < len; i++) { + stereoInterleaved[2*i] = left[i]; + stereoInterleaved[2*i+1] = right[i]; + } + + return stereoInterleaved; +}; + +/** + * Converts a stereo-interleaved sample buffer into split-stereo (dual mono) sample buffers + * + * @param {Array} buffer A stereo-interleaved sample buffer + * + * @returns an Array containing left and right channels + */ +DSP.deinterleave = (function() { + var left, right, mix, deinterleaveChannel = []; + + deinterleaveChannel[DSP.MIX] = function(buffer) { + for (var i = 0, len = buffer.length/2; i < len; i++) { + mix[i] = (buffer[2*i] + buffer[2*i+1]) / 2; + } + return mix; + }; + + deinterleaveChannel[DSP.LEFT] = function(buffer) { + for (var i = 0, len = buffer.length/2; i < len; i++) { + left[i] = buffer[2*i]; + } + return left; + }; + + deinterleaveChannel[DSP.RIGHT] = function(buffer) { + for (var i = 0, len = buffer.length/2; i < len; i++) { + right[i] = buffer[2*i+1]; + } + return right; + }; + + return function(channel, buffer) { + left = left || new Float64Array(buffer.length/2); + right = right || new Float64Array(buffer.length/2); + mix = mix || new Float64Array(buffer.length/2); + + if (buffer.length/2 !== left.length) { + left = new Float64Array(buffer.length/2); + right = new Float64Array(buffer.length/2); + mix = new Float64Array(buffer.length/2); + } + + return deinterleaveChannel[channel](buffer); + }; +}()); + +/** + * Separates a channel from a stereo-interleaved sample buffer + * + * @param {Array} buffer A stereo-interleaved sample buffer + * @param {Number} channel A channel constant (LEFT, RIGHT, MIX) + * + * @returns an Array containing a signal mono sample buffer + */ +DSP.getChannel = DSP.deinterleave; + +/** + * Helper method (for Reverb) to mix two (interleaved) samplebuffers. It's possible + * to negate the second buffer while mixing and to perform a volume correction + * on the final signal. + * + * @param {Array} sampleBuffer1 Array containing Float values or a Float64Array + * @param {Array} sampleBuffer2 Array containing Float values or a Float64Array + * @param {Boolean} negate When true inverts/flips the audio signal + * @param {Number} volumeCorrection When you add multiple sample buffers, use this to tame your signal ;) + * + * @returns A new Float64Array interleaved buffer. + */ +DSP.mixSampleBuffers = function(sampleBuffer1, sampleBuffer2, negate, volumeCorrection){ + var outputSamples = new Float64Array(sampleBuffer1); + + for(var i = 0; i peak) ? Math.abs(buffer[i]) : peak; + } + + return peak; +}; + +// Get features of a signal [min,max,mean,deviation} +DSP.Features = function(buffer) { + var i,x, + ft = { min:Number.MAX_VALUE, max:Number.MIN_VALUE, mean:0.0, deviation:0.0 }; + for(i=0;i0 && (i%k)==0) { + output[j]=y; j++; + y=0;n=1; + } + case DSP.ARITH: + y=y+buffer[i]; n++; + if (i>0 && (i%k)==0) { + output[j]=(y/n); j++; + y=0;n=1; + } + break; + case DSP.PEAK: + if (first) y=buffer[i]; + y=Math.max(y,buffer[i]); + if (i>0 && (i%k)==0) { + output[j]=y; j++; + y=0;n=1;first=true; + } + break; + } + first=false; + } + if (filter==DSP.ARITH) {output[j]=(y/n); j++} + return output; +} + +DSP.Resample = function(buffer, divider, filter) { + return DSP.Reduce(buffer,(buffer.length/divider)|0,filter); +} + +// Add noise (sample + [-noise,+noise] random interval) +DSP.Noise = function(buffer,noise,random,inplace) { + var ouput; + if (inplace) output=buffer; + else if(buffer instanceof Array) output=new Array(buffer.length); + else if(buffer instanceof Float32Array) output=new Float32Array(buffer.length); + else if(buffer instanceof Float64Array) output=new Float64Array(buffer.length); + if (!random) random=function(e) {return -e+2*e*Math.random()}; + for(var i=0;i < buffer.length;i++) output[i]=buffer[i]+random(noise); +} + +// Fourier Transform Module used by DFT, FFT, RFFT +function FourierTransform(bufferSize, sampleRate) { + this.bufferSize = bufferSize; + this.sampleRate = sampleRate; + this.bandwidth = 2 / bufferSize * sampleRate / 2; + + this.spectrum = new Float64Array(bufferSize/2); + this.real = new Float64Array(bufferSize); + this.imag = new Float64Array(bufferSize); + + this.peakBand = 0; + this.peak = 0; + + /** + * Calculates the *middle* frequency of an FFT band. + * + * @param {Number} index The index of the FFT band. + * + * @returns The middle frequency in Hz. + */ + this.getBandFrequency = function(index) { + return this.bandwidth * index + this.bandwidth / 2; + }; + + this.calculateSpectrum = function() { + var spectrum = this.spectrum, + real = this.real, + imag = this.imag, + bSi = 2 / this.bufferSize, + sqrt = Math.sqrt, + rval, + ival, + mag; + + for (var i = 0, N = bufferSize/2; i < N; i++) { + rval = real[i]; + ival = imag[i]; + mag = bSi * sqrt(rval * rval + ival * ival); + + if (mag > this.peak) { + this.peakBand = i; + this.peak = mag; + } + + spectrum[i] = mag; + } + + return spectrum; + }; +} + +/** + * DFT is a class for calculating the Discrete Fourier Transform of a signal. + * + * @param {Number} bufferSize The size of the sample buffer to be computed + * @param {Number} sampleRate The sampleRate of the buffer (eg. 44100) + * + * @constructor + */ +function DFT(bufferSize, sampleRate) { + FourierTransform.call(this, bufferSize, sampleRate); + + var N = bufferSize/2 * bufferSize; + var TWO_PI = 2 * Math.PI; + + this.sinTable = new Float64Array(N); + this.cosTable = new Float64Array(N); + + for (var i = 0; i < N; i++) { + this.sinTable[i] = Math.sin(i * TWO_PI / bufferSize); + this.cosTable[i] = Math.cos(i * TWO_PI / bufferSize); + } +} + +/** + * Performs a forward transform on the sample buffer. + * Converts a time domain signal to frequency domain spectra. + * + * @param {Array} buffer The sample buffer + * + * @returns The frequency spectrum array + */ +DFT.prototype.forward = function(buffer,spectrum) { + var real = this.real, + imag = this.imag, + rval, + ival; + + for (var k = 0; k < this.bufferSize/2; k++) { + rval = 0.0; + ival = 0.0; + + for (var n = 0; n < buffer.length; n++) { + rval += this.cosTable[k*n] * buffer[n]; + ival += this.sinTable[k*n] * buffer[n]; + } + + real[k] = rval; + imag[k] = ival; + } + + return spectrum?this.calculateSpectrum():{real:this.real,imag:this.imag}; +}; + + +/** + * FFT is a class for calculating the Discrete Fourier Transform of a signal + * with the Fast Fourier Transform algorithm. + * + * @param {Number} bufferSize The size of the sample buffer to be computed. Must be power of 2 + * @param {Number} sampleRate The sampleRate of the buffer (eg. 44100) + * + * @constructor + */ +function FFT(bufferSize, sampleRate) { + if (!(this instanceof FFT)) return new FFT(bufferSize, sampleRate); + FourierTransform.call(this, bufferSize, sampleRate); + + this.reverseTable = new Uint32Array(bufferSize); + + var limit = 1; + var bit = bufferSize >> 1; + + var i; + + while (limit < bufferSize) { + for (i = 0; i < limit; i++) { + this.reverseTable[i + limit] = this.reverseTable[i] + bit; + } + + limit = limit << 1; + bit = bit >> 1; + } + + this.sinTable = new Float64Array(bufferSize); + this.cosTable = new Float64Array(bufferSize); + + for (i = 0; i < bufferSize; i++) { + this.sinTable[i] = Math.sin(-Math.PI/i); + this.cosTable[i] = Math.cos(-Math.PI/i); + } +} + +/** + * Performs a forward transform on the sample buffer. + * Converts a time domain signal to frequency domain spectra. + * + * @param {Array} buffer The sample buffer. Buffer Length must be power of 2 + * + * @returns The frequency spectrum array + */ +FFT.prototype.forward = function(buffer,spectrum) { + // Locally scope variables for speed up + var bufferSize = this.bufferSize, + cosTable = this.cosTable, + sinTable = this.sinTable, + reverseTable = this.reverseTable, + real = this.real, + imag = this.imag, + spectrum = this.spectrum; + + var k = Math.floor(Math.log(bufferSize) / Math.LN2); + + if (Math.pow(2, k) !== bufferSize) { throw "Invalid buffer size, must be a power of 2."; } + if (bufferSize !== buffer.length) { throw "Supplied buffer is not the same size as defined FFT. FFT Size: " + bufferSize + " Buffer Size: " + buffer.length; } + + var halfSize = 1, + phaseShiftStepReal, + phaseShiftStepImag, + currentPhaseShiftReal, + currentPhaseShiftImag, + off, + tr, + ti, + tmpReal, + i; + + for (i = 0; i < bufferSize; i++) { + real[i] = buffer[reverseTable[i]]; + imag[i] = 0; + } + + while (halfSize < bufferSize) { + //phaseShiftStepReal = Math.cos(-Math.PI/halfSize); + //phaseShiftStepImag = Math.sin(-Math.PI/halfSize); + phaseShiftStepReal = cosTable[halfSize]; + phaseShiftStepImag = sinTable[halfSize]; + + currentPhaseShiftReal = 1; + currentPhaseShiftImag = 0; + + for (var fftStep = 0; fftStep < halfSize; fftStep++) { + i = fftStep; + + while (i < bufferSize) { + off = i + halfSize; + tr = (currentPhaseShiftReal * real[off]) - (currentPhaseShiftImag * imag[off]); + ti = (currentPhaseShiftReal * imag[off]) + (currentPhaseShiftImag * real[off]); + + real[off] = real[i] - tr; + imag[off] = imag[i] - ti; + real[i] += tr; + imag[i] += ti; + + i += halfSize << 1; + } + + tmpReal = currentPhaseShiftReal; + currentPhaseShiftReal = (tmpReal * phaseShiftStepReal) - (currentPhaseShiftImag * phaseShiftStepImag); + currentPhaseShiftImag = (tmpReal * phaseShiftStepImag) + (currentPhaseShiftImag * phaseShiftStepReal); + } + + halfSize = halfSize << 1; + } + + return spectrum?this.calculateSpectrum():{real:this.real,imag:this.imag}; +}; + +FFT.prototype.inverse = function(real, imag) { + // Locally scope variables for speed up + var bufferSize = this.bufferSize, + cosTable = this.cosTable, + sinTable = this.sinTable, + reverseTable = this.reverseTable, + spectrum = this.spectrum; + + real = real || this.real; + imag = imag || this.imag; + + var halfSize = 1, + phaseShiftStepReal, + phaseShiftStepImag, + currentPhaseShiftReal, + currentPhaseShiftImag, + off, + tr, + ti, + tmpReal, + i; + + for (i = 0; i < bufferSize; i++) { + imag[i] *= -1; + } + + var revReal = new Float64Array(bufferSize); + var revImag = new Float64Array(bufferSize); + + for (i = 0; i < real.length; i++) { + revReal[i] = real[reverseTable[i]]; + revImag[i] = imag[reverseTable[i]]; + } + + real = revReal; + imag = revImag; + + while (halfSize < bufferSize) { + phaseShiftStepReal = cosTable[halfSize]; + phaseShiftStepImag = sinTable[halfSize]; + currentPhaseShiftReal = 1; + currentPhaseShiftImag = 0; + + for (var fftStep = 0; fftStep < halfSize; fftStep++) { + i = fftStep; + + while (i < bufferSize) { + off = i + halfSize; + tr = (currentPhaseShiftReal * real[off]) - (currentPhaseShiftImag * imag[off]); + ti = (currentPhaseShiftReal * imag[off]) + (currentPhaseShiftImag * real[off]); + + real[off] = real[i] - tr; + imag[off] = imag[i] - ti; + real[i] += tr; + imag[i] += ti; + + i += halfSize << 1; + } + + tmpReal = currentPhaseShiftReal; + currentPhaseShiftReal = (tmpReal * phaseShiftStepReal) - (currentPhaseShiftImag * phaseShiftStepImag); + currentPhaseShiftImag = (tmpReal * phaseShiftStepImag) + (currentPhaseShiftImag * phaseShiftStepReal); + } + + halfSize = halfSize << 1; + } + + var buffer = new Float64Array(bufferSize); // this should be reused instead + for (i = 0; i < bufferSize; i++) { + buffer[i] = real[i] / bufferSize; + } + + return buffer; +}; + +/** + * RFFT is a class for calculating the Discrete Fourier Transform of a signal + * with the Fast Fourier Transform algorithm. + * + * This method currently only contains a forward transform but is highly optimized. + * + * @param {Number} bufferSize The size of the sample buffer to be computed. Must be power of 2 + * @param {Number} sampleRate The sampleRate of the buffer (eg. 44100) + * + * @constructor + */ + +// lookup tables don't really gain us any speed, but they do increase +// cache footprint, so don't use them in here + +// also we don't use sepearate arrays for real/imaginary parts + +// this one a little more than twice as fast as the one in FFT +// however I only did the forward transform + +// the rest of this was translated from C, see http://www.jjj.de/fxt/ +// this is the real split radix FFT + +function RFFT(bufferSize, sampleRate) { + FourierTransform.call(this, bufferSize, sampleRate); + + this.trans = new Float64Array(bufferSize); + + this.reverseTable = new Uint32Array(bufferSize); + + // don't use a lookup table to do the permute, use this instead + this.reverseBinPermute = function (dest, source) { + var bufferSize = this.bufferSize, + halfSize = bufferSize >>> 1, + nm1 = bufferSize - 1, + i = 1, r = 0, h; + + dest[0] = source[0]; + + do { + r += halfSize; + dest[i] = source[r]; + dest[r] = source[i]; + + i++; + + h = halfSize << 1; + while (h = h >> 1, !((r ^= h) & h)); + + if (r >= i) { + dest[i] = source[r]; + dest[r] = source[i]; + + dest[nm1-i] = source[nm1-r]; + dest[nm1-r] = source[nm1-i]; + } + i++; + } while (i < halfSize); + dest[nm1] = source[nm1]; + }; + + this.generateReverseTable = function () { + var bufferSize = this.bufferSize, + halfSize = bufferSize >>> 1, + nm1 = bufferSize - 1, + i = 1, r = 0, h; + + this.reverseTable[0] = 0; + + do { + r += halfSize; + + this.reverseTable[i] = r; + this.reverseTable[r] = i; + + i++; + + h = halfSize << 1; + while (h = h >> 1, !((r ^= h) & h)); + + if (r >= i) { + this.reverseTable[i] = r; + this.reverseTable[r] = i; + + this.reverseTable[nm1-i] = nm1-r; + this.reverseTable[nm1-r] = nm1-i; + } + i++; + } while (i < halfSize); + + this.reverseTable[nm1] = nm1; + }; + + this.generateReverseTable(); +} + + +// Ordering of output: +// +// trans[0] = re[0] (==zero frequency, purely real) +// trans[1] = re[1] +// ... +// trans[n/2-1] = re[n/2-1] +// trans[n/2] = re[n/2] (==nyquist frequency, purely real) +// +// trans[n/2+1] = im[n/2-1] +// trans[n/2+2] = im[n/2-2] +// ... +// trans[n-1] = im[1] + +RFFT.prototype.forward = function(buffer) { + var n = this.bufferSize, + spectrum = this.spectrum, + x = this.trans, + TWO_PI = 2*Math.PI, + sqrt = Math.sqrt, + i = n >>> 1, + bSi = 2 / n, + n2, n4, n8, nn, + t1, t2, t3, t4, + i1, i2, i3, i4, i5, i6, i7, i8, + st1, cc1, ss1, cc3, ss3, + e, + a, + rval, ival, mag; + + this.reverseBinPermute(x, buffer); + + /* + var reverseTable = this.reverseTable; + + for (var k = 0, len = reverseTable.length; k < len; k++) { + x[k] = buffer[reverseTable[k]]; + } + */ + + for (var ix = 0, id = 4; ix < n; id *= 4) { + for (var i0 = ix; i0 < n; i0 += id) { + //sumdiff(x[i0], x[i0+1]); // {a, b} <--| {a+b, a-b} + st1 = x[i0] - x[i0+1]; + x[i0] += x[i0+1]; + x[i0+1] = st1; + } + ix = 2*(id-1); + } + + n2 = 2; + nn = n >>> 1; + + while((nn = nn >>> 1)) { + ix = 0; + n2 = n2 << 1; + id = n2 << 1; + n4 = n2 >>> 2; + n8 = n2 >>> 3; + do { + if(n4 !== 1) { + for(i0 = ix; i0 < n; i0 += id) { + i1 = i0; + i2 = i1 + n4; + i3 = i2 + n4; + i4 = i3 + n4; + + //diffsum3_r(x[i3], x[i4], t1); // {a, b, s} <--| {a, b-a, a+b} + t1 = x[i3] + x[i4]; + x[i4] -= x[i3]; + //sumdiff3(x[i1], t1, x[i3]); // {a, b, d} <--| {a+b, b, a-b} + x[i3] = x[i1] - t1; + x[i1] += t1; + + i1 += n8; + i2 += n8; + i3 += n8; + i4 += n8; + + //sumdiff(x[i3], x[i4], t1, t2); // {s, d} <--| {a+b, a-b} + t1 = x[i3] + x[i4]; + t2 = x[i3] - x[i4]; + + t1 = -t1 * Math.SQRT1_2; + t2 *= Math.SQRT1_2; + + // sumdiff(t1, x[i2], x[i4], x[i3]); // {s, d} <--| {a+b, a-b} + st1 = x[i2]; + x[i4] = t1 + st1; + x[i3] = t1 - st1; + + //sumdiff3(x[i1], t2, x[i2]); // {a, b, d} <--| {a+b, b, a-b} + x[i2] = x[i1] - t2; + x[i1] += t2; + } + } else { + for(i0 = ix; i0 < n; i0 += id) { + i1 = i0; + i2 = i1 + n4; + i3 = i2 + n4; + i4 = i3 + n4; + + //diffsum3_r(x[i3], x[i4], t1); // {a, b, s} <--| {a, b-a, a+b} + t1 = x[i3] + x[i4]; + x[i4] -= x[i3]; + + //sumdiff3(x[i1], t1, x[i3]); // {a, b, d} <--| {a+b, b, a-b} + x[i3] = x[i1] - t1; + x[i1] += t1; + } + } + + ix = (id << 1) - n2; + id = id << 2; + } while (ix < n); + + e = TWO_PI / n2; + + for (var j = 1; j < n8; j++) { + a = j * e; + ss1 = Math.sin(a); + cc1 = Math.cos(a); + + //ss3 = sin(3*a); cc3 = cos(3*a); + cc3 = 4*cc1*(cc1*cc1-0.75); + ss3 = 4*ss1*(0.75-ss1*ss1); + + ix = 0; id = n2 << 1; + do { + for (i0 = ix; i0 < n; i0 += id) { + i1 = i0 + j; + i2 = i1 + n4; + i3 = i2 + n4; + i4 = i3 + n4; + + i5 = i0 + n4 - j; + i6 = i5 + n4; + i7 = i6 + n4; + i8 = i7 + n4; + + //cmult(c, s, x, y, &u, &v) + //cmult(cc1, ss1, x[i7], x[i3], t2, t1); // {u,v} <--| {x*c-y*s, x*s+y*c} + t2 = x[i7]*cc1 - x[i3]*ss1; + t1 = x[i7]*ss1 + x[i3]*cc1; + + //cmult(cc3, ss3, x[i8], x[i4], t4, t3); + t4 = x[i8]*cc3 - x[i4]*ss3; + t3 = x[i8]*ss3 + x[i4]*cc3; + + //sumdiff(t2, t4); // {a, b} <--| {a+b, a-b} + st1 = t2 - t4; + t2 += t4; + t4 = st1; + + //sumdiff(t2, x[i6], x[i8], x[i3]); // {s, d} <--| {a+b, a-b} + //st1 = x[i6]; x[i8] = t2 + st1; x[i3] = t2 - st1; + x[i8] = t2 + x[i6]; + x[i3] = t2 - x[i6]; + + //sumdiff_r(t1, t3); // {a, b} <--| {a+b, b-a} + st1 = t3 - t1; + t1 += t3; + t3 = st1; + + //sumdiff(t3, x[i2], x[i4], x[i7]); // {s, d} <--| {a+b, a-b} + //st1 = x[i2]; x[i4] = t3 + st1; x[i7] = t3 - st1; + x[i4] = t3 + x[i2]; + x[i7] = t3 - x[i2]; + + //sumdiff3(x[i1], t1, x[i6]); // {a, b, d} <--| {a+b, b, a-b} + x[i6] = x[i1] - t1; + x[i1] += t1; + + //diffsum3_r(t4, x[i5], x[i2]); // {a, b, s} <--| {a, b-a, a+b} + x[i2] = t4 + x[i5]; + x[i5] -= t4; + } + + ix = (id << 1) - n2; + id = id << 2; + + } while (ix < n); + } + } + + while (--i) { + rval = x[i]; + ival = x[n-i-1]; + mag = bSi * sqrt(rval * rval + ival * ival); + + if (mag > this.peak) { + this.peakBand = i; + this.peak = mag; + } + + spectrum[i] = mag; + } + + spectrum[0] = bSi * x[0]; + + return spectrum; +}; + +function Sampler(file, bufferSize, sampleRate, playStart, playEnd, loopStart, loopEnd, loopMode) { + this.file = file; + this.bufferSize = bufferSize; + this.sampleRate = sampleRate; + this.playStart = playStart || 0; // 0% + this.playEnd = playEnd || 1; // 100% + this.loopStart = loopStart || 0; + this.loopEnd = loopEnd || 1; + this.loopMode = loopMode || DSP.OFF; + this.loaded = false; + this.samples = []; + this.signal = new Float64Array(bufferSize); + this.frameCount = 0; + this.envelope = null; + this.amplitude = 1; + this.rootFrequency = 110; // A2 110 + this.frequency = 550; + this.step = this.frequency / this.rootFrequency; + this.duration = 0; + this.samplesProcessed = 0; + this.playhead = 0; + + var audio = /* new Audio();*/ document.createElement("AUDIO"); + var self = this; + + this.loadSamples = function(event) { + var buffer = DSP.getChannel(DSP.MIX, event.frameBuffer); + for ( var i = 0; i < buffer.length; i++) { + self.samples.push(buffer[i]); + } + }; + + this.loadComplete = function() { + // convert flexible js array into a fast typed array + self.samples = new Float64Array(self.samples); + self.loaded = true; + }; + + this.loadMetaData = function() { + self.duration = audio.duration; + }; + + audio.addEventListener("MozAudioAvailable", this.loadSamples, false); + audio.addEventListener("loadedmetadata", this.loadMetaData, false); + audio.addEventListener("ended", this.loadComplete, false); + audio.muted = true; + audio.src = file; + audio.play(); +} + +Sampler.prototype.applyEnvelope = function() { + this.envelope.process(this.signal); + return this.signal; +}; + +Sampler.prototype.generate = function() { + var frameOffset = this.frameCount * this.bufferSize; + + var loopWidth = this.playEnd * this.samples.length - this.playStart * this.samples.length; + var playStartSamples = this.playStart * this.samples.length; // ie 0.5 -> 50% of the length + var playEndSamples = this.playEnd * this.samples.length; // ie 0.5 -> 50% of the length + var offset; + + for ( var i = 0; i < this.bufferSize; i++ ) { + switch (this.loopMode) { + case DSP.OFF: + this.playhead = Math.round(this.samplesProcessed * this.step + playStartSamples); + if (this.playhead < (this.playEnd * this.samples.length) ) { + this.signal[i] = this.samples[this.playhead] * this.amplitude; + } else { + this.signal[i] = 0; + } + break; + + case DSP.FW: + this.playhead = Math.round((this.samplesProcessed * this.step) % loopWidth + playStartSamples); + if (this.playhead < (this.playEnd * this.samples.length) ) { + this.signal[i] = this.samples[this.playhead] * this.amplitude; + } + break; + + case DSP.BW: + this.playhead = playEndSamples - Math.round((this.samplesProcessed * this.step) % loopWidth); + if (this.playhead < (this.playEnd * this.samples.length) ) { + this.signal[i] = this.samples[this.playhead] * this.amplitude; + } + break; + + case DSP.FWBW: + if ( Math.floor(this.samplesProcessed * this.step / loopWidth) % 2 === 0 ) { + this.playhead = Math.round((this.samplesProcessed * this.step) % loopWidth + playStartSamples); + } else { + this.playhead = playEndSamples - Math.round((this.samplesProcessed * this.step) % loopWidth); + } + if (this.playhead < (this.playEnd * this.samples.length) ) { + this.signal[i] = this.samples[this.playhead] * this.amplitude; + } + break; + } + this.samplesProcessed++; + } + + this.frameCount++; + + return this.signal; +}; + +Sampler.prototype.setFreq = function(frequency) { + var totalProcessed = this.samplesProcessed * this.step; + this.frequency = frequency; + this.step = this.frequency / this.rootFrequency; + this.samplesProcessed = Math.round(totalProcessed/this.step); +}; + +Sampler.prototype.reset = function() { + this.samplesProcessed = 0; + this.playhead = 0; +}; + +/** + * Oscillator class for generating and modifying signals + * + * @param {Number} type A waveform constant (eg. DSP.SINE) + * @param {Number} frequency Initial frequency of the signal + * @param {Number} amplitude Initial amplitude of the signal + * @param {Number} bufferSize Size of the sample buffer to generate + * @param {Number} sampleRate The sample rate of the signal + * + * @contructor + */ +function Oscillator(type, frequency, amplitude, bufferSize, sampleRate) { + this.frequency = frequency; + this.amplitude = amplitude; + this.bufferSize = bufferSize; + this.sampleRate = sampleRate; + //this.pulseWidth = pulseWidth; + this.frameCount = 0; + + this.waveTableLength = 2048; + + this.cyclesPerSample = frequency / sampleRate; + + this.signal = new Float64Array(bufferSize); + this.envelope = null; + + switch(parseInt(type, 10)) { + case DSP.TRIANGLE: + this.func = Oscillator.Triangle; + break; + + case DSP.SAW: + this.func = Oscillator.Saw; + break; + + case DSP.SQUARE: + this.func = Oscillator.Square; + break; + + default: + case DSP.SINE: + this.func = Oscillator.Sine; + break; + } + + this.generateWaveTable = function() { + Oscillator.waveTable[this.func] = new Float64Array(2048); + var waveTableTime = this.waveTableLength / this.sampleRate; + var waveTableHz = 1 / waveTableTime; + + for (var i = 0; i < this.waveTableLength; i++) { + Oscillator.waveTable[this.func][i] = this.func(i * waveTableHz/this.sampleRate); + } + }; + + if ( typeof Oscillator.waveTable === 'undefined' ) { + Oscillator.waveTable = {}; + } + + if ( typeof Oscillator.waveTable[this.func] === 'undefined' ) { + this.generateWaveTable(); + } + + this.waveTable = Oscillator.waveTable[this.func]; +} + +/** + * Set the amplitude of the signal + * + * @param {Number} amplitude The amplitude of the signal (between 0 and 1) + */ +Oscillator.prototype.setAmp = function(amplitude) { + if (amplitude >= 0 && amplitude <= 1) { + this.amplitude = amplitude; + } else { + throw "Amplitude out of range (0..1)."; + } +}; + +/** + * Set the frequency of the signal + * + * @param {Number} frequency The frequency of the signal + */ +Oscillator.prototype.setFreq = function(frequency) { + this.frequency = frequency; + this.cyclesPerSample = frequency / this.sampleRate; +}; + +// Add an oscillator +Oscillator.prototype.add = function(oscillator) { + for ( var i = 0; i < this.bufferSize; i++ ) { + //this.signal[i] += oscillator.valueAt(i); + this.signal[i] += oscillator.signal[i]; + } + + return this.signal; +}; + +// Add a signal to the current generated osc signal +Oscillator.prototype.addSignal = function(signal) { + for ( var i = 0; i < signal.length; i++ ) { + if ( i >= this.bufferSize ) { + break; + } + this.signal[i] += signal[i]; + + /* + // Constrain amplitude + if ( this.signal[i] > 1 ) { + this.signal[i] = 1; + } else if ( this.signal[i] < -1 ) { + this.signal[i] = -1; + } + */ + } + return this.signal; +}; + +// Add an envelope to the oscillator +Oscillator.prototype.addEnvelope = function(envelope) { + this.envelope = envelope; +}; + +Oscillator.prototype.applyEnvelope = function() { + this.envelope.process(this.signal); +}; + +Oscillator.prototype.valueAt = function(offset) { + return this.waveTable[offset % this.waveTableLength]; +}; + +Oscillator.prototype.generate = function() { + var frameOffset = this.frameCount * this.bufferSize; + var step = this.waveTableLength * this.frequency / this.sampleRate; + var offset; + + for ( var i = 0; i < this.bufferSize; i++ ) { + //var step = (frameOffset + i) * this.cyclesPerSample % 1; + //this.signal[i] = this.func(step) * this.amplitude; + //this.signal[i] = this.valueAt(Math.round((frameOffset + i) * step)) * this.amplitude; + offset = Math.round((frameOffset + i) * step); + this.signal[i] = this.waveTable[offset % this.waveTableLength] * this.amplitude; + } + + this.frameCount++; + + return this.signal; +}; + +Oscillator.Sine = function(step) { + return Math.sin(DSP.TWO_PI * step); +}; + +Oscillator.Square = function(step) { + return step < 0.5 ? 1 : -1; +}; + +Oscillator.Saw = function(step) { + return 2 * (step - Math.round(step)); +}; + +Oscillator.Triangle = function(step) { + return 1 - 4 * Math.abs(Math.round(step) - step); +}; + +Oscillator.Pulse = function(step) { + // stub +}; + +function ADSR(attackLength, decayLength, sustainLevel, sustainLength, releaseLength, sampleRate) { + this.sampleRate = sampleRate; + // Length in seconds + this.attackLength = attackLength; + this.decayLength = decayLength; + this.sustainLevel = sustainLevel; + this.sustainLength = sustainLength; + this.releaseLength = releaseLength; + this.sampleRate = sampleRate; + + // Length in samples + this.attackSamples = attackLength * sampleRate; + this.decaySamples = decayLength * sampleRate; + this.sustainSamples = sustainLength * sampleRate; + this.releaseSamples = releaseLength * sampleRate; + + // Updates the envelope sample positions + this.update = function() { + this.attack = this.attackSamples; + this.decay = this.attack + this.decaySamples; + this.sustain = this.decay + this.sustainSamples; + this.release = this.sustain + this.releaseSamples; + }; + + this.update(); + + this.samplesProcessed = 0; +} + +ADSR.prototype.noteOn = function() { + this.samplesProcessed = 0; + this.sustainSamples = this.sustainLength * this.sampleRate; + this.update(); +}; + +// Send a note off when using a sustain of infinity to let the envelope enter the release phase +ADSR.prototype.noteOff = function() { + this.sustainSamples = this.samplesProcessed - this.decaySamples; + this.update(); +}; + +ADSR.prototype.processSample = function(sample) { + var amplitude = 0; + + if ( this.samplesProcessed <= this.attack ) { + amplitude = 0 + (1 - 0) * ((this.samplesProcessed - 0) / (this.attack - 0)); + } else if ( this.samplesProcessed > this.attack && this.samplesProcessed <= this.decay ) { + amplitude = 1 + (this.sustainLevel - 1) * ((this.samplesProcessed - this.attack) / (this.decay - this.attack)); + } else if ( this.samplesProcessed > this.decay && this.samplesProcessed <= this.sustain ) { + amplitude = this.sustainLevel; + } else if ( this.samplesProcessed > this.sustain && this.samplesProcessed <= this.release ) { + amplitude = this.sustainLevel + (0 - this.sustainLevel) * ((this.samplesProcessed - this.sustain) / (this.release - this.sustain)); + } + + return sample * amplitude; +}; + +ADSR.prototype.value = function() { + var amplitude = 0; + + if ( this.samplesProcessed <= this.attack ) { + amplitude = 0 + (1 - 0) * ((this.samplesProcessed - 0) / (this.attack - 0)); + } else if ( this.samplesProcessed > this.attack && this.samplesProcessed <= this.decay ) { + amplitude = 1 + (this.sustainLevel - 1) * ((this.samplesProcessed - this.attack) / (this.decay - this.attack)); + } else if ( this.samplesProcessed > this.decay && this.samplesProcessed <= this.sustain ) { + amplitude = this.sustainLevel; + } else if ( this.samplesProcessed > this.sustain && this.samplesProcessed <= this.release ) { + amplitude = this.sustainLevel + (0 - this.sustainLevel) * ((this.samplesProcessed - this.sustain) / (this.release - this.sustain)); + } + + return amplitude; +}; + +ADSR.prototype.process = function(buffer) { + for ( var i = 0; i < buffer.length; i++ ) { + buffer[i] *= this.value(); + + this.samplesProcessed++; + } + + return buffer; +}; + + +ADSR.prototype.isActive = function() { + if ( this.samplesProcessed > this.release || this.samplesProcessed === -1 ) { + return false; + } else { + return true; + } +}; + +ADSR.prototype.disable = function() { + this.samplesProcessed = -1; +}; + +function IIRFilter(type, cutoff, resonance, sampleRate) { + this.sampleRate = sampleRate; + + switch(type) { + case DSP.LOWPASS: + case DSP.LP12: + this.func = new IIRFilter.LP12(cutoff, resonance, sampleRate); + break; + } +} + +IIRFilter.prototype.__defineGetter__('cutoff', + function() { + return this.func.cutoff; + } +); + +IIRFilter.prototype.__defineGetter__('resonance', + function() { + return this.func.resonance; + } +); + +IIRFilter.prototype.set = function(cutoff, resonance) { + this.func.calcCoeff(cutoff, resonance); +}; + +IIRFilter.prototype.process = function(buffer) { + this.func.process(buffer); +}; + +// Add an envelope to the filter +IIRFilter.prototype.addEnvelope = function(envelope) { + if ( envelope instanceof ADSR ) { + this.func.addEnvelope(envelope); + } else { + throw "Not an envelope."; + } +}; + +IIRFilter.LP12 = function(cutoff, resonance, sampleRate) { + this.sampleRate = sampleRate; + this.vibraPos = 0; + this.vibraSpeed = 0; + this.envelope = false; + + this.calcCoeff = function(cutoff, resonance) { + this.w = 2.0 * Math.PI * cutoff / this.sampleRate; + this.q = 1.0 - this.w / (2.0 * (resonance + 0.5 / (1.0 + this.w)) + this.w - 2.0); + this.r = this.q * this.q; + this.c = this.r + 1.0 - 2.0 * Math.cos(this.w) * this.q; + + this.cutoff = cutoff; + this.resonance = resonance; + }; + + this.calcCoeff(cutoff, resonance); + + this.process = function(buffer) { + for ( var i = 0; i < buffer.length; i++ ) { + this.vibraSpeed += (buffer[i] - this.vibraPos) * this.c; + this.vibraPos += this.vibraSpeed; + this.vibraSpeed *= this.r; + + /* + var temp = this.vibraPos; + + if ( temp > 1.0 ) { + temp = 1.0; + } else if ( temp < -1.0 ) { + temp = -1.0; + } else if ( temp != temp ) { + temp = 1; + } + + buffer[i] = temp; + */ + + if (this.envelope) { + buffer[i] = (buffer[i] * (1 - this.envelope.value())) + (this.vibraPos * this.envelope.value()); + this.envelope.samplesProcessed++; + } else { + buffer[i] = this.vibraPos; + } + } + }; +}; + +IIRFilter.LP12.prototype.addEnvelope = function(envelope) { + this.envelope = envelope; +}; + +function IIRFilter2(type, cutoff, resonance, sampleRate) { + this.type = type; + this.cutoff = cutoff; + this.resonance = resonance; + this.sampleRate = sampleRate; + + this.f = Float64Array(4); + this.f[0] = 0.0; // lp + this.f[1] = 0.0; // hp + this.f[2] = 0.0; // bp + this.f[3] = 0.0; // br + + this.calcCoeff = function(cutoff, resonance) { + this.freq = 2 * Math.sin(Math.PI * Math.min(0.25, cutoff/(this.sampleRate*2))); + this.damp = Math.min(2 * (1 - Math.pow(resonance, 0.25)), Math.min(2, 2/this.freq - this.freq * 0.5)); + }; + + this.calcCoeff(cutoff, resonance); +} + +IIRFilter2.prototype.process = function(buffer) { + var input, output; + var f = this.f; + + for ( var i = 0; i < buffer.length; i++ ) { + input = buffer[i]; + + // first pass + f[3] = input - this.damp * f[2]; + f[0] = f[0] + this.freq * f[2]; + f[1] = f[3] - f[0]; + f[2] = this.freq * f[1] + f[2]; + output = 0.5 * f[this.type]; + + // second pass + f[3] = input - this.damp * f[2]; + f[0] = f[0] + this.freq * f[2]; + f[1] = f[3] - f[0]; + f[2] = this.freq * f[1] + f[2]; + output += 0.5 * f[this.type]; + + if (this.envelope) { + buffer[i] = (buffer[i] * (1 - this.envelope.value())) + (output * this.envelope.value()); + this.envelope.samplesProcessed++; + } else { + buffer[i] = output; + } + } +}; + +IIRFilter2.prototype.addEnvelope = function(envelope) { + if ( envelope instanceof ADSR ) { + this.envelope = envelope; + } else { + throw "This is not an envelope."; + } +}; + +IIRFilter2.prototype.set = function(cutoff, resonance) { + this.calcCoeff(cutoff, resonance); +}; + + + +function WindowFunction(type, alpha) { + this.alpha = alpha; + + switch(type) { + case DSP.BARTLETT: + this.func = WindowFunction.Bartlett; + break; + + case DSP.BARTLETTHANN: + this.func = WindowFunction.BartlettHann; + break; + + case DSP.BLACKMAN: + this.func = WindowFunction.Blackman; + this.alpha = this.alpha || 0.16; + break; + + case DSP.COSINE: + this.func = WindowFunction.Cosine; + break; + + case DSP.GAUSS: + this.func = WindowFunction.Gauss; + this.alpha = this.alpha || 0.25; + break; + + case DSP.HAMMING: + this.func = WindowFunction.Hamming; + break; + + case DSP.HANN: + this.func = WindowFunction.Hann; + break; + + case DSP.LANCZOS: + this.func = WindowFunction.Lanczoz; + break; + + case DSP.RECTANGULAR: + this.func = WindowFunction.Rectangular; + break; + + case DSP.TRIANGULAR: + this.func = WindowFunction.Triangular; + break; + } +} + +WindowFunction.prototype.process = function(buffer) { + var length = buffer.length; + for ( var i = 0; i < length; i++ ) { + buffer[i] *= this.func(length, i, this.alpha); + } + return buffer; +}; + +WindowFunction.Bartlett = function(length, index) { + return 2 / (length - 1) * ((length - 1) / 2 - Math.abs(index - (length - 1) / 2)); +}; + +WindowFunction.BartlettHann = function(length, index) { + return 0.62 - 0.48 * Math.abs(index / (length - 1) - 0.5) - 0.38 * Math.cos(DSP.TWO_PI * index / (length - 1)); +}; + +WindowFunction.Blackman = function(length, index, alpha) { + var a0 = (1 - alpha) / 2; + var a1 = 0.5; + var a2 = alpha / 2; + + return a0 - a1 * Math.cos(DSP.TWO_PI * index / (length - 1)) + a2 * Math.cos(4 * Math.PI * index / (length - 1)); +}; + +WindowFunction.Cosine = function(length, index) { + return Math.cos(Math.PI * index / (length - 1) - Math.PI / 2); +}; + +WindowFunction.Gauss = function(length, index, alpha) { + return Math.pow(Math.E, -0.5 * Math.pow((index - (length - 1) / 2) / (alpha * (length - 1) / 2), 2)); +}; + +WindowFunction.Hamming = function(length, index) { + return 0.54 - 0.46 * Math.cos(DSP.TWO_PI * index / (length - 1)); +}; + +WindowFunction.Hann = function(length, index) { + return 0.5 * (1 - Math.cos(DSP.TWO_PI * index / (length - 1))); +}; + +WindowFunction.Lanczos = function(length, index) { + var x = 2 * index / (length - 1) - 1; + return Math.sin(Math.PI * x) / (Math.PI * x); +}; + +WindowFunction.Rectangular = function(length, index) { + return 1; +}; + +WindowFunction.Triangular = function(length, index) { + return 2 / length * (length / 2 - Math.abs(index - (length - 1) / 2)); +}; + +function sinh (arg) { + // Returns the hyperbolic sine of the number, defined as (exp(number) - exp(-number))/2 + // + // version: 1004.2314 + // discuss at: http://phpjs.org/functions/sinh // + original by: Onno Marsman + // * example 1: sinh(-0.9834330348825909); + // * returns 1: -1.1497971402636502 + return (Math.exp(arg) - Math.exp(-arg))/2; +} + +/* + * Biquad filter + * + * Created by Ricard Marxer on 2010-05-23. + * Copyright 2010 Ricard Marxer. All rights reserved. + * + */ +// Implementation based on: +// http://www.musicdsp.org/files/Audio-EQ-Cookbook.txt +function Biquad(type, sampleRate) { + this.Fs = sampleRate; + this.type = type; // type of the filter + this.parameterType = DSP.Q; // type of the parameter + + this.x_1_l = 0; + this.x_2_l = 0; + this.y_1_l = 0; + this.y_2_l = 0; + + this.x_1_r = 0; + this.x_2_r = 0; + this.y_1_r = 0; + this.y_2_r = 0; + + this.b0 = 1; + this.a0 = 1; + + this.b1 = 0; + this.a1 = 0; + + this.b2 = 0; + this.a2 = 0; + + this.b0a0 = this.b0 / this.a0; + this.b1a0 = this.b1 / this.a0; + this.b2a0 = this.b2 / this.a0; + this.a1a0 = this.a1 / this.a0; + this.a2a0 = this.a2 / this.a0; + + this.f0 = 3000; // "wherever it's happenin', man." Center Frequency or + // Corner Frequency, or shelf midpoint frequency, depending + // on which filter type. The "significant frequency". + + this.dBgain = 12; // used only for peaking and shelving filters + + this.Q = 1; // the EE kind of definition, except for peakingEQ in which A*Q is + // the classic EE Q. That adjustment in definition was made so that + // a boost of N dB followed by a cut of N dB for identical Q and + // f0/Fs results in a precisely flat unity gain filter or "wire". + + this.BW = -3; // the bandwidth in octaves (between -3 dB frequencies for BPF + // and notch or between midpoint (dBgain/2) gain frequencies for + // peaking EQ + + this.S = 1; // a "shelf slope" parameter (for shelving EQ only). When S = 1, + // the shelf slope is as steep as it can be and remain monotonically + // increasing or decreasing gain with frequency. The shelf slope, in + // dB/octave, remains proportional to S for all other values for a + // fixed f0/Fs and dBgain. + + this.coefficients = function() { + var b = [this.b0, this.b1, this.b2]; + var a = [this.a0, this.a1, this.a2]; + return {b: b, a:a}; + }; + + this.setFilterType = function(type) { + this.type = type; + this.recalculateCoefficients(); + }; + + this.setSampleRate = function(rate) { + this.Fs = rate; + this.recalculateCoefficients(); + }; + + this.setQ = function(q) { + this.parameterType = DSP.Q; + this.Q = Math.max(Math.min(q, 115.0), 0.001); + this.recalculateCoefficients(); + }; + + this.setBW = function(bw) { + this.parameterType = DSP.BW; + this.BW = bw; + this.recalculateCoefficients(); + }; + + this.setS = function(s) { + this.parameterType = DSP.S; + this.S = Math.max(Math.min(s, 5.0), 0.0001); + this.recalculateCoefficients(); + }; + + this.setF0 = function(freq) { + this.f0 = freq; + this.recalculateCoefficients(); + }; + + this.setDbGain = function(g) { + this.dBgain = g; + this.recalculateCoefficients(); + }; + + this.recalculateCoefficients = function() { + var A; + if (type === DSP.PEAKING_EQ || type === DSP.LOW_SHELF || type === DSP.HIGH_SHELF ) { + A = Math.pow(10, (this.dBgain/40)); // for peaking and shelving EQ filters only + } else { + A = Math.sqrt( Math.pow(10, (this.dBgain/20)) ); + } + + var w0 = DSP.TWO_PI * this.f0 / this.Fs; + + var cosw0 = Math.cos(w0); + var sinw0 = Math.sin(w0); + + var alpha = 0; + + switch (this.parameterType) { + case DSP.Q: + alpha = sinw0/(2*this.Q); + break; + + case DSP.BW: + alpha = sinw0 * sinh( Math.LN2/2 * this.BW * w0/sinw0 ); + break; + + case DSP.S: + alpha = sinw0/2 * Math.sqrt( (A + 1/A)*(1/this.S - 1) + 2 ); + break; + } + + /** + FYI: The relationship between bandwidth and Q is + 1/Q = 2*sinh(ln(2)/2*BW*w0/sin(w0)) (digital filter w BLT) + or 1/Q = 2*sinh(ln(2)/2*BW) (analog filter prototype) + + The relationship between shelf slope and Q is + 1/Q = sqrt((A + 1/A)*(1/S - 1) + 2) + */ + + var coeff; + + switch (this.type) { + case DSP.LPF: // H(s) = 1 / (s^2 + s/Q + 1) + this.b0 = (1 - cosw0)/2; + this.b1 = 1 - cosw0; + this.b2 = (1 - cosw0)/2; + this.a0 = 1 + alpha; + this.a1 = -2 * cosw0; + this.a2 = 1 - alpha; + break; + + case DSP.HPF: // H(s) = s^2 / (s^2 + s/Q + 1) + this.b0 = (1 + cosw0)/2; + this.b1 = -(1 + cosw0); + this.b2 = (1 + cosw0)/2; + this.a0 = 1 + alpha; + this.a1 = -2 * cosw0; + this.a2 = 1 - alpha; + break; + + case DSP.BPF_CONSTANT_SKIRT: // H(s) = s / (s^2 + s/Q + 1) (constant skirt gain, peak gain = Q) + this.b0 = sinw0/2; + this.b1 = 0; + this.b2 = -sinw0/2; + this.a0 = 1 + alpha; + this.a1 = -2*cosw0; + this.a2 = 1 - alpha; + break; + + case DSP.BPF_CONSTANT_PEAK: // H(s) = (s/Q) / (s^2 + s/Q + 1) (constant 0 dB peak gain) + this.b0 = alpha; + this.b1 = 0; + this.b2 = -alpha; + this.a0 = 1 + alpha; + this.a1 = -2*cosw0; + this.a2 = 1 - alpha; + break; + + case DSP.NOTCH: // H(s) = (s^2 + 1) / (s^2 + s/Q + 1) + this.b0 = 1; + this.b1 = -2*cosw0; + this.b2 = 1; + this.a0 = 1 + alpha; + this.a1 = -2*cosw0; + this.a2 = 1 - alpha; + break; + + case DSP.APF: // H(s) = (s^2 - s/Q + 1) / (s^2 + s/Q + 1) + this.b0 = 1 - alpha; + this.b1 = -2*cosw0; + this.b2 = 1 + alpha; + this.a0 = 1 + alpha; + this.a1 = -2*cosw0; + this.a2 = 1 - alpha; + break; + + case DSP.PEAKING_EQ: // H(s) = (s^2 + s*(A/Q) + 1) / (s^2 + s/(A*Q) + 1) + this.b0 = 1 + alpha*A; + this.b1 = -2*cosw0; + this.b2 = 1 - alpha*A; + this.a0 = 1 + alpha/A; + this.a1 = -2*cosw0; + this.a2 = 1 - alpha/A; + break; + + case DSP.LOW_SHELF: // H(s) = A * (s^2 + (sqrt(A)/Q)*s + A)/(A*s^2 + (sqrt(A)/Q)*s + 1) + coeff = sinw0 * Math.sqrt( (A^2 + 1)*(1/this.S - 1) + 2*A ); + this.b0 = A*((A+1) - (A-1)*cosw0 + coeff); + this.b1 = 2*A*((A-1) - (A+1)*cosw0); + this.b2 = A*((A+1) - (A-1)*cosw0 - coeff); + this.a0 = (A+1) + (A-1)*cosw0 + coeff; + this.a1 = -2*((A-1) + (A+1)*cosw0); + this.a2 = (A+1) + (A-1)*cosw0 - coeff; + break; + + case DSP.HIGH_SHELF: // H(s) = A * (A*s^2 + (sqrt(A)/Q)*s + 1)/(s^2 + (sqrt(A)/Q)*s + A) + coeff = sinw0 * Math.sqrt( (A^2 + 1)*(1/this.S - 1) + 2*A ); + this.b0 = A*((A+1) + (A-1)*cosw0 + coeff); + this.b1 = -2*A*((A-1) + (A+1)*cosw0); + this.b2 = A*((A+1) + (A-1)*cosw0 - coeff); + this.a0 = (A+1) - (A-1)*cosw0 + coeff; + this.a1 = 2*((A-1) - (A+1)*cosw0); + this.a2 = (A+1) - (A-1)*cosw0 - coeff; + break; + } + + this.b0a0 = this.b0/this.a0; + this.b1a0 = this.b1/this.a0; + this.b2a0 = this.b2/this.a0; + this.a1a0 = this.a1/this.a0; + this.a2a0 = this.a2/this.a0; + }; + + this.process = function(buffer) { + //y[n] = (b0/a0)*x[n] + (b1/a0)*x[n-1] + (b2/a0)*x[n-2] + // - (a1/a0)*y[n-1] - (a2/a0)*y[n-2] + + var len = buffer.length; + var output = new Float64Array(len); + + for ( var i=0; i on 2010-05-23. + * Copyright 2010 Ricard Marxer. All rights reserved. + * + * @buffer array of magnitudes to convert to decibels + * + * @returns the array in decibels + * + */ +DSP.mag2db = function(buffer) { + var minDb = -120; + var minMag = Math.pow(10.0, minDb / 20.0); + + var log = Math.log; + var max = Math.max; + + var result = Float64Array(buffer.length); + for (var i=0; i on 2010-05-23. + * Copyright 2010 Ricard Marxer. All rights reserved. + * + * Calculates the frequency response at the given points. + * + * @b b coefficients of the filter + * @a a coefficients of the filter + * @w w points (normally between -PI and PI) where to calculate the frequency response + * + * @returns the frequency response in magnitude + * + */ +DSP.freqz = function(b, a, w) { + var i, j; + + if (!w) { + w = Float64Array(200); + for (i=0;i on 2010-05-23. + * Copyright 2010 Ricard Marxer. All rights reserved. + * + */ +function GraphicalEq(sampleRate) { + this.FS = sampleRate; + this.minFreq = 40.0; + this.maxFreq = 16000.0; + + this.bandsPerOctave = 1.0; + + this.filters = []; + this.freqzs = []; + + this.calculateFreqzs = true; + + this.recalculateFilters = function() { + var bandCount = Math.round(Math.log(this.maxFreq/this.minFreq) * this.bandsPerOctave/ Math.LN2); + + this.filters = []; + for (var i=0; i (this.filters.length-1)) { + throw "The band index of the graphical equalizer is out of bounds."; + } + + if (!gain) { + throw "A gain must be passed."; + } + + this.filters[bandIndex].setDbGain(gain); + this.recalculateFreqz(bandIndex); + }; + + this.recalculateFreqz = function(bandIndex) { + if (!this.calculateFreqzs) { + return; + } + + if (bandIndex < 0 || bandIndex > (this.filters.length-1)) { + throw "The band index of the graphical equalizer is out of bounds. " + bandIndex + " is out of [" + 0 + ", " + this.filters.length-1 + "]"; + } + + if (!this.w) { + this.w = Float64Array(400); + for (var i=0; i1.0 (amplify) + * @param {Number} delayVolume Initial feedback delay volume. Float value: 0.0 (silence), 1.0 (normal), >1.0 (amplify) + * + * @constructor + */ +function MultiDelay(maxDelayInSamplesSize, delayInSamples, masterVolume, delayVolume) { + this.delayBufferSamples = new Float64Array(maxDelayInSamplesSize); // The maximum size of delay + this.delayInputPointer = delayInSamples; + this.delayOutputPointer = 0; + + this.delayInSamples = delayInSamples; + this.masterVolume = masterVolume; + this.delayVolume = delayVolume; +} + +/** + * Change the delay time in samples. + * + * @param {Number} delayInSamples Delay in samples + */ +MultiDelay.prototype.setDelayInSamples = function (delayInSamples) { + this.delayInSamples = delayInSamples; + + this.delayInputPointer = this.delayOutputPointer + delayInSamples; + + if (this.delayInputPointer >= this.delayBufferSamples.length-1) { + this.delayInputPointer = this.delayInputPointer - this.delayBufferSamples.length; + } +}; + +/** + * Change the master volume. + * + * @param {Number} masterVolume Float value: 0.0 (silence), 1.0 (normal), >1.0 (amplify) + */ +MultiDelay.prototype.setMasterVolume = function(masterVolume) { + this.masterVolume = masterVolume; +}; + +/** + * Change the delay feedback volume. + * + * @param {Number} delayVolume Float value: 0.0 (silence), 1.0 (normal), >1.0 (amplify) + */ +MultiDelay.prototype.setDelayVolume = function(delayVolume) { + this.delayVolume = delayVolume; +}; + +/** + * Process a given interleaved or mono non-interleaved float value Array and adds the delayed audio. + * + * @param {Array} samples Array containing Float values or a Float64Array + * + * @returns A new Float64Array interleaved or mono non-interleaved as was fed to this function. + */ +MultiDelay.prototype.process = function(samples) { + // NB. Make a copy to put in the output samples to return. + var outputSamples = new Float64Array(samples.length); + + for (var i=0; i= this.delayBufferSamples.length-1) { + this.delayInputPointer = 0; + } + + this.delayOutputPointer++; + if (this.delayOutputPointer >= this.delayBufferSamples.length-1) { + this.delayOutputPointer = 0; + } + } + + return outputSamples; +}; + +/** + * SingleDelay effect by Almer Thie (http://code.almeros.com). + * Copyright 2010 Almer Thie. All rights reserved. + * Example: See usage in Reverb class + * + * This is a delay that does NOT feeds it's own delayed signal back into its + * circular buffer, neither does it return the original signal. Also known as + * an AllPassFilter(?). + * + * Compatible with interleaved stereo (or more channel) buffers and + * non-interleaved mono buffers. + * + * @param {Number} maxDelayInSamplesSize Maximum possible delay in samples (size of circular buffer) + * @param {Number} delayInSamples Initial delay in samples + * @param {Number} delayVolume Initial feedback delay volume. Float value: 0.0 (silence), 1.0 (normal), >1.0 (amplify) + * + * @constructor + */ + +function SingleDelay(maxDelayInSamplesSize, delayInSamples, delayVolume) { + this.delayBufferSamples = new Float64Array(maxDelayInSamplesSize); // The maximum size of delay + this.delayInputPointer = delayInSamples; + this.delayOutputPointer = 0; + + this.delayInSamples = delayInSamples; + this.delayVolume = delayVolume; +} + +/** + * Change the delay time in samples. + * + * @param {Number} delayInSamples Delay in samples + */ +SingleDelay.prototype.setDelayInSamples = function(delayInSamples) { + this.delayInSamples = delayInSamples; + this.delayInputPointer = this.delayOutputPointer + delayInSamples; + + if (this.delayInputPointer >= this.delayBufferSamples.length-1) { + this.delayInputPointer = this.delayInputPointer - this.delayBufferSamples.length; + } +}; + +/** + * Change the return signal volume. + * + * @param {Number} delayVolume Float value: 0.0 (silence), 1.0 (normal), >1.0 (amplify) + */ +SingleDelay.prototype.setDelayVolume = function(delayVolume) { + this.delayVolume = delayVolume; +}; + +/** + * Process a given interleaved or mono non-interleaved float value Array and + * returns the delayed audio. + * + * @param {Array} samples Array containing Float values or a Float64Array + * + * @returns A new Float64Array interleaved or mono non-interleaved as was fed to this function. + */ +SingleDelay.prototype.process = function(samples) { + // NB. Make a copy to put in the output samples to return. + var outputSamples = new Float64Array(samples.length); + + for (var i=0; i= this.delayBufferSamples.length-1) { + this.delayInputPointer = 0; + } + + this.delayOutputPointer++; + + if (this.delayOutputPointer >= this.delayBufferSamples.length-1) { + this.delayOutputPointer = 0; + } + } + + return outputSamples; +}; + +/** + * Reverb effect by Almer Thie (http://code.almeros.com). + * Copyright 2010 Almer Thie. All rights reserved. + * Example: http://code.almeros.com/code-examples/reverb-firefox-audio-api/ + * + * This reverb consists of 6 SingleDelays, 6 MultiDelays and an IIRFilter2 + * for each of the two stereo channels. + * + * Compatible with interleaved stereo buffers only! + * + * @param {Number} maxDelayInSamplesSize Maximum possible delay in samples (size of circular buffers) + * @param {Number} delayInSamples Initial delay in samples for internal (Single/Multi)delays + * @param {Number} masterVolume Initial master volume. Float value: 0.0 (silence), 1.0 (normal), >1.0 (amplify) + * @param {Number} mixVolume Initial reverb signal mix volume. Float value: 0.0 (silence), 1.0 (normal), >1.0 (amplify) + * @param {Number} delayVolume Initial feedback delay volume for internal (Single/Multi)delays. Float value: 0.0 (silence), 1.0 (normal), >1.0 (amplify) + * @param {Number} dampFrequency Initial low pass filter frequency. 0 to 44100 (depending on your maximum sampling frequency) + * + * @constructor + */ +function Reverb(maxDelayInSamplesSize, delayInSamples, masterVolume, mixVolume, delayVolume, dampFrequency) { + this.delayInSamples = delayInSamples; + this.masterVolume = masterVolume; + this.mixVolume = mixVolume; + this.delayVolume = delayVolume; + this.dampFrequency = dampFrequency; + + this.NR_OF_MULTIDELAYS = 6; + this.NR_OF_SINGLEDELAYS = 6; + + this.LOWPASSL = new IIRFilter2(DSP.LOWPASS, dampFrequency, 0, 44100); + this.LOWPASSR = new IIRFilter2(DSP.LOWPASS, dampFrequency, 0, 44100); + + this.singleDelays = []; + + var i, delayMultiply; + + for (i = 0; i < this.NR_OF_SINGLEDELAYS; i++) { + delayMultiply = 1.0 + (i/7.0); // 1.0, 1.1, 1.2... + this.singleDelays[i] = new SingleDelay(maxDelayInSamplesSize, Math.round(this.delayInSamples * delayMultiply), this.delayVolume); + } + + this.multiDelays = []; + + for (i = 0; i < this.NR_OF_MULTIDELAYS; i++) { + delayMultiply = 1.0 + (i/10.0); // 1.0, 1.1, 1.2... + this.multiDelays[i] = new MultiDelay(maxDelayInSamplesSize, Math.round(this.delayInSamples * delayMultiply), this.masterVolume, this.delayVolume); + } +} + +/** + * Change the delay time in samples as a base for all delays. + * + * @param {Number} delayInSamples Delay in samples + */ +Reverb.prototype.setDelayInSamples = function (delayInSamples){ + this.delayInSamples = delayInSamples; + + var i, delayMultiply; + + for (i = 0; i < this.NR_OF_SINGLEDELAYS; i++) { + delayMultiply = 1.0 + (i/7.0); // 1.0, 1.1, 1.2... + this.singleDelays[i].setDelayInSamples( Math.round(this.delayInSamples * delayMultiply) ); + } + + for (i = 0; i < this.NR_OF_MULTIDELAYS; i++) { + delayMultiply = 1.0 + (i/10.0); // 1.0, 1.1, 1.2... + this.multiDelays[i].setDelayInSamples( Math.round(this.delayInSamples * delayMultiply) ); + } +}; + +/** + * Change the master volume. + * + * @param {Number} masterVolume Float value: 0.0 (silence), 1.0 (normal), >1.0 (amplify) + */ +Reverb.prototype.setMasterVolume = function (masterVolume){ + this.masterVolume = masterVolume; +}; + +/** + * Change the reverb signal mix level. + * + * @param {Number} mixVolume Float value: 0.0 (silence), 1.0 (normal), >1.0 (amplify) + */ +Reverb.prototype.setMixVolume = function (mixVolume){ + this.mixVolume = mixVolume; +}; + +/** + * Change all delays feedback volume. + * + * @param {Number} delayVolume Float value: 0.0 (silence), 1.0 (normal), >1.0 (amplify) + */ +Reverb.prototype.setDelayVolume = function (delayVolume){ + this.delayVolume = delayVolume; + + var i; + + for (i = 0; i