//XAudioJS realtime audio output compatibility library //Copyright (C) 2010-2015 Grant Galitz //Released to Public Domain var XAudioJSscriptsHandle = document.getElementsByTagName("script"); var XAudioJSsourceHandle = XAudioJSscriptsHandle[XAudioJSscriptsHandle.length-1].src; function XAudioServer(channels, sampleRate, minBufferSize, maxBufferSize, underRunCallback, heartbeatCallback, postheartbeatCallback, volume, failureCallback, userEventLatch) { XAudioJSChannelsAllocated = Math.max(channels, 1); this.XAudioJSSampleRate = Math.abs(sampleRate); XAudioJSMinBufferSize = (minBufferSize >= (XAudioJSSamplesPerCallback * XAudioJSChannelsAllocated) && minBufferSize < maxBufferSize) ? (minBufferSize & (-XAudioJSChannelsAllocated)) : (XAudioJSSamplesPerCallback * XAudioJSChannelsAllocated); XAudioJSMaxBufferSize = (Math.floor(maxBufferSize) > XAudioJSMinBufferSize + XAudioJSChannelsAllocated) ? (maxBufferSize & (-XAudioJSChannelsAllocated)) : (XAudioJSMinBufferSize * XAudioJSChannelsAllocated); this.underRunCallback = (typeof underRunCallback == "function") ? underRunCallback : function () {}; XAudioJSCallbackAPIEventNotificationCallback = (typeof heartbeatCallback == "function") ? heartbeatCallback : null; XAudioJSCallbackAPIEventNotificationCallback2 = (typeof postheartbeatCallback == "function") ? postheartbeatCallback : null; XAudioJSVolume = (volume >= 0 && volume <= 1) ? volume : 1; this.failureCallback = (typeof failureCallback == "function") ? failureCallback : function () { throw(new Error("XAudioJS has encountered a fatal error.")); }; this.userEventLatch = (typeof userEventLatch == "object") ? userEventLatch : null; this.initializeAudio(); } XAudioServer.prototype.MOZWriteAudioNoCallback = function (buffer, upTo) { //Resample before passing to the moz audio api: var bufferLength = Math.min(buffer.length, upTo); for (var bufferIndex = 0; bufferIndex < bufferLength;) { var sliceLength = Math.min(bufferLength - bufferIndex, XAudioJSMaxBufferSize); for (var sliceIndex = 0; sliceIndex < sliceLength; ++sliceIndex) { XAudioJSAudioContextSampleBuffer[sliceIndex] = buffer[bufferIndex++]; } var resampleLength = XAudioJSResampleControl.resampler(sliceIndex); if (resampleLength > 0) { var resampledResult = XAudioJSResampleControl.outputBuffer; var resampledBuffer = XAudioJSGetArraySlice(resampledResult, resampleLength); this.samplesAlreadyWritten += this.audioHandleMoz.mozWriteAudio(resampledBuffer); } } } XAudioServer.prototype.callbackBasedWriteAudioNoCallback = function (buffer, upTo) { //Callback-centered audio APIs: var bufferLength = Math.min(buffer.length, upTo); for (var bufferCounter = 0; bufferCounter < bufferLength && XAudioJSAudioBufferSize < XAudioJSMaxBufferSize;) { XAudioJSAudioContextSampleBuffer[XAudioJSAudioBufferSize++] = buffer[bufferCounter++]; } } /*Pass your samples into here! Pack your samples as a one-dimenional array With the channel samples packed uniformly. examples: mono - [left, left, left, left] stereo - [left, right, left, right, left, right, left, right] */ XAudioServer.prototype.writeAudio = function (buffer, upTo) { switch (this.audioType) { case 0: this.MOZWriteAudioNoCallback(buffer, upTo); this.MOZExecuteCallback(); break; case 2: this.checkFlashInit(); case 1: this.callbackBasedWriteAudioNoCallback(buffer, upTo); this.callbackBasedExecuteCallback(); break; default: this.failureCallback(); } } /*Pass your samples into here if you don't want automatic callback calling: Pack your samples as a one-dimenional array With the channel samples packed uniformly. examples: mono - [left, left, left, left] stereo - [left, right, left, right, left, right, left, right] Useful in preventing infinite recursion issues with calling writeAudio inside your callback. */ XAudioServer.prototype.writeAudioNoCallback = function (buffer, upTo) { switch (this.audioType) { case 0: this.MOZWriteAudioNoCallback(buffer, upTo); break; case 2: this.checkFlashInit(); case 1: this.callbackBasedWriteAudioNoCallback(buffer, upTo); break; default: this.failureCallback(); } } //Developer can use this to see how many samples to write (example: minimum buffer allotment minus remaining samples left returned from this function to make sure maximum buffering is done...) //If null is returned, then that means metric could not be done. XAudioServer.prototype.remainingBuffer = function () { switch (this.audioType) { case 0: return Math.floor((this.samplesAlreadyWritten - this.audioHandleMoz.mozCurrentSampleOffset()) * XAudioJSResampleControl.ratioWeight / XAudioJSChannelsAllocated) * XAudioJSChannelsAllocated; case 2: this.checkFlashInit(); case 1: return (Math.floor((XAudioJSResampledSamplesLeft() * XAudioJSResampleControl.ratioWeight) / XAudioJSChannelsAllocated) * XAudioJSChannelsAllocated) + XAudioJSAudioBufferSize; default: this.failureCallback(); return null; } } XAudioServer.prototype.MOZExecuteCallback = function () { //mozAudio: var samplesRequested = XAudioJSMinBufferSize - this.remainingBuffer(); if (samplesRequested > 0) { var buffer = this.underRunCallback(samplesRequested); this.MOZWriteAudioNoCallback(buffer, buffer.length); } } XAudioServer.prototype.callbackBasedExecuteCallback = function () { //WebKit /Flash Audio: var samplesRequested = XAudioJSMinBufferSize - this.remainingBuffer(); if (samplesRequested > 0) { var buffer = this.underRunCallback(samplesRequested); this.callbackBasedWriteAudioNoCallback(buffer, buffer.length); } } //If you just want your callback called for any possible refill (Execution of callback is still conditional): XAudioServer.prototype.executeCallback = function () { switch (this.audioType) { case 0: this.MOZExecuteCallback(); break; case 2: this.checkFlashInit(); case 1: this.callbackBasedExecuteCallback(); break; default: this.failureCallback(); } } //DO NOT CALL THIS, the lib calls this internally! XAudioServer.prototype.initializeAudio = function () { try { this.initializeMozAudio(); } catch (error) { try { this.initializeWebAudio(); } catch (error) { try { this.initializeFlashAudio(); } catch (error) { this.audioType = -1; this.failureCallback(); } } } } XAudioServer.prototype.initializeMozAudio = function () { this.audioHandleMoz = new Audio(); this.audioHandleMoz.mozSetup(XAudioJSChannelsAllocated, XAudioJSMozAudioSampleRate); this.audioHandleMoz.volume = XAudioJSVolume; this.samplesAlreadyWritten = 0; this.audioType = 0; //if (navigator.platform != "MacIntel" && navigator.platform != "MacPPC") { //Add some additional buffering space to workaround a moz audio api issue: var bufferAmount = (this.XAudioJSSampleRate * XAudioJSChannelsAllocated / 10) | 0; bufferAmount -= bufferAmount % XAudioJSChannelsAllocated; this.samplesAlreadyWritten -= bufferAmount; //} this.initializeResampler(XAudioJSMozAudioSampleRate); } XAudioServer.prototype.initializeWebAudio = function () { if (typeof AudioContext == "undefined" || typeof XAudioJSWebAudioContextHandle == "undefined") { throw null; } else { if (!this.userEventLatch) { this.setupWebAudio(); } else { var parentObj = this; var XAudioJSWebAudioDelayedEvent = 0; this.userEventLatch.addEventListener("click", function () { if (XAudioJSWebAudioDelayedEvent == 0) { parentObj.setupWebAudio(); XAudioJSWebAudioDelayedEvent |= 1; } }, false); this.userEventLatch.addEventListener("touchstart", function () { if (XAudioJSWebAudioDelayedEvent < 2) { parentObj.setupWebAudio(); XAudioJSWebAudioDelayedEvent |= 2; } }, false); this.userEventLatch.addEventListener("touchend", function () { if (XAudioJSWebAudioDelayedEvent < 4) { parentObj.setupWebAudio(); XAudioJSWebAudioDelayedEvent |= 4; } }, false); //TODO: Restructure API to not have to potentially lie to end client about //the samples in buffer before user driven event callback that actually starts WA. this.resetCallbackAPIAudioBuffer(44100); } this.audioType = 1; } } XAudioServer.prototype.setupWebAudio = function () { if (XAudioJSWebAudioLaunchedContext) { XAudioJSWebAudioContextHandle.close(); } try { XAudioJSWebAudioContextHandle = new AudioContext(); //Create a system audio context. } catch (error) { XAudioJSWebAudioContextHandle = new webkitAudioContext(); //Create a system audio context. } XAudioJSWebAudioLaunchedContext = true; if (XAudioJSWebAudioAudioNode) { XAudioJSWebAudioAudioNode.disconnect(); XAudioJSWebAudioAudioNode.onaudioprocess = null; XAudioJSWebAudioAudioNode = null; } try { XAudioJSWebAudioAudioNode = XAudioJSWebAudioContextHandle.createScriptProcessor(XAudioJSSamplesPerCallback, 0, XAudioJSChannelsAllocated); //Create the js event node. } catch (error) { XAudioJSWebAudioAudioNode = XAudioJSWebAudioContextHandle.createJavaScriptNode(XAudioJSSamplesPerCallback, 0, XAudioJSChannelsAllocated); //Create the js event node. } XAudioJSWebAudioAudioNode.onaudioprocess = XAudioJSWebAudioEvent; //Connect the audio processing event to a handling function so we can manipulate output XAudioJSWebAudioAudioNode.connect(XAudioJSWebAudioContextHandle.destination); //Send and chain the output of the audio manipulation to the system audio output. this.resetCallbackAPIAudioBuffer(XAudioJSWebAudioContextHandle.sampleRate); /* Firefox has a bug in its web audio implementation... The node may randomly stop playing on Mac OS X for no good reason. Keep a watchdog timer to restart the failed node if it glitches. Google Chrome never had this issue. */ XAudioJSWebAudioWatchDogLast = (new Date()).getTime(); if (!XAudioJSWebAudioWatchDogTimer && navigator.userAgent.indexOf('Gecko/') > -1) { if (XAudioJSWebAudioWatchDogTimer) { clearInterval(XAudioJSWebAudioWatchDogTimer); } var parentObj = this; XAudioJSWebAudioWatchDogTimer = setInterval(function () { if(typeof XAudioJSWebAudioContextHandle.state != "undefined") { if (XAudioJSWebAudioContextHandle.state === 'suspended') { XAudioJSWebAudioWatchDogLast = (new Date()).getTime(); try { XAudioJSWebAudioContextHandle.resume(); } catch (e) {} } else { var timeDiff = (new Date()).getTime() - XAudioJSWebAudioWatchDogLast; if (timeDiff > 500) { parentObj.setupWebAudio(); } } } }, 500); } } XAudioServer.prototype.initializeFlashAudio = function () { var existingFlashload = document.getElementById("XAudioJS"); this.flashInitialized = false; this.resetCallbackAPIAudioBuffer(44100); switch (XAudioJSChannelsAllocated) { case 1: XAudioJSFlashTransportEncoder = XAudioJSGenerateFlashMonoString; break; case 2: XAudioJSFlashTransportEncoder = XAudioJSGenerateFlashStereoString; break; default: XAudioJSFlashTransportEncoder = XAudioJSGenerateFlashSurroundString; } if (existingFlashload == null) { this.audioHandleFlash = null; var thisObj = this; var mainContainerNode = document.createElement("div"); mainContainerNode.setAttribute("style", "position: fixed; bottom: 0px; right: 0px; margin: 0px; padding: 0px; border: none; width: 8px; height: 8px; overflow: hidden; z-index: -1000; "); var containerNode = document.createElement("div"); containerNode.setAttribute("style", "position: static; border: none; width: 0px; height: 0px; visibility: hidden; margin: 8px; padding: 0px;"); containerNode.setAttribute("id", "XAudioJS"); mainContainerNode.appendChild(containerNode); document.getElementsByTagName("body")[0].appendChild(mainContainerNode); swfobject.embedSWF( XAudioJSsourceHandle.substring(0, XAudioJSsourceHandle.length - 9) + "JS.swf", "XAudioJS", "8", "8", "9.0.0", "", {}, {"allowscriptaccess":"always"}, {"style":"position: static; visibility: hidden; margin: 8px; padding: 0px; border: none"}, function (event) { if (event.success) { thisObj.audioHandleFlash = event.ref; thisObj.checkFlashInit(); } else { thisObj.failureCallback(); thisObj.audioType = -1; } } ); } else { this.audioHandleFlash = existingFlashload; this.checkFlashInit(); } this.audioType = 2; } XAudioServer.prototype.changeVolume = function (newVolume) { if (newVolume >= 0 && newVolume <= 1) { XAudioJSVolume = newVolume; switch (this.audioType) { case 0: this.audioHandleMoz.volume = XAudioJSVolume; case 1: break; case 2: if (this.flashInitialized) { this.audioHandleFlash.changeVolume(XAudioJSVolume); } else { this.checkFlashInit(); } break; default: this.failureCallback(); } } } //Checks to see if the NPAPI Adobe Flash bridge is ready yet: XAudioServer.prototype.checkFlashInit = function () { if (!this.flashInitialized) { try { if (this.audioHandleFlash && this.audioHandleFlash.initialize) { this.flashInitialized = true; this.audioHandleFlash.initialize(XAudioJSChannelsAllocated, XAudioJSVolume); } } catch (error) { this.flashInitialized = false; } } } //Set up the resampling: XAudioServer.prototype.resetCallbackAPIAudioBuffer = function (APISampleRate) { XAudioJSAudioBufferSize = XAudioJSResampleBufferEnd = XAudioJSResampleBufferStart = 0; this.initializeResampler(APISampleRate); XAudioJSResampledBuffer = this.getFloat32(XAudioJSResampleBufferSize); } XAudioServer.prototype.initializeResampler = function (sampleRate) { XAudioJSAudioContextSampleBuffer = this.getFloat32(XAudioJSMaxBufferSize); XAudioJSResampleControl = new Resampler(this.XAudioJSSampleRate, sampleRate, XAudioJSChannelsAllocated, XAudioJSAudioContextSampleBuffer); XAudioJSResampleBufferSize = XAudioJSResampleControl.outputBuffer.length; } XAudioServer.prototype.getFloat32 = function (size) { try { return new Float32Array(size); } catch (error) { return []; } } function XAudioJSFlashAudioEvent() { //The callback that flash calls... XAudioJSCallbackAPIEventNotificationCallbackCompatTimerClear(); XAudioJSCallbackAPIEventNotification(); XAudioJSResampleRefill(); var outputStr = XAudioJSFlashTransportEncoder(); XAudioJSCallbackAPIEventNotification2(); return outputStr; } function XAudioJSGenerateFlashSurroundString() { //Convert the arrays to one long string for speed. var XAudioJSTotalSamples = XAudioJSSamplesPerCallback << 1; if (XAudioJSBinaryString.length > XAudioJSTotalSamples) { XAudioJSBinaryString = []; } XAudioJSTotalSamples = 0; for (var index = 0; index < XAudioJSSamplesPerCallback && XAudioJSResampleBufferStart != XAudioJSResampleBufferEnd; ++index) { //Sanitize the buffer: XAudioJSBinaryString[XAudioJSTotalSamples++] = String.fromCharCode(((Math.min(Math.max(XAudioJSResampledBuffer[XAudioJSResampleBufferStart++] + 1, 0), 2) * 0x3FFF) | 0) + 0x3000); XAudioJSBinaryString[XAudioJSTotalSamples++] = String.fromCharCode(((Math.min(Math.max(XAudioJSResampledBuffer[XAudioJSResampleBufferStart++] + 1, 0), 2) * 0x3FFF) | 0) + 0x3000); XAudioJSResampleBufferStart += XAudioJSChannelsAllocated - 2; if (XAudioJSResampleBufferStart == XAudioJSResampleBufferSize) { XAudioJSResampleBufferStart = 0; } } return XAudioJSBinaryString.join(""); } function XAudioJSGenerateFlashStereoString() { //Convert the arrays to one long string for speed. var XAudioJSTotalSamples = XAudioJSSamplesPerCallback << 1; if (XAudioJSBinaryString.length > XAudioJSTotalSamples) { XAudioJSBinaryString = []; } for (var index = 0; index < XAudioJSTotalSamples && XAudioJSResampleBufferStart != XAudioJSResampleBufferEnd;) { //Sanitize the buffer: XAudioJSBinaryString[index++] = String.fromCharCode(((Math.min(Math.max(XAudioJSResampledBuffer[XAudioJSResampleBufferStart++] + 1, 0), 2) * 0x3FFF) | 0) + 0x3000); XAudioJSBinaryString[index++] = String.fromCharCode(((Math.min(Math.max(XAudioJSResampledBuffer[XAudioJSResampleBufferStart++] + 1, 0), 2) * 0x3FFF) | 0) + 0x3000); if (XAudioJSResampleBufferStart == XAudioJSResampleBufferSize) { XAudioJSResampleBufferStart = 0; } } return XAudioJSBinaryString.join(""); } function XAudioJSGenerateFlashMonoString() { //Convert the array to one long string for speed. if (XAudioJSBinaryString.length > XAudioJSSamplesPerCallback) { XAudioJSBinaryString = []; } for (var index = 0; index < XAudioJSSamplesPerCallback && XAudioJSResampleBufferStart != XAudioJSResampleBufferEnd;) { //Sanitize the buffer: XAudioJSBinaryString[index++] = String.fromCharCode(((Math.min(Math.max(XAudioJSResampledBuffer[XAudioJSResampleBufferStart++] + 1, 0), 2) * 0x3FFF) | 0) + 0x3000); if (XAudioJSResampleBufferStart == XAudioJSResampleBufferSize) { XAudioJSResampleBufferStart = 0; } } return XAudioJSBinaryString.join(""); } //Some Required Globals: var XAudioJSWebAudioContextHandle = null; var XAudioJSWebAudioAudioNode = null; var XAudioJSWebAudioWatchDogTimer = null; var XAudioJSCallbackAPIEventNotificationCallback = null; var XAudioJSCallbackAPIEventNotificationCallback2 = null; var XAudioJSCallbackAPIEventNotificationCallbackCompatTimer = setInterval(XAudioJSCallbackAPIEventNotificationDual, 16); var XAudioJSWebAudioWatchDogLast = false; var XAudioJSWebAudioLaunchedContext = false; var XAudioJSAudioContextSampleBuffer = []; var XAudioJSResampledBuffer = []; var XAudioJSMinBufferSize = 15000; var XAudioJSMaxBufferSize = 25000; var XAudioJSChannelsAllocated = 1; var XAudioJSVolume = 1; var XAudioJSResampleControl = null; var XAudioJSAudioBufferSize = 0; var XAudioJSResampleBufferStart = 0; var XAudioJSResampleBufferEnd = 0; var XAudioJSResampleBufferSize = 0; var XAudioJSMozAudioSampleRate = 44100; var XAudioJSSamplesPerCallback = 2048; //Has to be between 2048 and 4096 (If over, then samples are ignored, if under then silence is added). var XAudioJSFlashTransportEncoder = null; var XAudioJSBinaryString = []; function XAudioJSWebAudioEvent(event) { //Web Audio API callback... if (XAudioJSWebAudioWatchDogTimer) { XAudioJSWebAudioWatchDogLast = (new Date()).getTime(); } //Find all output channels: for (var bufferCount = 0, buffers = []; bufferCount < XAudioJSChannelsAllocated; ++bufferCount) { buffers[bufferCount] = event.outputBuffer.getChannelData(bufferCount); } XAudioJSCallbackAPIEventNotificationCallbackCompatTimerClear(); XAudioJSCallbackAPIEventNotification(); //Make sure we have resampled samples ready: XAudioJSResampleRefill(); //Copy samples from XAudioJS to the Web Audio API: for (var index = 0; index < XAudioJSSamplesPerCallback && XAudioJSResampleBufferStart != XAudioJSResampleBufferEnd; ++index) { for (bufferCount = 0; bufferCount < XAudioJSChannelsAllocated; ++bufferCount) { buffers[bufferCount][index] = XAudioJSResampledBuffer[XAudioJSResampleBufferStart++] * XAudioJSVolume; } if (XAudioJSResampleBufferStart == XAudioJSResampleBufferSize) { XAudioJSResampleBufferStart = 0; } } //Pad with silence if we're underrunning: while (index < XAudioJSSamplesPerCallback) { for (bufferCount = 0; bufferCount < XAudioJSChannelsAllocated; ++bufferCount) { buffers[bufferCount][index] = 0; } ++index; } XAudioJSCallbackAPIEventNotification2(); } function XAudioJSResampleRefill() { if (XAudioJSAudioBufferSize > 0) { //Resample a chunk of audio: var resampleLength = XAudioJSResampleControl.resampler(XAudioJSAudioBufferSize); var resampledResult = XAudioJSResampleControl.outputBuffer; for (var index2 = 0; index2 < resampleLength;) { XAudioJSResampledBuffer[XAudioJSResampleBufferEnd++] = resampledResult[index2++]; if (XAudioJSResampleBufferEnd == XAudioJSResampleBufferSize) { XAudioJSResampleBufferEnd = 0; } if (XAudioJSResampleBufferStart == XAudioJSResampleBufferEnd) { XAudioJSResampleBufferStart += XAudioJSChannelsAllocated; if (XAudioJSResampleBufferStart == XAudioJSResampleBufferSize) { XAudioJSResampleBufferStart = 0; } } } XAudioJSAudioBufferSize = 0; } } function XAudioJSCallbackAPIEventNotificationCallbackCompatTimerClear() { if (XAudioJSCallbackAPIEventNotificationCallbackCompatTimer) { clearInterval(XAudioJSCallbackAPIEventNotificationCallbackCompatTimer); } } function XAudioJSCallbackAPIEventNotification() { if (typeof XAudioJSCallbackAPIEventNotificationCallback == "function") { XAudioJSCallbackAPIEventNotificationCallback(); } } function XAudioJSCallbackAPIEventNotification2() { if (typeof XAudioJSCallbackAPIEventNotificationCallback2 == "function") { XAudioJSCallbackAPIEventNotificationCallback2(); } } function XAudioJSCallbackAPIEventNotificationDual() { XAudioJSCallbackAPIEventNotification(); XAudioJSCallbackAPIEventNotification2(); } function XAudioJSResampledSamplesLeft() { return ((XAudioJSResampleBufferStart <= XAudioJSResampleBufferEnd) ? 0 : XAudioJSResampleBufferSize) + XAudioJSResampleBufferEnd - XAudioJSResampleBufferStart; } function XAudioJSGetArraySlice(buffer, lengthOf) { //Typed array and normal array buffer section referencing: try { return buffer.subarray(0, lengthOf); } catch (error) { try { //Regular array pass: buffer.length = lengthOf; return buffer; } catch (error) { //Nightly Firefox 4 used to have the subarray function named as slice: return buffer.slice(0, lengthOf); } } }