Estou tentando obter este exemplo de API de áudio da web para ser executado no iOS (7.x, 8.x) Safari / Chrome: link
Mas infelizmente não vai. Alguém pode explicar por quê?
// create the audio context (chrome only for now)
// create the audio context (chrome only for now)
if (! window.AudioContext) {
if (! window.webkitAudioContext) {
alert('no audiocontext found');
}
window.AudioContext = window.webkitAudioContext;
}
var context = new AudioContext();
var audioBuffer;
var sourceNode;
var analyser;
var javascriptNode;
// get the context from the canvas to draw on
var ctx = $("#canvas").get()[0].getContext("2d");
// create a gradient for the fill. Note the strange
// offset, since the gradient is calculated based on
// the canvas, not the specific element we draw
var gradient = ctx.createLinearGradient(0,0,0,300);
gradient.addColorStop(1,'#000000');
gradient.addColorStop(0.75,'#ff0000');
gradient.addColorStop(0.25,'#ffff00');
gradient.addColorStop(0,'#ffffff');
// load the sound
setupAudioNodes();
loadSound("wagner-short.ogg");
function setupAudioNodes() {
// setup a javascript node
javascriptNode = context.createScriptProcessor(2048, 1, 1);
// connect to destination, else it isn't called
javascriptNode.connect(context.destination);
// setup a analyzer
analyser = context.createAnalyser();
analyser.smoothingTimeConstant = 0.3;
analyser.fftSize = 512;
// create a buffer source node
sourceNode = context.createBufferSource();
sourceNode.connect(analyser);
analyser.connect(javascriptNode);
sourceNode.connect(context.destination);
}
// load the specified sound
function loadSound(url) {
var request = new XMLHttpRequest();
request.open('GET', url, true);
request.responseType = 'arraybuffer';
// When loaded decode the data
request.onload = function() {
// decode the data
context.decodeAudioData(request.response, function(buffer) {
// when the audio is decoded play the sound
playSound(buffer);
}, onError);
}
request.send();
}
function playSound(buffer) {
sourceNode.buffer = buffer;
sourceNode.start(0);
}
// log if an error occurs
function onError(e) {
console.log(e);
}
// when the javascript node is called
// we use information from the analyzer node
// to draw the volume
javascriptNode.onaudioprocess = function() {
// get the average for the first channel
var array = new Uint8Array(analyser.frequencyBinCount);
analyser.getByteFrequencyData(array);
// clear the current state
ctx.clearRect(0, 0, 1000, 325);
// set the fill style
ctx.fillStyle=gradient;
drawSpectrum(array);
}
function drawSpectrum(array) {
for ( var i = 0; i < (array.length); i++ ){
var value = array[i];
ctx.fillRect(i*5,325-value,3,325);
// console.log([i,value])
}
};