Slice ArrayBuffer with Safari and play it - safari

Question

I need to load a mp3, slice and play it using web audio , on firefox a slice mp3 any where and decode work fine, but on safari an error with null value occurs. Exist a trick or a way do slice the ArrayBuffer on Safari?
player.loadMp3 = function(url, callback) {
var request = new XMLHttpRequest();
request.open('GET', url, true);
request.responseType = 'arraybuffer';
request.onload = function() {
var mp3slice = request.response.slice(1000,100000);
player.context.decodeAudioData(mp3slice); // context is webkitAudioContext on safari
callback();
};
request.send();
};
I need to create a mp3 player with some especial features:
Time shift the music (like http://codepen.io/eranshapira/pen/mnuoB)
Remove gap between musics ( I got this slicing ArrayBuffers and join then with a Blob but only in safary/IPAD don't work).
Cross platform (IPAD and android. I'm using apache cordova for that).
Solution
player.loadMp3 = function(url, callback) {
console.log("loading " + url);
var request = new XMLHttpRequest();
request.open('GET', url, true);
request.responseType = 'arraybuffer';
request.onload = function() {
console.log("loaded");
console.log("decoding...");
player.context.decodeAudioData(request.response, function(buffer) {
console.log("decoded");
player.buffer = player.joinAudioBuffers(player.buffer,buffer,2000000);
player.duration += player.buffer.duration;
player.time = minsSecs(player.buffer.duration);
console.log("concatenated");
callback();
});
}, function() {
alert("decode failure");
};
request.send();
};

Answer 1

The code you've shown shouldn't work on any browser. For one thing you need to provide a callback function to decodeAudioData. You also need to slice the decoded data after decoding it, not the raw mp3-encoded data before decoding it. Some browsers might be able to decode a slice of the mp3 file, but it's not expected. Something like this:
player.loadMp3 = function(url, callback) {
var request = new XMLHttpRequest();
request.open('GET', url, true);
request.responseType = 'arraybuffer';
request.onload = function() {
var mp3slice = request.response.slice(1000,100000);
player.context.decodeAudioData(mp3slice, function(decoded) {
var pcmSlice = decoded.slice(1000, 100000);
callback(pcmSlice);
});
};
request.send();
};
I haven't tested this code.