Html5 Audio Tag on Safari Has a Delay

HTML5 Audio tag on Safari has a delay

I just answered another iOS/<audio> question a few minutes ago. Seems to apply here as well:

Preloading <audio> and <video> on iOS devices is disabled to save bandwidth.

In Safari on iOS (for all devices, including iPad), where the user may
be on a cellular network and be charged per data unit, preload and
autoplay are disabled. No data is loaded until the user initiates it.

Source: Safari Developer Library

Audio delay on Safari Desktop

I was not able to remove the delay completely, but I made it much better by setting preload to ="metadata". For some reason it makes files load much quicker for playback.

Chrome actually is smart about this. When the preload is set to auto, it caches around 1mb of each audio file upon page load, so it can play it quicker when you press "Play" button.

I also started listening to onwaiting event of the audio element, so I can show the preloader to make experience a little bit better.

Since Safari fires oncanplay and onplaying much sooner when the file is actually ready to play, I don't just hide preloader on this events, but after a 1.5 second timeout to smooth it out.

That's good enough for me, since the lag decreased from 30 seconds (with 10 audio elements on page) to just 1.5 seconds.

Safari behaving very weirdy with HTML5 audio tag

You might have better luck and more control if you don't use the <audio> tag. You'll need to make your own play button and slider if you want those controls. And use Web Audio API by itself to download and decode and play a track.

var url = "whatever.mp3";
var source = audioCtx.createBufferSource();
var buffers = {};

var request = new XMLHttpRequest();
request.open('GET', url, true);
request.responseType = 'arraybuffer';

request.onload = function () {
    audioCtx.decodeAudioData(request.response, function (buffer) {
        source.buffer = buffer;
        source.connect(audioCtx.destination);
        source.start(audioCtx.currentTime);

        // save this for later, so you can replay it without downloading
        buffers[url] = buffer; 

    }, function () {
        console.warn("error loading sound url: " + url);
    });
}
request.send();

Audio delay on HTML5 mobile web app

The audio delay may be because of buffering issues in iOS that are there due to cellular data charges. The user has to explicitly trigger the event in order for the content to start being downloaded.

In Safari on iOS (for all devices, including iPad), where the user may be on a cellular network and be charged per data unit, preload and autoplay are disabled. No data is loaded until the user initiates it. This means the JavaScript play() and load() methods are also inactive until the user initiates playback, unless the play() or load() method is triggered by user action. In other words, a user-initiated Play button works, but an onLoad="play()" event does not.

-https://developer.apple.com/library/safari/documentation/AudioVideo/Conceptual/Using_HTML5_Audio_Video/Device-SpecificConsiderations/Device-SpecificConsiderations.html#//apple_ref/doc/uid/TP40009523-CH5-SW1

=== EDIT ===

One potential improvement is to use lower bitrate/ higher compressed audio for mobile products. The quality will, however, be significantly reduced. Use only if it is acceptable in your application.

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