How do I know when audio is ready to be played in HTML5?

#1

Hi,
this can be considered a twin-topic of discussion

sound-not-playing-on-html5-target-ios

We all know that in iOS sound must be unmuted before we can hear it, but before this there is another problem: when I load a game I have to download sounds, and in HTML5 sounds are not loaded completely before game starts, they are “streamed”, I can just say “start downloading sound files”, and I will hear them only when they are ready.
So, how do I know when a sound file is ready to be played? More in detail, how do I know when a music can be played? When coding in AS3 I use Greensock libraries that tell me when enough data has been downloaded to allow me to play a music… how can I do it in Openfl?
Maybe I have to periodically try to play it, or check if it is not null?

#2

You can use the Sound’s “complete” event. It works perfectly on HTML5 on desktop browsers. Would this work on iOS browser as well?

// assuming _sound is an openfl.media.Sound instance
this._sound.addEventListener(Event.COMPLETE, completeHandler);
#3

I already use this event for loading sounds, and in HTML5 target (on iOS and Android) loading is instantaneous, that means it just starts the download: if i try to play sounds immediately after the COMPLETE event I can’t hear them.

#4

If you are using openfl.media.Sound, you can just treat it like AS3.

var snd = new Sound();
snd.addEventListener( Event.COMPLETE, onLoaded );
snd.load( new URLRequest( "some/url.mp3" );

Then for playback complete:

var sndChannel = snd.play();
sndChannel.addEventListener( Event.SOUND_COMPLETE, onSoundFinished );

This works on iOS/Safari (and the rest of the browsers on mobile/PC), so long as you are using a supported sound type. If you try to load an OGG on iOS for example (even if it’s just a fallback you know isn’t supported) sound will not play at all for some reason. It seems maybe Safari doesn’t follow through when it encounters a file type it doesn’t know what to do with.

#5

I need to use loadSound of Assets.hx because I want to use its caching feature. Anyway I am pretty sure that sound download in JS works the same using snd.load(“urlRequest”) too: I think it simply launches a “GET url” like loadSound and returns a COMPLETE event immediately, but I should test this.

So… do you think I can detect when download is complete?

#6

I know with Assets, there is a second param for an onComplete function for every load method. It is commented as deprecated, but as far as I know still works. @singmajesty would know if events or other methods are advised here to catch load completion through Assets.

#7

I am trying to see if it works.
Alternatively is it possible to know if a sound is being played? I could try to play music repeatedly until it effectively starts.

#8

There are a few more sound properties that could help you out here.

Loading related:

  • isBuffering
  • bytesLoaded / bytesTotal

Playing related:

  • sound.play() returns a SoundChannel. I believe null is returned if it failed to play.
  • I don’t think there’s any simple way to find if a sound is currently playing. For that, you may just need to write a wrapper class where you can track a bool yourself.
#9

isBuffering returns false
bytesLoaded returns 0
playing the file the resulting soundChannel is not null

Even if the file has not been downloaded yet I am not able to understand when it effectively is complete or is playing, I have no clue on how to play this sound file at the right time.

If I play it every 1sec I have to wait about 10 seconds for download and then it starts playing, restarting every second.
It is like I am blind and can’t see what’s doing/downloading.