Comments on: Calculating duration on mp3s in AS3

By: rob

rob — Sun, 17 Jan 2010 20:03:50 +0000

Hi! The code works, but not when I load a MP3. If a trace the sound.length it's display an increasing value of the length until the sound finished loading.

I want to start playing the sound while its's loading and show the position of the sound in a mc.

Is it possible?

By: marpies

marpies — Tue, 16 Jun 2009 13:33:41 +0000

Amazing, working so nicely!

Thanks so much Steven!

By: Isuru

Isuru — Fri, 27 Mar 2009 06:33:39 +0000

its work on localy but not in server

By: Doug

Doug — Thu, 26 Mar 2009 04:28:17 +0000

thanks steven & dudan, perfect!

By: dudan

dudan — Fri, 27 Feb 2009 10:00:30 +0000

This code works nicely, cheers!

I found it a bit fiddly trying to work out the track time correctly, so here it is for anybody else:

var Milliseconds:Number = (music.bytesTotal / (music.bytesLoaded / music.length));

var Minutes:uint = Math.floor(Milliseconds/60000);
var Seconds:uint = (Milliseconds%60000);
var SecondsTens:uint = Math.floor(Seconds/10000);

Seconds = Math.ceil(Seconds%10000)
Seconds /= 1000;

trace(Minutes + ":" + SecondsTens + "" + Seconds);

dudan

By: Steven Sacks

Steven Sacks — Wed, 10 Dec 2008 05:06:44 +0000

Unfortunately, as I found out from the Flash player team at MAX, iTunes uses its own version of ID3v2 that Flash cannot detect so it never fires an ID3 event nor can it be read via the ID3 class.

So, for reliable ID3 access, you should use metaphile.

However, not all mp3s have useful ID3 data, so when you're loading mp3s that are not in your control, this estimation is as good as it gets, and it's pretty damn good. I've tested it on a bunch of mp3s from Seeqpod and it works great.

By: Patrick Matte

Patrick Matte — Wed, 10 Dec 2008 04:47:39 +0000

There are some id3 editors that will automatically add a length property to the id3 tag. Then you can get that value from the id3 event dispatched by the sound object.

By: Steven Sacks

Steven Sacks — Wed, 03 Dec 2008 06:13:32 +0000

@Matt – It's accurate to within a few seconds before 5 seconds, and by 5-7 seconds it's within a second. After 10 seconds, you're within a few hundred milliseconds. Suffice to say, it's accurate enough to be fractions of pixels on scrub bars from the start. You won't be able to see it. If you have a duration field, it might jump a little at the beginning, but it's not too noticable and it's over quickly enough.

@Phillip – My way really works, but as you mentioned, it only works with CBR, and might only work with 16/44 but non 16/44 have issues anyway. VBRs have never really worked with Flash anyway. They either work just fine, or they end up triggering SoundComplete before they're actually complete, or just stopping during playback altogether. FP10 allows you bring in the mp3 as a byte stream, so theoretically (I haven't tested it), you can finally play VBRs in Flash with some reliability.

By: Phillip Kerman

Phillip Kerman — Wed, 03 Dec 2008 05:14:45 +0000

My brain is hurting thinking about whether your way really works. Seems like if you know the bitrate of the mp3 and it's CBR (not VBR) then you could just divide the bytes total by the bitrate to get a good duration.

I'll probably wake up in the middle of the night have an epiphany… what the heck is Flash's duration reporting anyway? I wonder if the correct info is in the file's header.

By: Matt Przybylski

Matt Przybylski — Tue, 02 Dec 2008 21:29:16 +0000

Steven,
Without having tried this myself, how accurate is it when compared to what you get when the sound is actually loaded?