Recipe 15.7. Reading the ID3 Tag of a Sound File

Problem

You want to access information about the MP3 file you are playing, such as the name of the song, artist, album, genre, etc.

Solution

Read the id3 property of the Sound object.

Discussion

MP3 audio files are able to contain an abundance of metadata about the sound. This is most often used in music files to record the name of the song, the artist, album, genre, year of release, composer, etc. How much information is actually included in these tags depends on who encoded or tagged the file. In most cases though, you'll at least be able to get at the songname and artist tag.

This data is available to you in ActionScript through the id3 property of a Sound object.

This property is an instance of the flash.media.ID3Info class, which contains the following properties:

album
artist
comment
genre
songName
TRack
year

So, to read the song's name, you would access it as follows:

_sound.id3.songName

There is just one catch to all of this, though: you can't access these id3 tags until they have actually downloaded into your .swf. If you try to read a tag immediately after you create your Sound object or call play( ), it won't be defined. Factually, the request for the sound file has probably not even reached the server at that point, so of course there will be no tag data available.

So, how do you know when this id3 data is available? Fortunately, the Sound object has an ID3 event that you can listen for. When this event fires, it is safe to read the id3 tags. The Sound class extends the EventDispatcher class, so you can use add- EventDispatcher to listen for this event, which is defined as flash.events.Event.ID3, and assign a handler method to it; this is the method to use for reading the id3 tags.

The following example creates a text field and lists all available id3 tags:

package {     import flash.display.Sprite;     import flash.media.Sound;     import flash.net.URLRequest;     import flash.events.Event;     import flash.text.TextField;          public class ID3Reader extends Sprite {         private var _sound:Sound;                  public function ID3Reader (  ) {             _sound = new Sound(new URLRequest("song.mp3"));             _sound.addEventListener(Event.ID3, onID3);             _sound.play(  );         }                  public function onID3(event:Event):void {             // Create a text field and display it             var id3Display:TextField = new TextField(  );             addChild(id3Display);             id3Display.x = 10;             id3Display.y = 20;             id3Display.width = 200;             id3Display.height = 200;             id3Display.background = true;             id3Display.multiline = true;             id3Display.wordWrap = true;             // Add some info about the song to the text field             id3Display.text += _sound.id3.songName + "\n";             id3Display.text += _sound.id3.artist + "\n";             id3Display.text += _sound.id3.album + "\n";             id3Display.text += _sound.id3.year + "\n";            }         }     } }

Problem

Solution

Discussion

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