Recipe 3.9. Detecting
the Device's Audio Capabilities
Problem
You want
to determine the audio capabilities of the device on which the
Flash Player is running.
Solution
Use the hasAudio and hasMP3 properties of the
flash.system.Capabilities
class.
Discussion
The flash.system.Capabilities.hasAudio
property returns TRue if the user's system has audio
capabilities and false otherwise. This is extremely
important for playing movies on multiple devices. If a device has
no audio support, you want to avoid forcing users to download
something they cannot hear (especially because audio can be quite
large).
// Load a .swf containing sound only if the Player can play audio
if (flash.system.Capabilities.hasAudio) {
content = "sound.swf";
} else {
content = "silent.swf";
}
// code to load the .swf referenced in content
Just because a system has audio capabilities,
however, does not necessarily mean that it can play back MP3
sounds. Therefore, if publishing MP3 content, you should test for
MP3 capabilities using the
flash.system.Capabilities.hasMP3 property. MP3 sounds are preferable, if
supported, because they offer better sound quality to file size
ratios than ADCP sounds.
// If the Player can play MP3s, load an MP3 using a Sound object.
// Otherwise, load a .swf containing ADCP sound into a nested
// sprite.
if (flash.system.Capabilities.hasMP3) {
var url:URLRequest = new URLRequest("sound.mp3");
sound = new Sound(url);
sound.play( );
} else {
// code to load an external .swf containing a ADCP sound
}
It is important to understand that the
hasAudio and hasMP3 property settings are based
on the capabilities of the Player and not of the system on which
the Player is running. The desktop system players (for Windows, Mac
OS, and Linux) always return TRue for both properties
regardless of whether or not the system actually has the hardware
(i.e., soundcard and speakers) to play back sounds. However,
players for other devices may return false if the device
does not support the audio or MP3 features.
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