Andre Michelle a un grand article on Pitch contrôle avec actionscript 3.0
Pour référence, voici le code exemple d'André:
package components
{
import flash.events.Event;
import flash.events.SampleDataEvent;
import flash.media.Sound;
import flash.net.URLRequest;
import flash.utils.ByteArray;
/**
* @author Andre Michelle ([email protected])
*/
public class MP3Pitch
{
private const BLOCK_SIZE: int = 3072;
private var _mp3: Sound;
private var _sound: Sound;
private var _target: ByteArray;
private var _position: Number;
private var _rate: Number;
public function MP3Pitch(url: String)
{
_target = new ByteArray();
_mp3 = new Sound();
_mp3.addEventListener(Event.COMPLETE, complete);
_mp3.load(new URLRequest(url));
_position = 0.0;
_rate = 1.0;
_sound = new Sound();
_sound.addEventListener(SampleDataEvent.SAMPLE_DATA, sampleData);
}
public function get rate(): Number
{
return _rate;
}
public function set rate(value: Number): void
{
if(value < 0.0)
value = 0;
_rate = value;
}
private function complete(event: Event): void
{
_sound.play();
}
private function sampleData(event: SampleDataEvent): void
{
//-- REUSE INSTEAD OF RECREATION
_target.position = 0;
//-- SHORTCUT
var data: ByteArray = event.data;
var scaledBlockSize: Number = BLOCK_SIZE * _rate;
var positionInt: int = _position;
var alpha: Number = _position - positionInt;
var positionTargetNum: Number = alpha;
var positionTargetInt: int = -1;
//-- COMPUTE NUMBER OF SAMPLES NEED TO PROCESS BLOCK (+2 FOR INTERPOLATION)
var need: int = Math.ceil(scaledBlockSize) + 2;
//-- EXTRACT SAMPLES
var read: int = _mp3.extract(_target, need, positionInt);
var n: int = read == need ? BLOCK_SIZE : read/_rate;
var l0: Number;
var r0: Number;
var l1: Number;
var r1: Number;
for(var i: int = 0 ; i < n ; ++i)
{
//-- AVOID READING EQUAL SAMPLES, IF RATE < 1.0
if(int(positionTargetNum) != positionTargetInt)
{
positionTargetInt = positionTargetNum;
//-- SET TARGET READ POSITION
_target.position = positionTargetInt << 3;
//-- READ TWO STEREO SAMPLES FOR LINEAR INTERPOLATION
l0 = _target.readFloat();
r0 = _target.readFloat();
l1 = _target.readFloat();
r1 = _target.readFloat();
}
//-- WRITE INTERPOLATED AMPLITUDES INTO STREAM
data.writeFloat(l0 + alpha * (l1 - l0));
data.writeFloat(r0 + alpha * (r1 - r0));
//-- INCREASE TARGET POSITION
positionTargetNum += _rate;
//-- INCREASE FRACTION AND CLAMP BETWEEN 0 AND 1
alpha += _rate;
while(alpha >= 1.0) --alpha;
}
//-- FILL REST OF STREAM WITH ZEROs
if(i < BLOCK_SIZE)
{
while(i < BLOCK_SIZE)
{
data.writeFloat(0.0);
data.writeFloat(0.0);
++i;
}
}
//-- INCREASE SOUND POSITION
_position += scaledBlockSize;
}
}
}
utilisation de base serait quelque chose comme:
//create an MP3Pitch instance and load a sound
var mp3:MP3Pitch = new MP3Pitch("/path/to/your/file.mp3");
//change the pitch via rate setter
mp3.rate += 0.5
incroyable! merci de m'avoir indiqué cela! – TheDarkIn1978
content que ça aide. Initialement, Lee Brimelow (http://theflashblog.com/?p=1129) avait un article à ce sujet, mais Sound est le domaine d'expertise d'André Michelle. –
-1 parce que les articles sont des liens brisés. Ainsi, nous voyons l'importance d'au moins mettre un peu de réponse comme votre «réponse», pas seulement des liens. –