Tonfall DemoLatency.as

by janogarcia 28 Apr 2011

Tags

sound
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/**
 * Copyright janogarcia ( http://wonderfl.net/user/janogarcia )
 * GNU General Public License, v3 ( http://www.gnu.org/licenses/quick-guide-gplv3.html )
 * Downloaded from: http://wonderfl.net/c/pY3o
 */

package demo
{
    import flash.display.Sprite;
    import flash.display.StageAlign;
    import flash.display.StageScaleMode;
    import flash.events.Event;
    import flash.events.SampleDataEvent;
    import flash.media.Sound;
    import flash.media.SoundChannel;
    import flash.system.Capabilities;
    import flash.text.TextField;
    import flash.text.TextFieldAutoSize;
    import flash.text.TextFormat;
    import flash.utils.ByteArray;

    /**
     * Quick LatencyCheck
     * 
     * @author Andre Michelle
     */
    [SWF(backgroundColor="#DDDDDD", frameRate="31", width="512", height="96")]
    public final class DemoLatency extends Sprite
    {
        private static const TESTS: Vector.<int> = Vector.<int>( [ 2048, 3072, 4096, 8192 ] );
        
        private const buffer: ByteArray = new ByteArray();
        
        private const sounds: Vector.<Sound> = new Vector.<Sound>();
        private const channels: Vector.<SoundChannel> = new Vector.<SoundChannel>();
        
        private const textField: TextField = new TextField();
        private const outputs: Vector.<String> = new Vector.<String>();
        
        private var _buildIndex: int = 0;
        
        public function DemoLatency()
        {
            textField.autoSize = TextFieldAutoSize.LEFT;
            textField.defaultTextFormat = new TextFormat( 'Verdana', 10, 0x0, false );
            textField.text = '';
            addChild( textField );
            
            buffer.length = TESTS[ int( TESTS.length - 1 ) ] << 3; // MAX SAMPLES * sizeof float (times two: stereo)
            
            stage.align = StageAlign.TOP_LEFT;
            stage.scaleMode = StageScaleMode.NO_SCALE;
            stage.addEventListener( Event.ENTER_FRAME, enterFrame );
        }

        private function enterFrame( event: Event ): void
        {
            if( _buildIndex < TESTS.length )
            {
                sounds[_buildIndex] = new Sound();
                sounds[_buildIndex].addEventListener( SampleDataEvent.SAMPLE_DATA, sampleData );
                channels[_buildIndex] = sounds[_buildIndex].play();
                
                ++_buildIndex;
            }
            
            textField.text = '';
            textField.appendText( 'System\t' + Capabilities.os + '\n' );
            textField.appendText( 'Player\t' + Capabilities.version + ' ' + Capabilities.playerType + '\n' );
            textField.appendText( '--------------------------------------------------------------------\n' );
            
            var i: int = 0;
            var n: int = outputs.length;
            
            for( ; i < n ; ++i )
            {
                textField.appendText( outputs[i] + '\n' );
            }
        }

        private function sampleData( event: SampleDataEvent ): void
        {
            var index: int = sounds.indexOf( event.target );
            
            if( -1 == index )
                throw new Error();

            buffer.position = 0;
            
            event.data.writeBytes( buffer, 0, TESTS[index] << 3 );
                
            if( channels.length > index && channels[index] != null )
            {
                // Compute difference from writing and audible audio data
                const latency: Number = event.position / 44.1 - channels[index].position;

                outputs[index] = 'Providing ' + TESTS[index] + ' samples results in ' + latency.toFixed(3) + 'ms latency';
            }
        }
    }
}