AS3 appendBytes를 사용하여 AAC 스트리밍 오디오 용 NetStream 버퍼링을 조절하는 방법

Question

AAC 스트리밍 라디오 방송국에서 재생되는 오디오 샘플에 액세스하고이를 렌더러로 보내기 전에 신호 처리 기능을 수행하고 싶습니다.

URLStreamProgressEvent.PROGRESS 콜백을 사용하여 바이트 스트림에 액세스 할 수있었습니다. 해당 콜백 내에서 나는 원래 urlStream.readBytes(Bytes) 다음에 netStream.appendBytes(Bytes)을 호출했습니다. 몇 초 동안 오디오가 재생되고 netStatus가 NetStream.Buffer.Empty으로 중지됩니다.

내 ProgressEvent 처리기에 추적 코드를 넣고 netStream.bufferLength을 표시하고 처음에는 버퍼가 비게 될 때까지이 값이 더 커지는 것을 보았습니다. 버퍼를 조절하는 데 필요한 정보를 검색했지만 찾은 정보가 없습니다.

흥미롭게도, 내가 오히려 ProgressEvent 핸들러를 가능하게하기 위해 필요한 netStream.play(null),보다 netStream.play(url)을 실행할 때, 오디오는 잘 재생하지만 기본 오디오 샘플에 대한 가시성이 없습니다.

그럼 내 질문은 다음과 같습니다. 기본 오디오 샘플에 액세스하고 버퍼가 비어 있지 않게하려면 어떻게해야합니까?

package 
{ 
    import flash.display.Sprite; 

    import flash.net.NetConnection; 
    import flash.net.NetStream; 
    import flash.net.NetStreamAppendBytesAction; 
    import flash.net.NetStreamPlayOptions; 
    import flash.net.NetStreamInfo; 

    import flash.events.NetStatusEvent; 
    import flash.events.AsyncErrorEvent; 
    import flash.events.ProgressEvent; 
    import flash.events.Event; 

    import flash.net.URLRequest; 
    import flash.net.URLStream; 

    import flash.utils.*; 

    public class Main extends Sprite 
    { 
     private var connection:NetConnection = new NetConnection(); 
     private var netStream:NetStream = null; 
     private var urlStream:URLStream = null; 
     private var urlRequest:URLRequest = null; 

     private var inputSamples:ByteArray = new ByteArray(); 
     private var outputSamples:ByteArray = new ByteArray(); 

     private var hTimer:uint = 0; 
     private var nState:int = 1; 

     private var url:String="*** replace this text with your favorite streaming AAC radio feed ***"; 

     // Main Constructor 
     public function Main() : void 
     { 
      connectToStream(); 
     } 

     private function connectToStream() : void 
     { 
      connection.close(); 
      connection = new NetConnection(); 

      connection.addEventListener(NetStatusEvent.NET_STATUS, netStatusHandler); 
      connection.addEventListener(AsyncErrorEvent.ASYNC_ERROR, asyncErrorHandler); 
      connection.connect(null);   
     } 

     private function netStatusHandler(event:NetStatusEvent) : void 
     { 
      trace("NetStatusEvent = " + event.info.code); 
      switch (event.info.code) 
      { 
       case "NetConnection.Connect.Success": 
        requestAudio(); 
        break; 

       case "NetStream.Buffer.Empty": 

        //hTimer = setInterval(onTimerEvent, 1000); 

        break; 

      } // End switch 
     } 

     private function asyncErrorHandler(event:AsyncErrorEvent) : void 
     { 
      trace("Stream Error Handler - error = " + event); 
     } 

     public function onMetaData(info:Object) : void 
     { 
      trace("metadata: duration=" + info.duration + " framerate=" + info.framerate); 
     } 

     private function onTimerEvent() : void 
     { 

     } 

     private function requestAudio() : void 
     { 
      if (netStream !== null) 
      { 
       netStream.close(); 
      } 

      netStream = new NetStream(this.connection); 
      netStream.client = new Object(); 

      netStream.client.onMetaData = onMetaData; 

      netStream.addEventListener(NetStatusEvent.NET_STATUS, netStatusHandler); 
      netStream.addEventListener(AsyncErrorEvent.ASYNC_ERROR, asyncErrorHandler); 
      netStream.checkPolicyFile = false; 

      //netStream.play(url); 

      if (urlStream !== null) 
      { 
       urlStream.close(); 
      } 

      urlStream = new URLStream(); 
      urlStream.addEventListener(ProgressEvent.PROGRESS, progressHandler); 

      urlRequest = new URLRequest(url); 

      urlStream.load(urlRequest); 

      netStream.play(null); 

      netStream.appendBytesAction(NetStreamAppendBytesAction.RESET_BEGIN); 

     } 

     // Process audio samples from file 
     private function progressHandler(event:ProgressEvent) : void 
     { 
      var streamByte:int; 

      // Position to beginning of buffer 
      inputSamples.position = 0; 

      urlStream.readBytes(inputSamples); 

      // *** want to do some signal processing here *** 
      // For now just copy the input to the output 

      // Position to beginning of buffer 
      outputSamples.position = 0; 

      // This output indicates that the buffer is being drained 
      // until I get NetStream.Buffer.Empty and the audio stops playing 
      trace("Buffer Length = " + netStream.bufferLength); 

      while (inputSamples.bytesAvailable) 
      { 
       streamByte = inputSamples.readByte(); 

       outputSamples.writeByte(streamByte); 
      } 

      // Position to beginning of buffer 
      outputSamples.position = 0;    

      netStream.appendBytes(outputSamples);      
     } 
    } 
} 

Answer 1

이 시도 :

import flash.media.Video 

var stream = 'http://2583.live.streamtheworld.com/KFMXFMAAC' 

var http_stream:URLStream = null 

var video:Video = new Video() // the video is used only to ensure that stream is playing 
addChild(video) 

var nc:NetConnection = new NetConnection() 
    nc.connect(null) 
var ns:NetStream = new NetStream(nc) 
    ns.client = new Object() 
    ns.client.onMetaData = function(e){} 
    ns.play(null) 

video.attachNetStream(ns) 

http_stream = new URLStream(); 
http_stream.addEventListener(ProgressEvent.PROGRESS, on_Progress) 
http_stream.load(new URLRequest(stream)) 

function on_Progress(e:ProgressEvent):void { 

    var b:ByteArray = new ByteArray() 
    http_stream.readBytes(b, 0, http_stream.bytesAvailable) 
    ns.appendBytes(b) 

    trace(ns.bufferLength) 

}