@walkietokyo，非常感谢您为我指明了正确的方向。我成功地做了我想做的事。这里的关键字是loadCompressedDataFromByteArray 函数。
经过数十次反复试验，我发现loadCompressedDataFromByteArray 以不同的方式工作。
它附加任何它转换到声音对象的末尾数据。
另一个问题：在调用play 函数后，声音对象不会继续播放loadCompressedDataFromByteArray 附加的部分。
所以我实现了一种双缓冲。我可以互换使用 2 个声音对象。
下面列出了我的最终（测试）版本。使用我使用的加密（混淆）方法（一个简单的 XOR），我测试的任何下载管理器、抓取器或嗅探器都无法播放 Mp3。
Flash（客户端）端：
import flash.events.DataEvent;
import flash.events.Event;
import flash.events.EventDispatcher;
import flash.events.OutputProgressEvent;
import flash.events.ProgressEvent;
import flash.net.URLRequest;
import flash.net.URLStream;
import flash.utils.ByteArray;
import flashx.textLayout.formats.Float;
var buffer:ByteArray;
var stream:URLStream;
var bufferReadPosition:uint = 0;
var bufferWritePosition:uint = 0;
var url:String = "http://www.blablabla.com/MusicServer.aspx?" + (new Date());
buffer = new ByteArray();
stream = new URLStream();
stream.addEventListener(ProgressEvent.PROGRESS, onProgress);
stream.load(new URLRequest(url));
var s1:Sound = new Sound();
var s2:Sound = new Sound();
var channel1:SoundChannel;
var channel2:SoundChannel;
var pausePosition:int = 0;
var aSoundIsPlaying:Boolean = false;
var lastLoadedS1:Boolean = false;
var lastS1Length:int = 0;
var lastS2Length:int = 0;
function onProgress(e:ProgressEvent):void {
var tmpData:ByteArray = new ByteArray();
stream.readBytes(tmpData, 0, stream.bytesAvailable);
var decryptedData:ByteArray = decryptData(tmpData); // Decrypt loaded data
buffer.position = bufferWritePosition;
buffer.writeBytes(decryptedData, 0, decryptedData.length); // Add decrypted data to buffer
bufferWritePosition += decryptedData.length;
if(lastLoadedS1)
{
buffer.position = lastS2Length;
s2.loadCompressedDataFromByteArray(buffer, buffer.length - lastS2Length);
lastS2Length = buffer.length;
}
else
{
buffer.position = lastS1Length;
s1.loadCompressedDataFromByteArray(buffer, buffer.length - lastS1Length);
lastS1Length = buffer.length;
}
if(!aSoundIsPlaying)
{
DecidePlay();
}
}
function channel1Completed(e:Event):void
{
DecidePlay();
}
function channel2Completed(e:Event):void
{
DecidePlay();
}
function DecidePlay():void
{
aSoundIsPlaying = false;
if(lastLoadedS1)
{
channel1.stop();
if(s2.length - s1.length > 10000)
{
//At least a 10 second buffer
channel2 = s2.play(s1.length);
channel2.addEventListener(Event.SOUND_COMPLETE, channel2Completed);
lastLoadedS1 = false;
aSoundIsPlaying = true;
}
}
else
{
if(channel2 != null)
{
channel2.stop();
}
if(s1.length - s2.length > 10000)
{
//At least a 10 second buffer
channel1 = s1.play(s2.length);
channel1.addEventListener(Event.SOUND_COMPLETE, channel1Completed);
lastLoadedS1 = true;
aSoundIsPlaying = true;
}
}
}
function decryptData(data:ByteArray):ByteArray {
for(var i:int = 0;i<data.length;i++)
{
//Here put in your bitwise decryption code
}
return data;
}
ASP.NET 服务器端（MusicServer.aspx）：
protected void Page_Load(object sender, EventArgs e)
{
CopyStream(Mp3ToStream(Server.MapPath("blabla.mp3")), Response.OutputStream);
this.Response.AddHeader("Content-Disposition", "blabla.mp3");
this.Response.ContentType = "audio/mpeg";
this.Response.End();
}
public static void CopyStream(Stream input, Stream output)
{
byte[] buffer = new byte[32768];
int read;
while ((read = input.Read(buffer, 0, buffer.Length)) > 0)
{
for (int i = 0; i < read; i++)
{
//Here put in your bitwise encryption code
}
output.Write(buffer, 0, read);
}
}
public Stream Mp3ToStream(string filePath)
{
using (FileStream fileStream = File.OpenRead(filePath))
{
MemoryStream memStream = new MemoryStream();
memStream.SetLength(fileStream.Length);
fileStream.Read(memStream.GetBuffer(), 0, (int)fileStream.Length);
return memStream;
}
}