title: AS3 JPGEncoder: I don't want black background
body: <p>I have the following code to create a jpg file from a movieclip:</p>
  
  <pre><code>var translateMatrix:Matrix = new Matrix();      
  translateMatrix.scale(1, 1); // (0.746, 0.746);
  translateMatrix.translate(100, 150);
  
  var myBitmap:BitmapData = new BitmapData(500, 500, false, 0x00000000);
  myBitmap.draw(muneca, translateMatrix, null, "normal", null, true);
  var encoder:JPGEncoder = new JPGEncoder(80);
  var byteArray:ByteArray = encoder.encode(myBitmap);
  
  var file:FileReference = new FileReference();
  file.save(byteArray, "photo.jpg");
  </code></pre>
  
  <p>However, the transparent parts of the movieclip (background) are black in the final jpg. How can I transform those black parts into white?</p>
  
  <p>Thank you very much</p>