Use PNG frame format by default.

Non Oracle JDKs do not support writing JPG frames that have alpha channel.

See https://bugs.openjdk.java.net/browse/JDK-8211748 for details.

Author: xSAVIKx

src/main/java/com/github/xsavikx/androidscreencast/api/injector/ScreenCaptureRunnable.java

@@ -129,10 +129,9 @@ public void setListener(final ScreenCaptureListener listener) {
         this.listener = listener;
     }
 
-
     public void startRecording(final File file) {
         try {
-            qos = new QuickTimeOutputStream(file, QuickTimeOutputStream.VideoFormat.JPG);
+            qos = new QuickTimeOutputStream(file, QuickTimeOutputStream.VideoFormat.PNG);
             qos.setVideoCompressionQuality(MOV_COMPRESSION_RATE);
             qos.setTimeScale(MOV_FPS);
         } catch (final IOException e) {