Android VideoCapture : Use NV21 instead of YUV12 and clean up.

talk/app/webrtc/java/android/org/webrtc/CameraEnumerationAndroid.java

Index: talk/app/webrtc/java/android/org/webrtc/CameraEnumerationAndroid.java
diff --git a/talk/app/webrtc/java/android/org/webrtc/CameraEnumerationAndroid.java b/talk/app/webrtc/java/android/org/webrtc/CameraEnumerationAndroid.java
index 32341a342122acfaef980e0a67bcf511af9bbb3d..14c5ff171282ec5b5f3b05ef9c4ccb567d9141be 100644
--- a/talk/app/webrtc/java/android/org/webrtc/CameraEnumerationAndroid.java
+++ b/talk/app/webrtc/java/android/org/webrtc/CameraEnumerationAndroid.java
@@ -71,7 +71,7 @@ public class CameraEnumerationAndroid {
     // other image formats then this needs to be updated and
     // VideoCapturerAndroid.getSupportedFormats need to return CaptureFormats of
     // all imageFormats.
-    public final int imageFormat = ImageFormat.YV12;
+    public final int imageFormat = ImageFormat.NV21;
 
     public CaptureFormat(int width, int height, int minFramerate,
         int maxFramerate) {
@@ -87,20 +87,18 @@ public class CameraEnumerationAndroid {
     }
 
     // Calculates the frame size of the specified image format. Currently only
-    // supporting ImageFormat.YV12. The YV12's stride is the closest rounded up
+    // supporting ImageFormat.NV21. The stride is the closest rounded up
     // multiple of 16 of the width and width and height are always even.

[magjed_webrtc, 2015/12/17 08:02:42]

Why did you remove the android link? I'm not sure the stride is a multiple of 16
for NV21. The documentation says: "For YV12, the image buffer that is received
is not necessarily tightly packed, as there may be padding at the end of each
row of pixel data, as described in YV12". Sounds like this is not the case for
NV21? Please look it up and provide a reference.

[perkj_webrtc, 2015/12/17 12:42:44]

Done.

-    // Android guarantees this:
-    // http://developer.android.com/reference/android/hardware/Camera.Parameters.html#setPreviewFormat%28int%29
     public static int frameSize(int width, int height, int imageFormat) {
-      if (imageFormat != ImageFormat.YV12) {
+      if (imageFormat != ImageFormat.NV21) {
         throw new UnsupportedOperationException("Don't know how to calculate "
-            + "the frame size of non-YV12 image formats.");
+            + "the frame size of non-NV21 image formats.");
       }
-      int yStride = roundUp(width, 16);
-      int uvStride = roundUp(yStride / 2, 16);
-      int ySize = yStride * height;
-      int uvSize = uvStride * height / 2;
-      return ySize + uvSize * 2;
+      final int stride = roundUp(width, 16);
+      final int ySize = stride * height;
+      final int uvHeight = (height + 1) / 2;
+      final int uvSize = stride * uvHeight;
+      return ySize + uvSize;
     }
 
     // Rounds up |x| to the closest value that is a multiple of |alignment|.