The max video frame size was too small (640x480). increase it to handle HD (1280x720).
Fix failures to generate thumbnails for HD contents.
diff --git a/android/metadatadriver.h b/android/metadatadriver.h
index 392b9d5..e714024 100644
--- a/android/metadatadriver.h
+++ b/android/metadatadriver.h
@@ -124,7 +124,7 @@
     // We support get metadata, or get frame, or get both, or get neigther.
     static const uint32 GET_METADATA_ONLY    = (0x01 << 0);
     static const uint32 GET_FRAME_ONLY       = (0x01 << 1);
-    static const uint32 MAX_VIDEO_FRAME_SIZE = 640 * 480 * 4;  // Big enough?
+    static const uint32 MAX_VIDEO_FRAME_SIZE = 1280 * 720 * 4;  // Big enough?
     static const uint32 MAX_METADATA_STRING_LENGTH = 128;
     static const uint32 MAX_STRING_LENGTH = 512;
     static const uint32 NUM_METADATA_KEYS = 22;