video: fix null codec

Change-Id: I6f17fdb126088c2a395a3a965bbd581a70f8bd84
diff --git a/ring-android/app/src/main/java/cx/ring/services/CameraService.java b/ring-android/app/src/main/java/cx/ring/services/CameraService.java
index 7ec0a31..a660c78 100644
--- a/ring-android/app/src/main/java/cx/ring/services/CameraService.java
+++ b/ring-android/app/src/main/java/cx/ring/services/CameraService.java
@@ -187,6 +187,8 @@
         }
 
         public String getCodec() {
+            if (codec == null)
+                return MediaFormat.MIMETYPE_VIDEO_AVC;
             switch (codec) {
                 case "H264": return MediaFormat.MIMETYPE_VIDEO_AVC;
                 case "H265": return MediaFormat.MIMETYPE_VIDEO_HEVC;