fix video loading and error

lib/src/message_widget.dart

@@ -1038,8 +1038,12 @@ class _MessageWidgetState extends State<MessageWidget>
       future: videoController.initialize(),
       builder: (_, snapshot) {
         if (snapshot.connectionState != ConnectionState.done) {
-          return Center(
+          return Container(
+            height: 100,
+            width: 100,
+            child: Center(
               child: CircularProgressIndicator(),
+            ),
           );
         }
         ChewieController chewieController;
@@ -1052,6 +1056,7 @@ class _MessageWidgetState extends State<MessageWidget>
               autoInitialize: false,
               aspectRatio: videoController.value.aspectRatio,
               errorBuilder: (_, e) {
+                if (attachment.thumbUrl != null) {
                   return Stack(
                     children: <Widget>[
                       Container(
@@ -1064,6 +1069,7 @@ class _MessageWidgetState extends State<MessageWidget>
                           ),
                         ),
                       ),
+                      if (attachment.titleLink != null)
                         Material(
                           color: Colors.transparent,
                           child: InkWell(
@@ -1072,6 +1078,9 @@ class _MessageWidgetState extends State<MessageWidget>
                         ),
                     ],
                   );
+                }
+
+                return _buildErrorImage(attachment);
               });
           _chuwieControllers[attachment.assetUrl] = chewieController;
         }