Fixed frames sometimes not showing up

Better return true here, since there is a frame available which can be shown

Vocaluxe/Lib/Video/Acinerella/CDecoder.cs

@@ -130,7 +130,7 @@ namespace Vocaluxe.Lib.Video.Acinerella
             else
             {
                 videoTime = 0;
-                return false;
+                return true;
             }
             _UploadNewFrame(ref frame);
             videoTime = _LastShownTime;
@@ -438,4 +438,4 @@ namespace Vocaluxe.Lib.Video.Acinerella
         }
         #endregion Threading
     }
-}
+}