fixes #238 - MBServer Client Theme Background

MediaBrowser.Controller/Providers/MediaInfo/FFProbeAudioInfoProvider.cs

@@ -44,8 +44,10 @@ namespace MediaBrowser.Controller.Providers.MediaInfo
                 .ToList();
 
             // Get the first audio stream
-            var stream = data.streams.First(s => s.codec_type.Equals("audio", StringComparison.OrdinalIgnoreCase));
+            var stream = data.streams.FirstOrDefault(s => s.codec_type.Equals("audio", StringComparison.OrdinalIgnoreCase));
 
+            if (stream != null)
+            {
                 // Get duration from stream properties
                 var duration = stream.duration;
 
@@ -60,6 +62,7 @@ namespace MediaBrowser.Controller.Providers.MediaInfo
                 {
                     audio.RunTimeTicks = TimeSpan.FromSeconds(double.Parse(duration, UsCulture)).Ticks;
                 }
+            }
 
             if (data.format.tags != null)
             {