Use static regex

MediaBrowser.MediaEncoding/Encoder/EncoderValidator.cs

@@ -139,9 +139,9 @@ namespace MediaBrowser.MediaEncoding.Encoder
 
             var required = codec == Codec.Encoder ? requiredEncoders : requiredDecoders;
 
-            Regex regex = new Regex(@"^\s\S{6}\s(?<codec>[\w|-]+)\s+.+$", RegexOptions.Multiline);
-            MatchCollection matches = regex.Matches(output);
-            var found = matches.Cast<Match>()
+            var found = Regex
+                .Matches(output, @"^\s\S{6}\s(?<codec>[\w|-]+)\s+.+$", RegexOptions.Multiline)
+                .Cast<Match>()
                 .Select(x => x.Groups["codec"].Value)
                 .Where(x => required.Contains(x));