New: Don't try to analyze disk image files (iso, img, etc)

Closes #5567

src/NzbDrone.Core/MediaFiles/MediaInfo/VideoFileInfoReader.cs

@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using FFMpegCore;
+using FFMpegCore.Enums;
 using NLog;
 using NzbDrone.Common.Disk;
 using NzbDrone.Common.Extensions;
@@ -55,6 +56,11 @@ namespace NzbDrone.Core.MediaFiles.MediaInfo
                 throw new FileNotFoundException("Media file does not exist: " + filename);
             }
 
+            if (MediaFileExtensions.DiskExtensions.Contains(Path.GetExtension(filename)))
+            {
+                return null;
+            }
+
             // TODO: Cache media info by path, mtime and length so we don't need to read files multiple times
 
             try