Ensure transcoding path is created when it is retrieved

MediaBrowser.Common/Configuration/EncodingConfigurationExtensions.cs

@@ -1,3 +1,4 @@
+using System;
 using System.IO;
 using MediaBrowser.Model.Configuration;
 
@@ -17,18 +18,25 @@ namespace MediaBrowser.Common.Configuration
             => configurationManager.GetConfiguration<EncodingOptions>("encoding");
 
         /// <summary>
-        /// Retrieves the transcoding temp path from the encoding configuration.
+        /// Retrieves the transcoding temp path from the encoding configuration, falling back to a default if no path
+        /// is specified in configuration. If the directory does not exist, it will be created.
         /// </summary>
-        /// <param name="configurationManager">The Configuration manager.</param>
+        /// <param name="configurationManager">The configuration manager.</param>
         /// <returns>The transcoding temp path.</returns>
+        /// <exception cref="UnauthorizedAccessException">If the directory does not exist, and the caller does not have the required permission to create it.</exception>
+        /// <exception cref="NotSupportedException">If there is a custom path transcoding path specified, but it is invalid.</exception>
+        /// <exception cref="IOException">If the directory does not exist, and it also could not be created.</exception>
         public static string GetTranscodePath(this IConfigurationManager configurationManager)
         {
+            // Get the configured path and fall back to a default
             var transcodingTempPath = configurationManager.GetEncodingOptions().TranscodingTempPath;
             if (string.IsNullOrEmpty(transcodingTempPath))
             {
-                return Path.Combine(configurationManager.CommonApplicationPaths.ProgramDataPath, "transcodes");
+                transcodingTempPath = Path.Combine(configurationManager.CommonApplicationPaths.ProgramDataPath, "transcodes");
             }
 
+            // Make sure the directory exists
+            Directory.CreateDirectory(transcodingTempPath);
             return transcodingTempPath;
         }
     }