use existing font when possible

MediaBrowser.Server.Implementations/MediaEncoder/MediaEncoder.cs

@@ -236,6 +236,32 @@ namespace MediaBrowser.Server.Implementations.MediaEncoder
 
             if (!File.Exists(fontFile))
             {
+                await DownloadFontFile(fontsDirectory, fontFilename).ConfigureAwait(false);
+            }
+
+            await WriteFontConfigFile(fontsDirectory).ConfigureAwait(false);
+        }
+
+        private async Task DownloadFontFile(string fontsDirectory, string fontFilename)
+        {
+            var existingFile = Directory
+                .EnumerateFiles(_appPaths.ProgramDataPath, fontFilename, SearchOption.AllDirectories)
+                .FirstOrDefault();
+
+            if (existingFile != null)
+            {
+                try
+                {
+                    File.Copy(existingFile, Path.Combine(fontsDirectory, fontFilename), true);
+                    return;
+                }
+                catch (IOException ex)
+                {
+                    // Log this, but don't let it fail the operation
+                    _logger.ErrorException("Error copying file", ex);
+                }
+            }
+
             var tempFile = await _httpClient.GetTempFile(new HttpRequestOptions
             {
                 Url = FontUrl,
@@ -255,9 +281,6 @@ namespace MediaBrowser.Server.Implementations.MediaEncoder
             }
         }
 
-            await WriteFontConfigFile(fontsDirectory).ConfigureAwait(false);
-        }
-
         private async Task WriteFontConfigFile(string fontsDirectory)
         {
             const string fontConfigFilename = "fonts.conf";