Merge pull request #2715 from nyanmisaka/libfdk-aac

Prefer to use libfdk_aac encoder for better audio quality when it is available

(cherry picked from commit bf92694f8b)
Signed-off-by: Joshua M. Boniface <joshua@boniface.me>

MediaBrowser.Controller/MediaEncoding/EncodingHelper.cs

@@ -406,7 +406,13 @@ namespace MediaBrowser.Controller.MediaEncoding
 
             if (string.Equals(codec, "aac", StringComparison.OrdinalIgnoreCase))
             {
-                return "aac -strict experimental";
+                // Use libfdk_aac for better audio quality if using custom build of FFmpeg which has fdk_aac support
+                if (_mediaEncoder.SupportsEncoder("libfdk_aac"))
+                {
+                    return "libfdk_aac";
+                }
+
+                return "aac";
             }
 
             if (string.Equals(codec, "mp3", StringComparison.OrdinalIgnoreCase))

MediaBrowser.MediaEncoding/Encoder/EncoderValidator.cs

@@ -42,6 +42,7 @@ namespace MediaBrowser.MediaEncoding.Encoder
             "libvpx",
             "libvpx-vp9",
             "aac",
+            "libfdk_aac",
             "libmp3lame",
             "libopus",
             "libvorbis",