[rygel] engine-gst: Omit transcoder if transcoding for same format

[Jens Georg <jensgeorg src gnome org>]

commit 470accfdb508da2a0d442935e8b149661226c2aa
Author: Jens Georg <mail jensge org>
Date:   Sun May 24 12:56:46 2015 +0200

    engine-gst: Omit transcoder if transcoding for same format
    
    Signed-off-by: Jens Georg <mail jensge org>

 .../gstreamer/rygel-gst-media-engine.vala          |    3 ++-
 .../gstreamer/rygel-gst-transcoder.vala            |   13 +++++++++++++
 2 files changed, 15 insertions(+), 1 deletions(-)
---
diff --git a/src/media-engines/gstreamer/rygel-gst-media-engine.vala 
b/src/media-engines/gstreamer/rygel-gst-media-engine.vala
index 3938498..3dbc6cd 100644
--- a/src/media-engines/gstreamer/rygel-gst-media-engine.vala
+++ b/src/media-engines/gstreamer/rygel-gst-media-engine.vala
@@ -162,7 +162,8 @@ public class Rygel.GstMediaEngine : Rygel.MediaEngine {
 
         var list = new GLib.List<GstTranscoder> ();
         foreach (var transcoder in transcoders) {
-            if (transcoder.get_distance (item) != uint.MAX) {
+            if (transcoder.get_distance (item) != uint.MAX &&
+                transcoder.transcoding_necessary (item)) {
                 list.append (transcoder);
             }
         }
diff --git a/src/media-engines/gstreamer/rygel-gst-transcoder.vala 
b/src/media-engines/gstreamer/rygel-gst-transcoder.vala
index 0ae8199..e94bde2 100644
--- a/src/media-engines/gstreamer/rygel-gst-transcoder.vala
+++ b/src/media-engines/gstreamer/rygel-gst-transcoder.vala
@@ -231,4 +231,17 @@ internal abstract class Rygel.GstTranscoder : GLib.Object {
             bus.post (message);
         }
     }
+
+    public bool transcoding_necessary (MediaFileItem item) {
+        return !(this.mime_type_is_a (this.mime_type, item.mime_type) &&
+                 this.dlna_profile == item.dlna_profile);
+    }
+
+    protected bool mime_type_is_a (string mime_type1, string mime_type2) {
+        string content_type1 = ContentType.get_mime_type (mime_type1);
+        string content_type2 = ContentType.get_mime_type (mime_type2);
+
+        return ContentType.is_a (content_type1, content_type2);
+    }
+
 }