[rygel] Transcoder: Document add_resource()

[Murray Cumming <murrayc src gnome org>]

commit aea54b330d3d845dbbbdefa0b9562dbe15feecac
Author: Murray Cumming <murrayc murrayc com>
Date:   Wed Jan 23 11:09:10 2013 +0100

    Transcoder: Document add_resource()

 src/librygel-server/rygel-transcoder.vala |   15 +++++++++++++++
 1 files changed, 15 insertions(+), 0 deletions(-)
---
diff --git a/src/librygel-server/rygel-transcoder.vala b/src/librygel-server/rygel-transcoder.vala
index 439997c..fcaab7b 100644
--- a/src/librygel-server/rygel-transcoder.vala
+++ b/src/librygel-server/rygel-transcoder.vala
@@ -54,6 +54,21 @@ public abstract class Rygel.Transcoder : GLib.Object {
     public abstract DataSource create_source (MediaItem  item,
                                               DataSource src) throws Error;
 
+    //TODO: It would be simpler for this to take a DIDLLiteResource to be filled,
+    //rather than taking a didl_item, requiring the call of the base class, and then
+    //returning the DIDLLiteResource.
+    /**
+     * Derived classes should implement this function to fill a GUPnPDIDLLiteResource,
+     * representing the transcoded content, with parameters specific to the transcoder,
+     * such as bitrate or resolution. The GUPnPDIDLLiteResource should be instantiated
+     * by calling this base class implementation, passing the provided didl_item, item
+     * and manager parameters.
+     *
+     * @param didl_item The DIDLLite item for which to create the resource, by calling the base class implementation.
+     * @param item The media item for which to create the DIDLiteResource, by calling the base class implementation.
+     * @param manager The transcoder manager to pass to the base class implemenetation.
+     * @return The new resource.
+     */
     public virtual DIDLLiteResource? add_resource (DIDLLiteItem     didl_item,
                                                    MediaItem        item,
                                                    TranscodeManager manager)