[rygel] core: Add Transcoder.get_distance()

[Zeeshan Ali Khattak <zeeshanak src gnome org>]

commit 3b1b7d88286bc0682c76203b62a38b19e26b60a8
Author: Zeeshan Ali (Khattak) <zeeshanak gnome org>
Date:   Mon Jul 6 18:07:59 2009 +0300

    core: Add Transcoder.get_distance()
    
    Add a method to Transcoder classes that returns a the numeric value that
    gives an estimate of how hard would it be to trancode @item to target
    profile of this transcoder.

 src/rygel/rygel-l16-transcoder.vala   |   24 ++++++++++++++++++++++++
 src/rygel/rygel-mp2ts-transcoder.vala |   24 ++++++++++++++++++++++++
 src/rygel/rygel-mp3-transcoder.vala   |   14 ++++++++++++++
 src/rygel/rygel-transcoder.vala       |   12 ++++++++++++
 4 files changed, 74 insertions(+), 0 deletions(-)
---
diff --git a/src/rygel/rygel-l16-transcoder.vala b/src/rygel/rygel-l16-transcoder.vala
index baeac4a..f534fd8 100644
--- a/src/rygel/rygel-l16-transcoder.vala
+++ b/src/rygel/rygel-l16-transcoder.vala
@@ -82,6 +82,30 @@ internal class Rygel.L16Transcoder : Rygel.Transcoder {
         return resource;
     }
 
+    public override uint get_distance (MediaItem item) {
+        if (item.upnp_class.has_prefix (MediaItem.IMAGE_CLASS)) {
+            return uint.MAX;
+        }
+
+        uint distance = uint.MIN;
+
+        if (item.upnp_class.has_prefix (MediaItem.MUSIC_CLASS)) {
+            if (item.sample_freq > 0) {
+                distance += (item.sample_freq - FREQUENCY).abs ();
+            }
+
+            if (item.n_audio_channels > 0) {
+                distance += (item.n_audio_channels - CHANNELS).abs ();
+            }
+
+            if (item.bits_per_sample > 0) {
+                distance += (item.bits_per_sample - WIDTH).abs ();
+            }
+        }
+
+        return distance;
+    }
+
     public Element create_encoder (MediaItem item,
                                    string?   src_pad_name,
                                    string?   sink_pad_name)
diff --git a/src/rygel/rygel-mp2ts-transcoder.vala b/src/rygel/rygel-mp2ts-transcoder.vala
index e42bc98..769b966 100644
--- a/src/rygel/rygel-mp2ts-transcoder.vala
+++ b/src/rygel/rygel-mp2ts-transcoder.vala
@@ -76,6 +76,30 @@ internal class Rygel.MP2TSTranscoder : Rygel.Transcoder {
         return resource;
     }
 
+    public override uint get_distance (MediaItem item) {
+        if (item.upnp_class.has_prefix (MediaItem.IMAGE_CLASS)) {
+            return uint.MAX;
+        }
+
+        uint distance = uint.MIN;
+
+        if (item.upnp_class.has_prefix (MediaItem.VIDEO_CLASS)) {
+            if (item.bitrate > 0) {
+                distance += (item.bitrate - BITRATE).abs ();
+            }
+
+            if (item.width > 0) {
+                distance += (item.width - WIDTH[this.profile]).abs ();
+            }
+
+            if (item.height > 0) {
+                distance += (item.height - HEIGHT[this.profile]).abs ();
+            }
+        }
+
+        return distance;
+    }
+
     public Element create_encoder (MediaItem item,
                                    string?   src_pad_name,
                                    string?   sink_pad_name)
diff --git a/src/rygel/rygel-mp3-transcoder.vala b/src/rygel/rygel-mp3-transcoder.vala
index e059d76..da68384 100644
--- a/src/rygel/rygel-mp3-transcoder.vala
+++ b/src/rygel/rygel-mp3-transcoder.vala
@@ -64,6 +64,20 @@ internal class Rygel.MP3Transcoder : Rygel.Transcoder {
         return resource;
     }
 
+    public override uint get_distance (MediaItem item) {
+        if (item.upnp_class.has_prefix (MediaItem.IMAGE_CLASS)) {
+            return uint.MAX;
+        }
+
+        uint distance = uint.MIN;
+
+        if (item.bitrate > 0) {
+            distance += (item.bitrate - BITRATE).abs ();
+        }
+
+        return distance;
+    }
+
     public Element create_encoder (MediaItem item,
                                    string?   src_pad_name,
                                    string?   sink_pad_name)
diff --git a/src/rygel/rygel-transcoder.vala b/src/rygel/rygel-transcoder.vala
index b136c79..5015f1b 100644
--- a/src/rygel/rygel-transcoder.vala
+++ b/src/rygel/rygel-transcoder.vala
@@ -85,6 +85,18 @@ internal abstract class Rygel.Transcoder : GLib.Object {
         return target == this.dlna_profile;
     }
 
+    /**
+     * Gets the numeric value that gives an gives an estimate of how hard
+     * would it be to trancode @item to target profile of this transcoder.
+     *
+     * @param item the media item to calculate the distance for
+     *
+     * @return      the distance from the @item, uint.MIN if providing such a
+     *              value is impossible or uint.MAX if it doesn't make any
+     *              sense to use this transcoder for @item
+     */
+    public abstract uint get_distance (MediaItem item);
+
     protected bool mime_type_is_a (string mime_type1,
                                           string mime_type2) {
         string content_type1 = g_content_type_from_mime_type (mime_type1);