diff --git a/lib/RippingCluster/BackgroundTask.class.php b/lib/RippingCluster/BackgroundTask.class.php
index 61a139c..dc4cb45 100644
--- a/lib/RippingCluster/BackgroundTask.class.php
+++ b/lib/RippingCluster/BackgroundTask.class.php
@@ -6,7 +6,7 @@ class RippingCluster_BackgroundTask {
         
     }
 
-    public function run($command) {
+    public static function run($command) {
         $pipes = array();
         $pid = proc_open($command . ' &', array(), $pipes);
         proc_close($pid);
diff --git a/lib/RippingCluster/ForegroundTask.class.php b/lib/RippingCluster/ForegroundTask.class.php
index 597b636..059a707 100644
--- a/lib/RippingCluster/ForegroundTask.class.php
+++ b/lib/RippingCluster/ForegroundTask.class.php
@@ -59,7 +59,9 @@ class RippingCluster_ForegroundTask {
                 $tx[] = $pipes[self::PIPE_STDIN];
             }
             
-            stream_select($rx, $tx, $ex = null, null, null); // Block til r/w possible
+            $ex = array();
+            
+            stream_select($rx, $tx, $ex, null, null); // Block til r/w possible
             if (!empty($tx)) {
                 $txRet = fwrite($pipes[self::PIPE_STDIN], substr($stdin, $txOff, 8192));
                 if ($txRet !== false) {
diff --git a/lib/RippingCluster/IPlugin.class.php b/lib/RippingCluster/IPlugin.class.php
new file mode 100644
index 0000000..35cd7f4
--- /dev/null
+++ b/lib/RippingCluster/IPlugin.class.php
@@ -0,0 +1,11 @@
+<?php
+
+interface RippingCluster_IPlugin {
+    
+    public static function init();
+    
+    public static function name();
+    
+}
+
+?>
\ No newline at end of file
diff --git a/lib/RippingCluster/IPluginFactory.class.php b/lib/RippingCluster/IPluginFactory.class.php
new file mode 100644
index 0000000..94c4aa6
--- /dev/null
+++ b/lib/RippingCluster/IPluginFactory.class.php
@@ -0,0 +1,9 @@
+<?php
+
+interface RippingCluster_IPluginFactory {
+
+    public static function init();
+    
+}
+
+?>
\ No newline at end of file
diff --git a/lib/RippingCluster/PluginFactory.class.php b/lib/RippingCluster/PluginFactory.class.php
index 595392c..3827162 100644
--- a/lib/RippingCluster/PluginFactory.class.php
+++ b/lib/RippingCluster/PluginFactory.class.php
@@ -1,13 +1,22 @@
 <?php
 
-abstract class RippingCluster_PluginFactory {
+abstract class RippingCluster_PluginFactory implements RippingCluster_IPluginFactory {
     
-    static protected $validPlugins;
+    static private $validPlugins = array();
     
-    abstract public static function init();
+    protected static function ensureScanned() {
+        if (! isset(self::$validPlugins[get_called_class()])) {
+            static::scan();
+        }
+    }
+    
+    protected static function isValidPlugin($plugin) {
+        return isset(self::$validPlugins[get_called_class()][$plugin]);
+    }
     
     public static function getValidPlugins() {
-        return array_keys(self::$validPlugins);
+        static::ensureScanned();
+        return array_keys(self::$validPlugins[get_called_class()]);
     }
     
     protected static function findPlugins($directory) {
@@ -23,28 +32,36 @@ abstract class RippingCluster_PluginFactory {
         return $plugins;
     }
     
-    protected static function loadPlugins($plugins, $prefix) {
-        self::$validPlugins = array();
+    protected static function loadPlugins($plugins, $prefix, $interface) {
+        self::$validPlugins[get_called_class()] = array();
         
         foreach ($plugins as $plugin) {
             $fullClassname = $prefix . $plugin;
             if ( ! class_exists($fullClassname, true)) {
-                echo "Cannot load $fullClassname\n";
                 continue;
             }
             
-            if ( ! in_array('RippingCluster_Worker_IPlugin', class_implements($fullClassname))) {
-                echo "$plugin does not implement the necessary interfaces\n";
+            if ( ! in_array($interface, class_implements($fullClassname))) {
                 continue;
             }
             
             // Initialise the plugin
             call_user_func(array($fullClassname, 'init'));
         
-            self::$validPlugins[$plugin] = $fullClassname;
+            self::$validPlugins[get_called_class()][$plugin] = $fullClassname;
         }
     }
     
+    public static function classname($plugin) {
+        static::ensureScanned();
+        
+        if ( ! self::isValidPlugin($plugin)) {
+            throw new RippingCluster_Exception_InvalidPluginName($plugin);
+        }
+        
+        return self::$validPlugins[get_called_class()][$plugin];
+    }
+    
 }
 
 ?>
\ No newline at end of file
diff --git a/lib/RippingCluster/Source/IPlugin.class.php b/lib/RippingCluster/Source/IPlugin.class.php
new file mode 100644
index 0000000..72f8b47
--- /dev/null
+++ b/lib/RippingCluster/Source/IPlugin.class.php
@@ -0,0 +1,15 @@
+<?php
+
+interface RippingCluster_Source_IPlugin extends RippingCluster_IPlugin {
+    
+    public static function enumerate();
+    
+    public static function load($source_filename, $scan = true, $use_cache = true);
+    
+    public static function loadEncoded($encoded_filename, $scan = true, $use_cache = true);
+    
+    public static function isValidSource($source);
+    
+}
+
+?>
\ No newline at end of file
diff --git a/lib/RippingCluster/Source/PluginFactory.class.php b/lib/RippingCluster/Source/PluginFactory.class.php
new file mode 100644
index 0000000..0f385c3
--- /dev/null
+++ b/lib/RippingCluster/Source/PluginFactory.class.php
@@ -0,0 +1,41 @@
+<?php
+
+class RippingCluster_Source_PluginFactory extends RippingCluster_PluginFactory {
+    
+    const PLUGIN_DIR       = 'RippingCluster/Source/Plugin/';
+    const PLUGIN_PREFIX    = 'RippingCluster_Source_Plugin_';
+    const PLUGIN_INTERFACE = 'RippingCluster_Source_IPlugin';
+    
+    public static function init() {
+        
+    }
+    
+    public static function scan() {
+        $candidatePlugins   = parent::findPlugins(self::PLUGIN_DIR);
+        
+        self::loadPlugins($candidatePlugins, self::PLUGIN_PREFIX, self::PLUGIN_INTERFACE);
+    }
+    
+    public static function load($plugin, $source_filename, $scan = true, $use_cache = true) {
+        self::ensureScanned();
+        
+        if ( ! self::isValidPlugin($plugin)) {
+            return null;
+        }
+        
+        return call_user_func(array(self::classname($plugin), 'load'), $source_filename, $scan, $use_cache);
+    }
+    
+    public static function loadEncoded($plugin, $encoded_filename, $scan = true, $use_cache = true) {
+        self::ensureScanned();
+        
+        if ( ! self::isValidPlugin($plugin)) {
+            return null;
+        }
+        
+        return call_user_func(array(self::classname($plugin), 'loadEncoded'), $encoded_filename, $scan, $use_cache);
+    }
+    
+}
+
+?>
\ No newline at end of file
diff --git a/lib/RippingCluster/Worker/IPlugin.class.php b/lib/RippingCluster/Worker/IPlugin.class.php
index 25afefc..252d37c 100644
--- a/lib/RippingCluster/Worker/IPlugin.class.php
+++ b/lib/RippingCluster/Worker/IPlugin.class.php
@@ -1,10 +1,6 @@
 <?php
 
-interface RippingCluster_Worker_IPlugin {
-    
-    public static function init();
-    
-    public static function name();
+interface RippingCluster_Worker_IPlugin extends RippingCluster_IPlugin {
     
     public static function workerFunctions();
 
diff --git a/lib/RippingCluster/Worker/PluginFactory.class.php b/lib/RippingCluster/Worker/PluginFactory.class.php
index 7646406..21afcaa 100644
--- a/lib/RippingCluster/Worker/PluginFactory.class.php
+++ b/lib/RippingCluster/Worker/PluginFactory.class.php
@@ -2,8 +2,9 @@
 
 class RippingCluster_Worker_PluginFactory extends RippingCluster_PluginFactory {
     
-    const PLUGIN_DIR = 'RippingCluster/Worker/Plugin/';
-    const PREFIX     = 'RippingCluster_Worker_Plugin_';
+    const PLUGIN_DIR       = 'RippingCluster/Worker/Plugin/';
+    const PLUGIN_PREFIX    = 'RippingCluster_Worker_Plugin_';
+    const PLUGIN_INTERFACE = 'RippingCluster_Worker_IPlugin';
     
     public static function init() {
         
@@ -12,15 +13,15 @@ class RippingCluster_Worker_PluginFactory extends RippingCluster_PluginFactory {
     public static function scan() {
         $candidatePlugins   = parent::findPlugins(self::PLUGIN_DIR);
         
-        parent::loadPlugins($candidatePlugins, self::PREFIX);
+        parent::loadPlugins($candidatePlugins, self::PLUGIN_PREFIX, self::PLUGIN_INTERFACE);
     }
     
     public static function getPluginWorkerFunctions($plugin) {
-        if ( ! isset(parent::$validPlugins[$plugin])) {
+        if ( ! self::isValidPlugin($plugin)) {
             return null;
         }
         
-        return call_user_func(array(parent::$validPlugins[$plugin], 'workerFunctions'));
+        return call_user_func(array(self::classname($plugin), 'workerFunctions'));
     }
 }