diff --git a/openbr/plugins/frames.cpp b/openbr/plugins/frames.cpp
index 440d36f..18d7b94 100644
--- a/openbr/plugins/frames.cpp
+++ b/openbr/plugins/frames.cpp
@@ -58,35 +58,21 @@ BR_REGISTER(Transform, AggregateFrames)
  *
  * For a video with m frames, DropFrames will pass on m/n frames.
  */
-class DropFrames : public TimeVaryingTransform
+class DropFrames : public UntrainableMetaTransform
 {
     Q_OBJECT
     Q_PROPERTY(int n READ get_n WRITE set_n RESET reset_n STORED false)
     BR_PROPERTY(int, n, 1)
 
-public:
-    DropFrames() : TimeVaryingTransform(false) {}
-
-private:
-    void train(const TemplateList &data)
-    {
-        (void) data;
-    }
-
-    void projectUpdate(const Template &src, Template &dst)
+    void project(const TemplateList &src, TemplateList &dst) const
     {
-        if (src.file.get<int>("FrameNumber") % n != 0) return;
+        if (src.first().file.get<int>("FrameNumber") % n != 0) return;
         dst = src;
     }
 
-    void store(QDataStream &stream) const
-    {
-        (void) stream;
-    }
-
-    void load(QDataStream &stream)
+    void project(const Template &src, Template &dst) const
     {
-        (void) stream;
+        (void) src; (void) dst; qFatal("shouldn't be here");
     }
 };