diff --git a/tsmark/video_annotator.py b/tsmark/video_annotator.py
index 049b493..c803cb2 100755
--- a/tsmark/video_annotator.py
+++ b/tsmark/video_annotator.py
@@ -55,10 +55,10 @@ class Marker:
         self.forced_fps = opts.fps
 
         try:
-            self.load_plugin()
             self.open()
             self.calculate_res()
             self.parse_timestamps()
+            self.load_plugin()
             if self.opts.start_time:
                 try:
                     self.nr = int(self.opts.start_time)
@@ -615,7 +615,7 @@ class World:
         if self.plugin:
             self.plugin(self)
 
-    def interpolate_points(self):
+    def interpolate_points(self, point_index = None):
         """types:
         key:  user clicked / accepted frame
         interp: interpolated frame
@@ -623,6 +623,9 @@ class World:
         post: after any keyframes
         """
 
+        if point_index is None:
+            point_index = self.point_index
+
         def i_point(x0=None, y0=None, x1=None, y1=None, t=None, visible=None, age=None):
             return {"x0": x0, "y0": y0, "x1": x1, "y1": y1, "type": t, "visible": visible, "age"=age}
 
@@ -630,23 +633,25 @@ class World:
 
             return [p["x0"], p["y0"], p["x1"], p["y1"]]
 
-        if not self.point_index in self.points_interpolated:
-            self.points_interpolated[self.point_index] = {key: {} for key in range(self.frames)}
+        if not point_index in self.points:
+            return
 
-        if len(self.points[self.point_index]) == 1:  # only one point added
-            key = list(self.points[self.point_index].keys())[0]
-            vals = self.points[self.point_index][key]
-            # x, y, x2, y2 = self.points[self.point_index][key]
+        if not point_index in self.points_interpolated:
+            self.points_interpolated[point_index] = {key: {} for key in range(self.frames)}
+
+        if len(self.points[point_index]) == 1:  # only one point added
+            key = list(self.points[point_index].keys())[0]
+            vals = self.points[point_index][key]
             for key in range(self.frames):
-                self.points_interpolated[self.point_index][key] = i_point()
-                self.points_interpolated[self.point_index][key].update(vals)
-                self.points_interpolated[self.point_index][key]["type"] = "pre"
+                self.points_interpolated[point_index][key] = i_point()
+                self.points_interpolated[point_index][key].update(vals)
+                self.points_interpolated[point_index][key]["type"] = "pre"
 
-            self.points_interpolated[self.point_index][self.nr]["type"] = "key"
+            self.points_interpolated[point_index][self.nr]["type"] = "key"
 
         else:  # more points
-            point_keys = list(sorted(list(self.points[self.point_index].keys())))
-            point_values = [point2array(self.points[self.point_index][k]) for k in point_keys]
+            point_keys = list(sorted(list(self.points[point_index].keys())))
+            point_values = [point2array(self.points[point_index][k]) for k in point_keys]
             xyxy = np.array(point_values).T
             spline = PchipInterpolator(point_keys, xyxy, axis=1)
             start_key = min(point_keys)
@@ -654,14 +659,14 @@ class World:
             t2 = np.arange(start_key, end_key)
             # Pre points
             for key in range(0, start_key):
-                self.points_interpolated[self.point_index][key]["type"] = "pre"
-                self.points_interpolated[self.point_index][key].update(self.points[self.point_index][start_key])
+                self.points_interpolated[point_index][key]["type"] = "pre"
+                self.points_interpolated[point_index][key].update(self.points[point_index][start_key])
             # interpolated points
-            visible = self.points[self.point_index][start_key]["visible"]
+            visible = self.points[point_index][start_key]["visible"]
             for row in np.vstack((t2, spline(t2))).T:
                 if row[0] in point_keys:
-                    visible = self.points[self.point_index][row[0]]["visible"]
-                self.points_interpolated[self.point_index][row[0]] = {
+                    visible = self.points[point_index][row[0]]["visible"]
+                self.points_interpolated[point_index][row[0]] = {
                     "type": "interp",
                     "x0": int(row[1]),
                     "y0": int(row[2]),
@@ -672,7 +677,7 @@ class World:
 
             # post points
             for key in range(end_key, self.frames + 1):
-                self.points_interpolated[self.point_index][key] = {
+                self.points_interpolated[point_index][key] = {
                     "type": "post",
                     "x0": int(row[1]),
                     "y0": int(row[2]),
@@ -682,14 +687,14 @@ class World:
                 }
             # clicked points (not necessary, could determine at draw time!)
             for key in point_keys:
-                self.points_interpolated[self.point_index][key]["type"] = "key"
+                self.points_interpolated[point_index][key]["type"] = "key"
             age=0
-            for key in self.points_interpolated[self.point_index]:
-                if self.points_interpolated[self.point_index][key]["type"] == "key":
+            for key in self.points_interpolated[point_index]:
+                if self.points_interpolated[point_index][key]["type"] == "key":
                     age = 0
-                if self.points_interpolated[self.point_index][key]["type"] == "interp":
+                if self.points_interpolated[point_index][key]["type"] == "interp":
                     age += 1
-                    self.points_interpolated[self.point_index][key]["type"] = age
+                    self.points_interpolated[point_index][key]["type"] = age
 
     def draw_help(self, frame):