diff --git a/management/commands/generate_clips.py b/management/commands/generate_clips.py
index 270c6bd..94098cc 100644
--- a/management/commands/generate_clips.py
+++ b/management/commands/generate_clips.py
@@ -52,6 +52,9 @@ class Command(BaseCommand):
                     clip[type_] = target
                     durations.append(e.files.filter(selected=True)[0].duration)
                 clip["duration"] = min(durations)
+                if not clip["duration"]:
+                    print('!!', durations, clip)
+                    continue
                 clip['tags'] = i.data.get('tags', [])
                 clip['editingtags'] = i.data.get('editingtags', [])
                 name = os.path.basename(clip['original'])
diff --git a/render.py b/render.py
index d603f04..db35c72 100644
--- a/render.py
+++ b/render.py
@@ -308,12 +308,12 @@ def render_all(options):
 
         scene = compose(fragment['clips'], target=target, base=base, voice_over=fragment['voice_over'])
         scene_duration = get_scene_duration(scene)
-        print("%s %s -> %s (%s)" % (name, target, scene_duration, fragment_target))
+        print("%s %6.3f -> %6.3f (%6.3f)" % (name, target, scene_duration, fragment_target))
         position += scene_duration
         target_position += fragment_target
         if position > target_position:
             target = fragment_target - (position-target_position)
-            print("adjusting target from", fragment_target, target)
+            print("adjusting target duration for next fragment: %6.3f -> %6.3f" % (fragment_target, target))
         elif position < target_position:
             target = target + 0.1 * fragment_target