Update pipeline.py

pipeline.py

@@ -1021,8 +1021,12 @@ class AnimateDiffPipeline(DiffusionPipeline, TextualInversionLoaderMixin, IPAdap
                     context_group_indexes = []
                     # Iterate over each index in the context group
                     for index in range(context_size):
-                        # Calculate the frame index
-                        frame_index = (group_index * (context_size - overlap)) + (offset * timestep) + index
+                        # if its the first timestep, spread the indexes out evenly over the full frame range, offset by the group index
+                        if timestep == 0:
+                            frame_index = (group_index * (context_size - overlap)) + index
+                        else:
+                            # Calculate the frame index
+                            frame_index = (group_index * (context_size - overlap)) + (offset * timestep) + index
                         # If frame index exceeds total frames, wrap around
                         if frame_index >= total_frames:
                             frame_index %= total_frames