Update app.py

app.py

@@ -118,6 +118,49 @@ def prepare_video_and_mask_FLF2V(first_img: Image.Image, last_img: Image.Image,
     mask = [mask_black, *[mask_white] * (num_frames - 2), mask_black]
     return frames, mask
 
+def calculate_random2v_frame_indices(num_images: int, num_frames: int) -> List[int]:
+    """
+    Calculate evenly spaced frame indices for Random2V mode.
+    
+    Args:
+        num_images (int): Number of input images
+        num_frames (int): Total number of frames in the video
+    
+    Returns:
+        List[int]: Frame indices where images should be placed
+    """
+    if num_images <= 0:
+        return []
+    
+    if num_images == 1:
+        # Single image goes in the middle
+        return [num_frames // 2]
+    
+    if num_images >= num_frames:
+        # More images than frames, use every frame
+        return list(range(num_frames))
+    
+    # Calculate evenly spaced indices
+    # We want to distribute images across the full duration
+    indices = []
+    step = (num_frames - 1) / (num_images - 1)
+    
+    for i in range(num_images):
+        frame_idx = int(round(i * step))
+        # Ensure we don't exceed num_frames - 1
+        frame_idx = min(frame_idx, num_frames - 1)
+        indices.append(frame_idx)
+    
+    # Remove duplicates while preserving order
+    seen = set()
+    unique_indices = []
+    for idx in indices:
+        if idx not in seen:
+            seen.add(idx)
+            unique_indices.append(idx)
+    
+    return unique_indices
+
 def prepare_video_and_mask_Random2V(images: List[Image.Image], frame_indices: List[int], height: int, width: int, num_frames: int):
     images = [img.resize((width, height)) for img in images]
     # Ideally, this should be 127.5 to match original code, but they perform computation on numpy arrays
@@ -205,10 +248,12 @@ def generate_video(gallery_images, mode, prompt, height, width,
         frames, mask = prepare_video_and_mask_Ref2V(height=target_h, width=target_w, num_frames=num_frames)
         reference_images = gallery_images
     else:  # mode == "Random2V"
+        # Calculate dynamic frame indices based on number of images and frames
+        frame_indices = calculate_random2v_frame_indices(len(gallery_images), num_frames)
         
         frames, mask = prepare_video_and_mask_Random2V(
             images=gallery_images, 
-            frame_indices=[0,20,40], # todo - generalize
+            frame_indices=frame_indices,
             height=target_h, 
             width=target_w, 
             num_frames=num_frames