Replace imageio with OpenCV for video saving in generate.py; updated default frame count to 100.

mlx_video/generate.py

@@ -276,8 +276,13 @@ def generate_video(
     output_path.parent.mkdir(parents=True, exist_ok=True)
 
     try:
-        import imageio
+        import cv2
-        imageio.mimwrite(str(output_path), video_np, fps=fps, codec='libx264')
+        height, width = video_np.shape[1], video_np.shape[2]
+        fourcc = cv2.VideoWriter_fourcc(*'avc1')
+        out = cv2.VideoWriter(str(output_path), fourcc, fps, (width, height))
+        for frame in video_np:
+            out.write(cv2.cvtColor(frame, cv2.COLOR_RGB2BGR))
+        out.release()
         print(f"Saved video to {output_path}")
     except Exception as e:
         print(f"Could not save video: {e}")
@@ -328,8 +333,8 @@ Examples:
     parser.add_argument(
         "--num-frames", "-n",
         type=int,
-        default=33,
+        default=100,
-        help="Number of frames (default: 33, must be 1 + 8*k)"
+        help="Number of frames (default: 100)"
     )
     parser.add_argument(
         "--seed", "-s",