install sam2 the way facebook says

vr180_matting/config.py

@@ -27,8 +27,8 @@ class MattingConfig:
     use_disparity_mapping: bool = True
     memory_offload: bool = True
     fp16: bool = True
-    sam2_model_cfg: str = "sam2_hiera_l"
-    sam2_checkpoint: str = "sam2_hiera_large.pt"
+    sam2_model_cfg: str = "sam2.1_hiera_l"
+    sam2_checkpoint: str = "segment-anything-2/checkpoints/sam2.1_hiera_large.pt"
 
 
 @dataclass

vr180_matting/main.py

@@ -111,6 +111,8 @@ matting:
   use_disparity_mapping: true
   memory_offload: true
   fp16: true
+  sam2_model_cfg: "sam2.1_hiera_l"
+  sam2_checkpoint: "segment-anything-2/checkpoints/sam2.1_hiera_large.pt"
   
 output:
   path: "path/to/output/"

vr180_matting/sam2_wrapper.py

@@ -39,18 +39,23 @@ class SAM2VideoMatting:
     def _load_model(self, model_cfg: str, checkpoint_path: str):
         """Load SAM2 video predictor with optimizations"""
         try:
-            # Check for checkpoint in models directory if not found
+            # Check for checkpoint in SAM2 repo structure
             if not Path(checkpoint_path).exists():
-                models_path = Path("models") / checkpoint_path
-                if models_path.exists():
-                    checkpoint_path = str(models_path)
+                # Try in segment-anything-2/checkpoints/
+                sam2_path = Path("segment-anything-2/checkpoints") / Path(checkpoint_path).name
+                if sam2_path.exists():
+                    checkpoint_path = str(sam2_path)
                 else:
-                    # Try relative to package
-                    import os
-                    package_dir = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
-                    models_path = Path(package_dir) / "models" / checkpoint_path
+                    # Try legacy models/ directory
+                    models_path = Path("models") / Path(checkpoint_path).name
                     if models_path.exists():
                         checkpoint_path = str(models_path)
+                    else:
+                        # Try relative to package
+                        package_dir = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+                        sam2_repo_path = Path(package_dir) / "segment-anything-2/checkpoints" / Path(checkpoint_path).name
+                        if sam2_repo_path.exists():
+                            checkpoint_path = str(sam2_repo_path)
             
             self.predictor = build_sam2_video_predictor(
                 model_cfg,