Add auto_pyr_level toggle to select pyramid level by resolution

When enabled (default), automatically picks the optimal pyr_level
based on input height: <540p=3, 540p=5, 1080p=6, 4K=7.
When disabled, uses the manual pyr_level value.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

inference.py

@@ -5,8 +5,9 @@ from .bim_vfi_arch import BiMVFI
 class BiMVFIModel:
     """Clean inference wrapper around BiMVFI for ComfyUI integration."""
 
-    def __init__(self, checkpoint_path, pyr_level=3, device="cpu"):
+    def __init__(self, checkpoint_path, pyr_level=3, auto_pyr_level=True, device="cpu"):
         self.pyr_level = pyr_level
+        self.auto_pyr_level = auto_pyr_level
         self.device = device
 
         self.model = BiMVFI(pyr_level=pyr_level, feat_channels=32)
@@ -58,12 +59,25 @@ class BiMVFIModel:
         img0 = frame0.to(device)
         img1 = frame1.to(device)
 
+        if self.auto_pyr_level:
+            _, _, h, _ = img0.shape
+            if h >= 2160:
+                pyr_level = 7
+            elif h >= 1080:
+                pyr_level = 6
+            elif h >= 540:
+                pyr_level = 5
+            else:
+                pyr_level = 3
+        else:
+            pyr_level = self.pyr_level
+
         time_step_tensor = torch.tensor([time_step], device=device).view(1, 1, 1, 1)
 
         result_dict = self.model(
             img0=img0, img1=img1,
             time_step=time_step_tensor,
-            pyr_level=self.pyr_level,
+            pyr_level=pyr_level,
         )
 
         interp = result_dict["imgt_pred"]