Add 404 fallback to deferred I2V model loading

- Apply same 404 fallback strategy to deferred I2V model loading
- Try DiffusionPipeline as fallback when model_index.json not found
- Ensures all model loading paths have consistent error handling

videogen

@@ -7226,8 +7226,31 @@ def main(args):
             # Reload the I2V pipeline
             try:
                 pipe = PipelineClass.from_pretrained(model_id_to_load, **pipe_kwargs)
+            except Exception as e:
+                error_str = str(e)
+                
+                # Check if this is a 404 error for model_index.json
+                is_404_error = "404" in error_str or "Entry Not Found" in error_str or "not found" in error_str.lower()
                 
-                # Apply LoRA if this is a LoRA model
+                if is_404_error and "model_index.json" in error_str:
+                    print(f"\n⚠️  I2V model model_index.json not found at root level")
+                    print(f"   Attempting alternative loading strategies...")
+                    
+                    # Try with DiffusionPipeline (generic loader)
+                    try:
+                        print(f"   Trying generic DiffusionPipeline for I2V model...")
+                        from diffusers import DiffusionPipeline
+                        pipe = DiffusionPipeline.from_pretrained(model_id_to_load, **pipe_kwargs)
+                        print(f"  ✅ Successfully loaded I2V model with DiffusionPipeline")
+                        PipelineClass = DiffusionPipeline
+                    except Exception as generic_e:
+                        if debug:
+                            print(f"   [DEBUG] Generic loader also failed: {generic_e}")
+                        raise e  # Re-raise if fallback failed
+                else:
+                    raise e  # Re-raise for non-404 errors
+            
+            # Apply LoRA if this is a LoRA model
                 if is_lora and lora_id:
                     print(f"  Loading LoRA adapter: {lora_id}")
                     try: