Improve error handling and logging for AudioMediaIO compatibility

- Add warnings to inform users which compatibility mode is being used
- Handle both AttributeError and ImportError for better coverage
- Add __init__ method to inherited class for consistency
- Provide clear diagnostic messages when patching fails

Co-authored-by: donglixp <1070872+donglixp@users.noreply.github.com>

vllm_plugin/model.py

@@ -73,11 +73,21 @@ def _ffmpeg_load_file(filepath) -> tuple[np.ndarray, int]:
 
 # Register FFmpeg-based audio loader
 import vllm.multimodal.audio as _vllm_audio_module
+import warnings
+
+# Handle both old and new vLLM versions
+# In newer versions, AudioMediaIO may not exist or may have been moved
+try:
     _OriginalAudioMediaIO = _vllm_audio_module.AudioMediaIO
     
     class _PatchedAudioMediaIO(_OriginalAudioMediaIO):
         """AudioMediaIO implementation using FFmpeg for audio decoding."""
         
+        def __init__(self, **kwargs):
+            # Call parent constructor if it exists
+            if hasattr(super(), '__init__'):
+                super().__init__(**kwargs)
+        
         def load_bytes(self, data: bytes) -> tuple[np.ndarray, int]:
             return _ffmpeg_load_bytes(data, media_type=None)
         
@@ -91,8 +101,48 @@ class _PatchedAudioMediaIO(_OriginalAudioMediaIO):
     _vllm_audio_module.AudioMediaIO = _PatchedAudioMediaIO
     
     # Also patch in utils module where it's imported
+    try:
         import vllm.multimodal.utils as _vllm_utils_module
         _vllm_utils_module.AudioMediaIO = _PatchedAudioMediaIO
+    except (ImportError, AttributeError) as e:
+        warnings.warn(f"Could not patch AudioMediaIO in vllm.multimodal.utils: {e}", UserWarning)
+        
+except (AttributeError, ImportError) as e:
+    # AudioMediaIO doesn't exist in this vLLM version
+    # Define our own standalone implementation
+    warnings.warn(
+        f"AudioMediaIO not found in vllm.multimodal.audio ({e}). "
+        "Using standalone FFmpeg-based implementation for compatibility.",
+        UserWarning
+    )
+    
+    class _PatchedAudioMediaIO:
+        """Standalone AudioMediaIO implementation using FFmpeg for audio decoding.
+        
+        This is used when vLLM doesn't provide AudioMediaIO or it's been moved/removed.
+        """
+        
+        def __init__(self, **kwargs):
+            pass
+        
+        def load_bytes(self, data: bytes) -> tuple[np.ndarray, int]:
+            return _ffmpeg_load_bytes(data, media_type=None)
+        
+        def load_base64(self, media_type: str, data: str) -> tuple[np.ndarray, int]:
+            return _ffmpeg_load_bytes(base64.b64decode(data), media_type=media_type)
+        
+        def load_file(self, filepath) -> tuple[np.ndarray, int]:
+            return _ffmpeg_load_file(filepath)
+    
+    # Try to register it in the module if possible
+    try:
+        _vllm_audio_module.AudioMediaIO = _PatchedAudioMediaIO
+    except (AttributeError, TypeError) as e:
+        warnings.warn(
+            f"Could not register AudioMediaIO in vllm.multimodal.audio: {e}. "
+            "Audio loading will use FFmpeg functions directly.",
+            UserWarning
+        )
 
 # ============================================================================