fix: handle ImportError in load_audio (#39473)

Signed-off-by: Yiyang Liu <37043548+ianliuy@users.noreply.github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

vllm/multimodal/media/audio.py

@@ -9,11 +9,14 @@ import numpy.typing as npt
 import pybase64
 import torch
 
+from vllm.logger import init_logger
 from vllm.utils.import_utils import PlaceholderModule
 from vllm.utils.serial_utils import tensor2base64
 
 from .base import MediaIO
 
+logger = init_logger(__name__)
+
 try:
     import av
 except ImportError:
@@ -139,6 +142,12 @@ def load_audio(
 ):
     try:
         return load_audio_soundfile(path, sr=sr, mono=mono)
+    except ImportError as exc:
+        # soundfile (or resampy) is not installed — fall through to pyav.
+        # NOTE: this clause must stay BEFORE ``soundfile.LibsndfileError``
+        # because when soundfile is a PlaceholderModule, evaluating
+        # ``soundfile.LibsndfileError`` itself raises ImportError.
+        logger.error("Failed to load audio via soundfile: %r", exc)
     except soundfile.LibsndfileError as exc:
         # Only fall back for known format-detection failures.
         # Re-raise anything else (e.g. corrupt but recognised format).
@@ -150,6 +159,8 @@ def load_audio(
         path.seek(0)
     try:
         return load_audio_pyav(path, sr=sr, mono=mono)
+    except ImportError:
+        raise  # Let PlaceholderModule's message ("install vllm[audio]") propagate.
     except Exception as pyav_exc:
         raise ValueError("Invalid or unsupported audio file.") from pyav_exc