[Bugfix] Make `kaldi_native_fbank` optional (#35996)

Signed-off-by: DarkLight1337 <tlleungac@connect.ust.hk>

requirements/common.txt

@@ -57,4 +57,3 @@ opentelemetry-sdk >= 1.27.0
 opentelemetry-api >= 1.27.0
 opentelemetry-exporter-otlp >= 1.27.0
 opentelemetry-semantic-conventions-ai >= 0.4.1
-kaldi-native-fbank >= 1.18.7

requirements/test.in

@@ -67,6 +67,7 @@ segmentation-models-pytorch > 0.4.0 # Required for Prithvi tests
 gpt-oss >= 0.0.7; python_version > '3.11'
 
 perceptron # required for isaac test
+kaldi-native-fbank >= 1.18.7 # required for fireredasr2 test
 
 # Newer versions of datasets require torchcoded, that makes the tests fail in CI because of a missing library.
 # Older versions are in conflict with teerratorch requirements.

requirements/test.txt

@@ -417,6 +417,8 @@ jsonschema-specifications==2024.10.1
     # via jsonschema
 junit-xml==1.9
     # via schemathesis
+kaldi-native-fbank==1.22.3
+    # via -r requirements/test.in
 kaleido==0.2.1
     # via genai-perf
 kiwisolver==1.4.7

vllm/transformers_utils/processors/fireredasr2_processor.py

 # SPDX-License-Identifier: Apache-2.0
 # SPDX-FileCopyrightText: Copyright contributors to the vLLM project
 
+from typing import TYPE_CHECKING
 
-import kaldi_native_fbank as knf
 import numpy as np
 import torch
 import torch.nn.functional as F
@@ -16,6 +16,13 @@ from transformers.processing_utils import ProcessorMixin
 from transformers.utils import TensorType
 
 from vllm.logger import init_logger
+from vllm.utils.import_utils import LazyLoader
+
+if TYPE_CHECKING:
+    import kaldi_native_fbank as knf
+else:
+    knf = LazyLoader("knf", globals(), "kaldi_native_fbank")
+
 
 logger = init_logger(__name__)