fix(audio): derive transcription filename with os.path.basename

process_audio_file derived the multipart filename from a PathLike input
with file_path.split("/")[-1]. On Windows, str(Path('C:/dir/name.mp3'))
is 'C:\\dir\\name.mp3', which contains no forward slash, so the split
returned the entire path (drive letter and backslashes) instead of the
basename. That full path was then sent to provider transcription APIs as
the form-data file name.

Use os.path.basename, matching the sibling PathLike file-input sink in
ocr/main.py. Add a regression test that patches os.path to ntpath to
reproduce Windows semantics on any host.

Signed-off-by: Anas Khan <83116240+anxkhn@users.noreply.github.com>

litellm/litellm_core_utils/audio_utils/utils.py

@@ -69,7 +69,7 @@ def process_audio_file(audio_file: FileTypes) -> ProcessedAudioFile:
         file_path = str(audio_file)
         with open(file_path, "rb") as f:
             file_content = f.read()
-        filename = file_path.split("/")[-1]
+        filename = os.path.basename(file_path)
     elif isinstance(audio_file, tuple):
         # Tuple format: (filename, content, content_type) or (filename, content)
         if len(audio_file) >= 2:

tests/test_litellm/litellm_core_utils/test_audio_utils.py

@@ -69,6 +69,35 @@ class TestProcessAudioFile:
         with pytest.raises(ValueError, match="does not accept bare str inputs"):
             process_audio_file("/etc/passwd")
 
+    def test_process_windows_pathlib_input_basename(self):
+        """A Windows path must yield only the basename, not the full drive path.
+
+        On Windows, str(Path('C:/dir/name.mp3')) is 'C:\\dir\\name.mp3', which
+        contains no '/'. Deriving the filename with str.split('/')[-1] would send
+        the entire path (drive letter and backslashes) to the provider as the
+        multipart file name. os.path is patched to ntpath here to reproduce
+        Windows semantics on any host.
+        """
+        import ntpath
+        from pathlib import PureWindowsPath
+
+        windows_path = PureWindowsPath("C:/Users/me/audio recording.mp3")
+        test_content = b"test audio content"
+
+        with (
+            patch("litellm.litellm_core_utils.audio_utils.utils.os.path", ntpath),
+            patch(
+                "litellm.litellm_core_utils.audio_utils.utils.open",
+                mock_open(read_data=test_content),
+                create=True,
+            ),
+        ):
+            result = process_audio_file(windows_path)
+
+        assert result.file_content == test_content
+        assert result.filename == "audio recording.mp3"
+        assert result.content_type == "audio/mpeg"
+
     def test_process_tuple_input_with_bytes(self):
         """Test processing tuple input with bytes content"""
         filename = "test.wav"