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Fixed an issue where `detect_language` crashed when `vad_parameters` was in dictionary format

https://github.com/SYSTRAN/faster-whisper/pull/1662

Purpose​

According to the documentation and type hints, WhisperModel.detect_language accepts vad_parameters as a "Silero VAD parameter dict or VadOptions." This is the same convention as transcribe. However, the logic that converts a dict to VadOptions is only present in transcribe and is missing from detect_language, so passing a dict as described in the documentation causes a crash.

model.detect_language(audio, vad_filter=True, vad_parameters=dict(min_silence_duration_ms=500))
# AttributeError: 'dict' object has no attribute 'threshold'

Passing an VadOptions object or None works as expected; only the dict format specified in the documentation fails.

Changes​

  • faster_whisper/transcribe.py — In detect_language, convert dict to VadOptions. Same as the method already used by transcribe (+2)
  • tests/test_transcribe.py — Added test_detect_language_vad_parameters_dict (+12)

Tests​

$ pytest tests/test_transcribe.py::test_detect_language_vad_parameters_dict   # Before modification: Failed with an AttributeError
$ pytest tests/test_transcribe.py::test_detect_language_vad_parameters_dict   # After modification: 1 passed
$ black --check ...   # No changes
$ flake8 ... # Passed

Tested on the tiny model, CPU, and Python 3.12. All tests (20 cases) were confirmed to pass during the investigation phase.

Duplicate Check​

I searched for detect_language + vad_parameters, as well as open and closed issues and PRs with error messages, and found no duplicate reports. #1150 (Type hint cleanup) modifies the surrounding lines of the same block but does not include the conversion logic.

Results​

Submitted to the master branch on October 6, 2026. Awaiting review. The scope of the changes is 2 files, +14.

2026-10-07 Update: The maintainer (Purfview) closed this PR on 2026-10-06 without explanation. It was not merged. Issue #1661, posted on the same day, was closed with the comment “AI bot problems.” Since this repository does not accept contributions from AI assistants, I will not submit any further changes.