faster-whisper
Whisper speech recognition rebuilt on CTranslate2 for quicker, lower-memory transcription on CPU or GPU.
About
SYSTRAN maintains faster-whisper, which runs OpenAI's Whisper speech recognition models on CTranslate2, a C++ Transformer inference engine, in place of PyTorch. The payoff is speed and memory: the project's own benchmark transcribes 13 minutes of audio with large-v2 on an RTX 3070 Ti in about a minute at FP16, and in roughly 16 seconds with batched INT8 inference. You load a model by size name, from tiny through large-v3 and turbo plus distil-whisper checkpoints, and converted weights download from Hugging Face automatically; CTranslate2's converter handles your own fine-tuned Transformers checkpoints. Transcription yields timestamped segments lazily, with language detection, optional word timings, and a Silero voice activity filter that drops silence. PyAV handles decoding, so no system FFmpeg is required. It needs Python 3.9 or newer; CPU works, and GPU runs need NVIDIA's CUDA 12 cuBLAS and cuDNN 9 libraries. The code is MIT, as are the original Whisper weights, so commercial products can embed it. WhisperX, WhisperLive, and the speaches server build on it. It fits developers adding offline transcription to apps or pipelines.
Should you use faster-whisper?
Pick it when
Pick faster-whisper when you want Whisper-level accuracy from Python with less memory and much less time per file, for batch transcription on CPU servers or modest GPUs, with 8-bit quantization and no separate FFmpeg install.
Look elsewhere when
Skip it if you need forced-alignment word timing or speaker labels, which WhisperX layers on top, or if you must ship inside a mobile or desktop app without a Python runtime, where whisper.cpp is the standard route.
Alternatives to faster-whisper
- WhisperX
Adds forced-alignment word timestamps and diarization on top of Whisper, at the cost of extra models, more setup, and a BSD-4-Clause license.
- Whisper.cpp
C/C++ with no Python runtime, runs on phones, Raspberry Pi, and WebAssembly, but calling it from a Python service is less direct.
- Distil-Whisper
About six times faster and half the size of Whisper but English only, while faster-whisper keeps every Whisper language.
- Insanely Fast Whisper
Batched Flash Attention CLI for CUDA or Apple Silicon GPUs with Pyannote diarization built in, but it needs about 6 GB of VRAM where faster-whisper also runs well on CPU.
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Details
- Category
- Audio & Speech
- Price
- Free
- Platform
- Local/Desktop
- Difficulty
- Easy (2/5)
- License
- MIT
- Added
- Jan 29, 2026
Tags
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