<h1 align="center">WhisperX</h1>

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<img width="1216" align="center" alt="whisperx-arch" src="https://raw.githubusercontent.com/m-bain/whisperX/refs/heads/main/figures/pipeline.png">

<!-- <p align="left">Whisper-Based Automatic Speech Recognition (ASR) with improved timestamp accuracy + quality via forced phoneme alignment and voice-activity based batching for fast inference.</p> -->

<!-- <h2 align="left", id="what-is-it">What is it 🔎</h2> -->

This repository provides fast automatic speech recognition (70x realtime with large-v2) with word-level timestamps and speaker diarization.

- ⚡️ Batched inference for 70x realtime transcription using whisper large-v2
- 🪶 [faster-whisper](https://github.com/guillaumekln/faster-whisper) backend, requires <8GB gpu memory for large-v2 with beam_size=5
- 🎯 Accurate word-level timestamps using wav2vec2 alignment
- 👯‍♂️ Multispeaker ASR using speaker diarization from [pyannote-audio](https://github.com/pyannote/pyannote-audio) (speaker ID labels)
- 🗣️ VAD preprocessing, reduces hallucination & batching with no WER degradation

**Whisper** is an ASR model [developed by OpenAI](https://github.com/openai/whisper), trained on a large dataset of diverse audio. Whilst it does produces highly accurate transcriptions, the corresponding timestamps are at the utterance-level, not per word, and can be inaccurate by several seconds. OpenAI's whisper does not natively support batching.

**Phoneme-Based ASR** A suite of models finetuned to recognise the smallest unit of speech distinguishing one word from another, e.g. the element p in "tap". A popular example model is [wav2vec2.0](https://huggingface.co/facebook/wav2vec2-large-960h-lv60-self).

**Forced Alignment** refers to the process by which orthographic transcriptions are aligned to audio recordings to automatically generate phone level segmentation.

**Voice Activity Detection (VAD)** is the detection of the presence or absence of human speech.

**Speaker Diarization** is the process of partitioning an audio stream containing human speech into homogeneous segments according to the identity of each speaker.

<h2 align="left", id="highlights">New🚨</h2>

- 1st place at [Ego4d transcription challenge](https://eval.ai/web/challenges/challenge-page/1637/leaderboard/3931/WER) 🏆
- _WhisperX_ accepted at INTERSPEECH 2023
- v3 transcript segment-per-sentence: using nltk sent_tokenize for better subtitlting & better diarization
- v3 released, 70x speed-up open-sourced. Using batched whisper with [faster-whisper](https://github.com/guillaumekln/faster-whisper) backend!
- v2 released, code cleanup, imports whisper library VAD filtering is now turned on by default, as in the paper.
- Paper drop🎓👨‍🏫! Please see our [ArxiV preprint](https://arxiv.org/abs/2303.00747) for benchmarking and details of WhisperX. We also introduce more efficient batch inference resulting in large-v2 with \*60-70x REAL TIME speed.

<h2 align="left" id="setup">Setup ⚙️</h2>

### 1. Simple Installation (Recommended)

The easiest way to install WhisperX is through PyPi:

```bash
pip install whisperx
```

Or if using [uvx](https://docs.astral.sh/uv/guides/tools/#running-tools):

```bash
uvx whisperx
```

### 2. Advanced Installation Options

These installation methods are for developers or users with specific needs. If you're not sure, stick with the simple installation above.

#### Option A: Install from GitHub

To install directly from the GitHub repository:

```bash
uvx git+https://github.com/m-bain/whisperX.git
```

#### Option B: Developer Installation

If you want to modify the code or contribute to the project:

```bash
git clone https://github.com/m-bain/whisperX.git
cd whisperX
uv sync --all-extras --dev
```

> **Note**: The development version may contain experimental features and bugs. Use the stable PyPI release for production environments.

You may also need to install ffmpeg, rust etc. Follow openAI instructions here https://github.com/openai/whisper#setup.

### Common Issues & Troubleshooting 🔧

#### libcudnn Dependencies (GPU Users)

If you're using WhisperX with GPU support and encounter errors like:

- `Could not load library libcudnn_ops_infer.so.8`
- `Unable to load any of {libcudnn_cnn.so.9.1.0, libcudnn_cnn.so.9.1, libcudnn_cnn.so.9, libcudnn_cnn.so}`
- `libcudnn_ops_infer.so.8: cannot open shared object file: No such file or directory`

This means your system is missing the CUDA Deep Neural Network library (cuDNN). This library is needed for GPU acceleration but isn't always installed by default.

**Install cuDNN (example for apt based systems):**

```bash
sudo apt update
sudo apt install libcudnn8 libcudnn8-dev -y
```

### Speaker Diarization

To **enable Speaker Diarization**, include your Hugging Face access token (read) that you can generate from [Here](https://huggingface.co/settings/tokens) after the `--hf_token` argument and accept the user agreement for the following models: [Segmentation](https://huggingface.co/pyannote/segmentation-3.0) and [Speaker-Diarization-3.1](https://huggingface.co/pyannote/speaker-diarization-3.1) (if you choose to use Speaker-Diarization 2.x, follow requirements [here](https://huggingface.co/pyannote/speaker-diarization) instead.)

> **Note**<br>
> As of Oct 11, 2023, there is a known issue regarding slow performance with pyannote/Speaker-Diarization-3.0 in whisperX. It is due to dependency conflicts between faster-whisper and pyannote-audio 3.0.0. Please see [this issue](https://github.com/m-bain/whisperX/issues/499) for more details and potential workarounds.

<h2 align="left" id="example">Usage 💬 (command line)</h2>

### English

Run whisper on example segment (using default params, whisper small) add `--highlight_words True` to visualise word timings in the .srt file.

    whisperx path/to/audio.wav

Result using _WhisperX_ with forced alignment to wav2vec2.0 large:

https://user-images.githubusercontent.com/36994049/208253969-7e35fe2a-7541-434a-ae91-8e919540555d.mp4

Compare this to original whisper out the box, where many transcriptions are out of sync:

https://user-images.githubusercontent.com/36994049/207743923-b4f0d537-29ae-4be2-b404-bb941db73652.mov

For increased timestamp accuracy, at the cost of higher gpu mem, use bigger models (bigger alignment model not found to be that helpful, see paper) e.g.

    whisperx path/to/audio.wav --model large-v2 --align_model WAV2VEC2_ASR_LARGE_LV60K_960H --batch_size 4

To label the transcript with speaker ID's (set number of speakers if known e.g. `--min_speakers 2` `--max_speakers 2`):

    whisperx path/to/audio.wav --model large-v2 --diarize --highlight_words True

To run on CPU instead of GPU (and for running on Mac OS X):

    whisperx path/to/audio.wav --compute_type int8

### Other languages

The phoneme ASR alignment model is _language-specific_, for tested languages these models are [automatically picked from torchaudio pipelines or huggingface](https://github.com/m-bain/whisperX/blob/f2da2f858e99e4211fe4f64b5f2938b007827e17/whisperx/alignment.py#L24-L58).
Just pass in the `--language` code, and use the whisper `--model large`.

Currently default models provided for `{en, fr, de, es, it}` via torchaudio pipelines and many other languages via Hugging Face. Please find the list of currently supported languages under `DEFAULT_ALIGN_MODELS_HF` on [alignment.py](https://github.com/m-bain/whisperX/blob/main/whisperx/alignment.py). If the detected language is not in this list, you need to find a phoneme-based ASR model from [huggingface model hub](https://huggingface.co/models) and test it on your data.

#### E.g. German

    whisperx --model large-v2 --language de path/to/audio.wav

https://user-images.githubusercontent.com/36994049/208298811-e36002ba-3698-4731-97d4-0aebd07e0eb3.mov

See more examples in other languages [here](EXAMPLES.md).

## Python usage 🐍

```python
import whisperx
import gc

device = "cuda"
audio_file = "audio.mp3"
batch_size = 16 # reduce if low on GPU mem
compute_type = "float16" # change to "int8" if low on GPU mem (may reduce accuracy)

# 1. Transcribe with original whisper (batched)
model = whisperx.load_model("large-v2", device, compute_type=compute_type)

# save model to local path (optional)
# model_dir = "/path/"
# model = whisperx.load_model("large-v2", device, compute_type=compute_type, download_root=model_dir)

audio = whisperx.load_audio(audio_file)
result = model.transcribe(audio, batch_size=batch_size)
print(result["segments"]) # before alignment

# delete model if low on GPU resources
# import gc; import torch; gc.collect(); torch.cuda.empty_cache(); del model

# 2. Align whisper output
model_a, metadata = whisperx.load_align_model(language_code=result["language"], device=device)
result = whisperx.align(result["segments"], model_a, metadata, audio, device, return_char_alignments=False)

print(result["segments"]) # after alignment

# delete model if low on GPU resources
# import gc; import torch; gc.collect(); torch.cuda.empty_cache(); del model_a

# 3. Assign speaker labels
diarize_model = whisperx.diarize.DiarizationPipeline(use_auth_token=YOUR_HF_TOKEN, device=device)

# add min/max number of speakers if known
diarize_segments = diarize_model(audio)
# diarize_model(audio, min_speakers=min_speakers, max_speakers=max_speakers)

result = whisperx.assign_word_speakers(diarize_segments, result)
print(diarize_segments)
print(result["segments"]) # segments are now assigned speaker IDs
```

## Demos 🚀

[![Replicate (large-v3](https://img.shields.io/static/v1?label=Replicate+WhisperX+large-v3&message=Demo+%26+Cloud+API&color=blue)](https://replicate.com/victor-upmeet/whisperx)
[![Replicate (large-v2](https://img.shields.io/static/v1?label=Replicate+WhisperX+large-v2&message=Demo+%26+Cloud+API&color=blue)](https://replicate.com/daanelson/whisperx)
[![Replicate (medium)](https://img.shields.io/static/v1?label=Replicate+WhisperX+medium&message=Demo+%26+Cloud+API&color=blue)](https://replicate.com/carnifexer/whisperx)

If you don't have access to your own GPUs, use the links above to try out WhisperX.

<h2 align="left" id="whisper-mod">Technical Details 👷‍♂️</h2>

For specific details on the batching and alignment, the effect of VAD, as well as the chosen alignment model, see the preprint [paper](https://www.robots.ox.ac.uk/~vgg/publications/2023/Bain23/bain23.pdf).

To reduce GPU memory requirements, try any of the following (2. & 3. can affect quality):

1.  reduce batch size, e.g. `--batch_size 4`
2.  use a smaller ASR model `--model base`
3.  Use lighter compute type `--compute_type int8`

Transcription differences from openai's whisper:

1. Transcription without timestamps. To enable single pass batching, whisper inference is performed `--without_timestamps True`, this ensures 1 forward pass per sample in the batch. However, this can cause discrepancies the default whisper output.
2. VAD-based segment transcription, unlike the buffered transcription of openai's. In the WhisperX paper we show this reduces WER, and enables accurate batched inference
3. `--condition_on_prev_text` is set to `False` by default (reduces hallucination)

<h2 align="left" id="limitations">Limitations ⚠️</h2>

- Transcript words which do not contain characters in the alignment models dictionary e.g. "2014." or "£13.60" cannot be aligned and therefore are not given a timing.
- Overlapping speech is not handled particularly well by whisper nor whisperx
- Diarization is far from perfect
- Language specific wav2vec2 model is needed

<h2 align="left" id="contribute">Contribute 🧑‍🏫</h2>

If you are multilingual, a major way you can contribute to this project is to find phoneme models on huggingface (or train your own) and test them on speech for the target language. If the results look good send a pull request and some examples showing its success.

Bug finding and pull requests are also highly appreciated to keep this project going, since it's already diverging from the original research scope.

<h2 align="left" id="coming-soon">TODO 🗓</h2>

- [x] Multilingual init

- [x] Automatic align model selection based on language detection

- [x] Python usage

- [x] Incorporating speaker diarization

- [x] Model flush, for low gpu mem resources

- [x] Faster-whisper backend

- [x] Add max-line etc. see (openai's whisper utils.py)

- [x] Sentence-level segments (nltk toolbox)

- [x] Improve alignment logic

- [ ] update examples with diarization and word highlighting

- [ ] Subtitle .ass output <- bring this back (removed in v3)

- [ ] Add benchmarking code (TEDLIUM for spd/WER & word segmentation)

- [x] Allow silero-vad as alternative VAD option

- [ ] Improve diarization (word level). _Harder than first thought..._

<h2 align="left" id="contact">Contact/Support 📇</h2>

Contact maxhbain@gmail.com for queries.

<a href="https://www.buymeacoffee.com/maxhbain" target="_blank"><img src="https://cdn.buymeacoffee.com/buttons/default-orange.png" alt="Buy Me A Coffee" height="41" width="174"></a>

<h2 align="left" id="acks">Acknowledgements 🙏</h2>

This work, and my PhD, is supported by the [VGG (Visual Geometry Group)](https://www.robots.ox.ac.uk/~vgg/) and the University of Oxford.

Of course, this is builds on [openAI's whisper](https://github.com/openai/whisper).
Borrows important alignment code from [PyTorch tutorial on forced alignment](https://pytorch.org/tutorials/intermediate/forced_alignment_with_torchaudio_tutorial.html)
And uses the wonderful pyannote VAD / Diarization https://github.com/pyannote/pyannote-audio

Valuable VAD & Diarization Models from:

- [pyannote audio][https://github.com/pyannote/pyannote-audio]
- [silero vad][https://github.com/snakers4/silero-vad]

Great backend from [faster-whisper](https://github.com/guillaumekln/faster-whisper) and [CTranslate2](https://github.com/OpenNMT/CTranslate2)

Those who have [supported this work financially](https://www.buymeacoffee.com/maxhbain) 🙏

Finally, thanks to the OS [contributors](https://github.com/m-bain/whisperX/graphs/contributors) of this project, keeping it going and identifying bugs.

<h2 align="left" id="cite">Citation</h2>
If you use this in your research, please cite the paper:

```bibtex
@article{bain2022whisperx,
  title={WhisperX: Time-Accurate Speech Transcription of Long-Form Audio},
  author={Bain, Max and Huh, Jaesung and Han, Tengda and Zisserman, Andrew},
  journal={INTERSPEECH 2023},
  year={2023}
}
```
