# Speech2Text
## Overview
The Speech2Text model was proposed in [fairseq S2T: Fast Speech-to-Text Modeling with fairseq](https://arxiv.org/abs/2010.05171) by Changhan Wang, Yun Tang, Xutai Ma, Anne Wu, Dmytro Okhonko, Juan Pino. It's a
transformer-based seq2seq (encoder-decoder) model designed for end-to-end Automatic Speech Recognition (ASR) and Speech
Translation (ST). It uses a convolutional downsampler to reduce the length of speech inputs by 3/4th before they are
fed into the encoder. The model is trained with standard autoregressive cross-entropy loss and generates the
transcripts/translations autoregressively. Speech2Text has been fine-tuned on several datasets for ASR and ST:
[LibriSpeech](http://www.openslr.org/12), [CoVoST 2](https://github.com/facebookresearch/covost), [MuST-C](https://ict.fbk.eu/must-c/).
This model was contributed by [valhalla](https://huggingface.co/valhalla). The original code can be found [here](https://github.com/pytorch/fairseq/tree/master/examples/speech_to_text).
## Inference
Speech2Text is a speech model that accepts a float tensor of log-mel filter-bank features extracted from the speech
signal. It's a transformer-based seq2seq model, so the transcripts/translations are generated autoregressively. The
`generate()` method can be used for inference.
The [`Speech2TextFeatureExtractor`] class is responsible for extracting the log-mel filter-bank
features. The [`Speech2TextProcessor`] wraps [`Speech2TextFeatureExtractor`] and
[`Speech2TextTokenizer`] into a single instance to both extract the input features and decode the
predicted token ids.
The feature extractor depends on `torchaudio` and the tokenizer depends on `sentencepiece` so be sure to
install those packages before running the examples. You could either install those as extra speech dependencies with
`pip install transformers"[speech, sentencepiece]"` or install the packages separately with `pip install torchaudio sentencepiece`. Also `torchaudio` requires the development version of the [libsndfile](http://www.mega-nerd.com/libsndfile/) package which can be installed via a system package manager. On Ubuntu it can
be installed as follows: `apt install libsndfile1-dev`
- ASR and Speech Translation
```python
>>> import torch
>>> from transformers import Speech2TextProcessor, Speech2TextForConditionalGeneration
>>> from datasets import load_dataset
>>> model = Speech2TextForConditionalGeneration.from_pretrained("facebook/s2t-small-librispeech-asr")
>>> processor = Speech2TextProcessor.from_pretrained("facebook/s2t-small-librispeech-asr")
>>> ds = load_dataset("hf-internal-testing/librispeech_asr_demo", "clean", split="validation")
>>> inputs = processor(ds[0]["audio"]["array"], sampling_rate=ds[0]["audio"]["sampling_rate"], return_tensors="pt")
>>> generated_ids = model.generate(inputs["input_features"], attention_mask=inputs["attention_mask"])
>>> transcription = processor.batch_decode(generated_ids, skip_special_tokens=True)
>>> transcription
['mister quilter is the apostle of the middle classes and we are glad to welcome his gospel']
```
- Multilingual speech translation
For multilingual speech translation models, `eos_token_id` is used as the `decoder_start_token_id` and
the target language id is forced as the first generated token. To force the target language id as the first
generated token, pass the `forced_bos_token_id` parameter to the `generate()` method. The following
example shows how to translate English speech to French text using the *facebook/s2t-medium-mustc-multilingual-st*
checkpoint.
```python
>>> import torch
>>> from transformers import Speech2TextProcessor, Speech2TextForConditionalGeneration
>>> from datasets import load_dataset
>>> model = Speech2TextForConditionalGeneration.from_pretrained("facebook/s2t-medium-mustc-multilingual-st")
>>> processor = Speech2TextProcessor.from_pretrained("facebook/s2t-medium-mustc-multilingual-st")
>>> ds = load_dataset("hf-internal-testing/librispeech_asr_demo", "clean", split="validation")
>>> inputs = processor(ds[0]["audio"]["array"], sampling_rate=ds[0]["audio"]["sampling_rate"], return_tensors="pt")
>>> generated_ids = model.generate(
... inputs["input_features"],
... attention_mask=inputs["attention_mask"],
... forced_bos_token_id=processor.tokenizer.lang_code_to_id["fr"],
... )
>>> translation = processor.batch_decode(generated_ids, skip_special_tokens=True)
>>> translation
["(Vidéo) Si M. Kilder est l'apossible des classes moyennes, et nous sommes heureux d'être accueillis dans son évangile."]
```
See the [model hub](https://huggingface.co/models?filter=speech_to_text) to look for Speech2Text checkpoints.
## Speech2TextConfig
[[autodoc]] Speech2TextConfig
## Speech2TextTokenizer
[[autodoc]] Speech2TextTokenizer
- build_inputs_with_special_tokens
- get_special_tokens_mask
- create_token_type_ids_from_sequences
- save_vocabulary
## Speech2TextFeatureExtractor
[[autodoc]] Speech2TextFeatureExtractor
- __call__
## Speech2TextProcessor
[[autodoc]] Speech2TextProcessor
- __call__
- from_pretrained
- save_pretrained
- batch_decode
- decode
## Speech2TextModel
[[autodoc]] Speech2TextModel
- forward
## Speech2TextForConditionalGeneration
[[autodoc]] Speech2TextForConditionalGeneration
- forward
## TFSpeech2TextModel
[[autodoc]] TFSpeech2TextModel
- call
## TFSpeech2TextForConditionalGeneration
[[autodoc]] TFSpeech2TextForConditionalGeneration
- call
