# Squeezeformer:  An Efficient Transformer for Automatic Speech Recognition
![teaser](https://user-images.githubusercontent.com/50283958/172300924-157b8458-0e95-4b2e-b992-fc7927738146.png)


We provide testing codes for Squeezeformer, along with the pre-trained checkpoints.

Check out our [paper](https://arxiv.org/pdf/2206.00888.pdf) for more details.


Squeezeformer is now supported at NVIDIA's  [NeMo](https://docs.nvidia.com/deeplearning/nemo/user-guide/docs/en/stable/starthere/intro.html#:~:text=NVIDIA%20NeMo%2C%20part%20of%20the,%2DSpeech%20(TTS)%20models.) library as well, along with the training recipes and scripts. Please check out [link](https://github.com/NVIDIA/NeMo/tree/main/examples/asr/conf/squeezeformer).


## Install Squeezeformer

We recommend using Python version 3.8.  

### 1. Install dependancies

We support Tensorflow version of 2.5. Run the following commands depending on your target device type.

* Running on CPUs: `pip install -e '.[tf2.5]'`
* Running on GPUs: `pip install -e '.[tf2.5-gpu]'`

### 2. Install CTC decoder 
```bash
cd scripts
bash install_ctc_decoders.sh
```

## Prepare Dataset

### 1. Download Librispeech

[Librispeech](https://ieeexplore.ieee.org/document/7178964) is a widely-used ASR benchmark that consists of 960hr speech corpus with text transcriptions.
The dataset consists of 3 training sets (`train-clean-100`, `train-clean-360`, `train-other-500`), 
2 development sets (`dev-clean`, `dev-other`), and 2 test sets (`test-clean`, `test-other`).

Download the datasets from this [link](http://www.openslr.org/12) and untar them.
If this is for testing purposes only, you can skip the training datasets to save disk space.
You should have flac files under `{dataset_path}/LibriSpeech`.

### 2. Create Manifest Files

Once you download the datasets, you should create a manifest file that links the file path to the audio input and its transcription.
We use a script from [TensorFlowASR](https://github.com/TensorSpeech/TensorFlowASR).

```bash
cd scripts
python create_librispeech_trans_all.py --data {dataset_path}/LibriSpeech --output {tsv_dir}
```
* The `dataset_path` is the directory that you untarred the datasets in the previous step.
* This script creates tsv files under `tsv_dir` that list the audio file path, duration, and the transcription.
* To skip processing the training datasets, use an additional argument `--mode test-only`.

If you have followed the instruction correctly, you should have the following files under `tsv_dir`.
* `dev_clean.tsv`, `dev_other.tsv`, `test_clean.tsv`, `test_other.tsv`
* `train_clean_100.tsv`, `train_clean_360.tsv`, `train_other_500.tsv` (if not `--mode test-only`)
* `train_other.tsv` that merges all training tsv files into one (if not `--mode test-only`)


## Testing Squeezeformer

### 1. Download Pre-trained Checkpoints

We provide pre-trained checkpoints for all variants of Squeezeformer.

|      **Model**      |                                                  **Checkpoint**                            | **test-clean** | **test-other** |
| :-----------------: | :---------------------------------------------------------------------------------------:  | :------------: | :------------: |
|  Squeezeformer-XS   | [link](https://drive.google.com/file/d/1qSukKHz2ltBiWU-xHGmI-P9ziPJcLcSu/view?usp=sharing) |    3.74        |      9.09      |
|  Squeezeformer-S    | [link](https://drive.google.com/file/d/1PGao0AOe5aQXc-9eh2RDQZnZ4UcefcHB/view?usp=sharing) |    3.08        |      7.47      |
|  Squeezeformer-SM   | [link](https://drive.google.com/file/d/17cL1p0KJgT-EBu_-bg3bF7-Uh-pnf-8k/view?usp=sharing) |    2.79        |      6.89      |
|  Squeezeformer-M    | [link](https://drive.google.com/file/d/1fbaby-nOxHAGH0GqLoA0DIjFDPaOBl1d/view?usp=sharing) |    2.56        |      6.50      |
|  Squeezeformer-ML   | [link](https://drive.google.com/file/d/1-ZPtJjJUHrcbhPp03KioadenBtKpp-km/view?usp=sharing) |    2.61        |      6.05      |
|  Squeezeformer-L    | [link](https://drive.google.com/file/d/1LJua7A4ZMoZFi2cirf9AnYEl51pmC-m5/view?usp=sharing) |    2.47        |      5.97      |


### 2. Run Inference!

Run the following commands:
```bash
cd examples/squeezeformer
python test.py --bs {batch_size} --config configs/squeezeformer-S.yml --saved squeezeformer-S.h5 \
    --dataset_path {tsv_dir} --dataset {dev_clean|dev_other|test_clean|test_other}
```

* `tsv_dir` is the directory path to the tsv manifest files that you created in the previous step.
* You can test on other Squeezeformer models by changing `--config` and `--saved`, e.g., Squeezeformer-L or Squeezeformer-M.

## External implementations 
We are thankful to all the researchers who have extended Squeezeformer for different purposes.

|      **Description**      | **Checkpoint**                                    | 
| :-----------------------: | :----------------------------------------------:  |
|  PyTorch implementation   | [link](https://github.com/upskyy/Squeezeformer)   | 
|  NeMo                     | [link](https://github.com/NVIDIA/NeMo/tree/main/examples/asr/conf/squeezeformer)   | 


## Citation
Squeezeformer has been developed as part of the following paper. We appreciate it if you would please cite the following paper if you found the library useful for your work:

```text
@article{kim2022squeezeformer,
  title={Squeezeformer: An Efficient Transformer for Automatic Speech Recognition},
  author={Kim, Sehoon and Gholami, Amir and Shaw, Albert and Lee, Nicholas and Mangalam, Karttikeya and Malik, Jitendra and Mahoney, Michael W and Keutzer, Kurt},
  journal={arxiv:2206.00888},
  year={2022}
}
```