# icefall

**Repository Path**: heyadax/icefall

## Basic Information

- **Project Name**: icefall
- **Description**: No description available
- **Primary Language**: Unknown
- **License**: Apache-2.0
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2025-11-18
- **Last Updated**: 2025-11-18

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

<div align="center">
<img src="https://raw.githubusercontent.com/k2-fsa/icefall/master/docs/source/_static/logo.png" width=168>
</div>

# Introduction

The icefall project contains speech-related recipes for various datasets
using [k2-fsa](https://github.com/k2-fsa/k2) and [lhotse](https://github.com/lhotse-speech/lhotse).

You can use [sherpa](https://github.com/k2-fsa/sherpa), [sherpa-ncnn](https://github.com/k2-fsa/sherpa-ncnn) or [sherpa-onnx](https://github.com/k2-fsa/sherpa-onnx) for deployment with models
in icefall; these frameworks also support models not included in icefall; please refer to respective documents for more details.

You can try pre-trained models from within your browser without the need
to download or install anything by visiting this [huggingface space](https://huggingface.co/spaces/k2-fsa/automatic-speech-recognition).
Please refer to [document](https://k2-fsa.github.io/icefall/huggingface/spaces.html) for more details.

# Installation

Please refer to [document](https://k2-fsa.github.io/icefall/installation/index.html)
for installation.

# Recipes

Please refer to [document](https://k2-fsa.github.io/icefall/recipes/index.html)
for more details.

## ASR: Automatic Speech Recognition

### Supported Datasets
  - [yesno][yesno]
  
  - [Aidatatang_200zh][aidatatang_200zh]
  - [Aishell][aishell]
  - [Aishell2][aishell2]
  - [Aishell4][aishell4]
  - [Alimeeting][alimeeting]
  - [AMI][ami]
  - [CommonVoice][commonvoice]
  - [Corpus of Spontaneous Japanese][csj]
  - [GigaSpeech][gigaspeech]
  - [LibriCSS][libricss]
  - [LibriSpeech][librispeech]
  - [Libriheavy][libriheavy]
  - [Multi-Dialect Broadcast News Arabic Speech Recognition][mgb2]
  - [SPGISpeech][spgispeech]
  - [Switchboard][swbd]
  - [TIMIT][timit]
  - [TED-LIUM3][tedlium3]
  - [TAL_CSASR][tal_csasr]
  - [Voxpopuli][voxpopuli]
  - [XBMU-AMDO31][xbmu-amdo31]
  - [WenetSpeech][wenetspeech]
  
More datasets will be added in the future.

### Supported Models

The [LibriSpeech][librispeech] recipe supports the most comprehensive set of models, you are welcome to try them out.

#### CTC 
  - TDNN LSTM CTC
  - Conformer CTC
  - Zipformer CTC

#### MMI
  - Conformer MMI
  - Zipformer MMI

#### Transducer
  - Conformer-based Encoder
  - LSTM-based Encoder
  - Zipformer-based Encoder
  - LSTM-based Predictor
  - [Stateless Predictor](https://research.google/pubs/rnn-transducer-with-stateless-prediction-network/)

#### Whisper
  - [OpenAi Whisper](https://arxiv.org/abs/2212.04356) (We support fine-tuning on AiShell-1.)

If you are willing to contribute to icefall, please refer to [contributing](https://k2-fsa.github.io/icefall/contributing/index.html) for more details.

We would like to highlight the performance of some of the recipes here.

### [yesno][yesno]

This is the simplest ASR recipe in `icefall` and can be run on CPU.
Training takes less than 30 seconds and gives you the following WER:

```
[test_set] %WER 0.42% [1 / 240, 0 ins, 1 del, 0 sub ]
```
We provide a Colab notebook for this recipe: [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/drive/1tIjjzaJc3IvGyKiMCDWO-TSnBgkcuN3B?usp=sharing)


### [LibriSpeech][librispeech]

Please see [RESULTS.md](https://github.com/k2-fsa/icefall/blob/master/egs/librispeech/ASR/RESULTS.md)
for the **latest** results.

#### [Conformer CTC](https://github.com/k2-fsa/icefall/tree/master/egs/librispeech/ASR/conformer_ctc)

|     | test-clean | test-other |
|-----|------------|------------|
| WER | 2.42       | 5.73       |


We provide a Colab notebook to test the pre-trained model: [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/drive/1huyupXAcHsUrKaWfI83iMEJ6J0Nh0213?usp=sharing)

#### [TDNN LSTM CTC](https://github.com/k2-fsa/icefall/tree/master/egs/librispeech/ASR/tdnn_lstm_ctc)

|     | test-clean | test-other |
|-----|------------|------------|
| WER | 6.59       | 17.69      |

We provide a Colab notebook to test the pre-trained model: [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/drive/1-iSfQMp2So-We_Uu49N4AAcMInB72u9z?usp=sharing)


#### [Transducer (Conformer Encoder + LSTM Predictor)](https://github.com/k2-fsa/icefall/tree/master/egs/librispeech/ASR/transducer)

|               | test-clean | test-other |
|---------------|------------|------------|
| greedy_search | 3.07       | 7.51       |

We provide a Colab notebook to test the pre-trained model: [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/drive/1_u6yK9jDkPwG_NLrZMN2XK7Aeq4suMO2?usp=sharing)

#### [Transducer (Conformer Encoder + Stateless Predictor)](https://github.com/k2-fsa/icefall/tree/master/egs/librispeech/ASR/transducer)

|                                       | test-clean | test-other |
|---------------------------------------|------------|------------|
| modified_beam_search (`beam_size=4`) | 2.56       | 6.27       |


We provide a Colab notebook to test the pre-trained model: [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/drive/1CO1bXJ-2khDckZIW8zjOPHGSKLHpTDlp?usp=sharing)


#### [Transducer (Zipformer Encoder + Stateless Predictor)](https://github.com/k2-fsa/icefall/tree/master/egs/librispeech/ASR/zipformer)

WER (modified_beam_search `beam_size=4` unless further stated) 

1. LibriSpeech-960hr

| Encoder         | Params | test-clean | test-other | epochs  | devices    |
|-----------------|--------|------------|------------|---------|------------|
| Zipformer       | 65.5M  | 2.21       | 4.79       | 50      | 4 32G-V100 |
| Zipformer-small | 23.2M  | 2.42       | 5.73       | 50      | 2 32G-V100 |
| Zipformer-large | 148.4M | 2.06       | 4.63       | 50      | 4 32G-V100 |
| Zipformer-large | 148.4M | 2.00       | 4.38       | 174     | 8 80G-A100 |

2. LibriSpeech-960hr + GigaSpeech

| Encoder         | Params | test-clean | test-other |
|-----------------|--------|------------|------------|
| Zipformer       | 65.5M   | 1.78       | 4.08       |


3. LibriSpeech-960hr + GigaSpeech + CommonVoice

| Encoder         | Params | test-clean | test-other |
|-----------------|--------|------------|------------|
| Zipformer       | 65.5M   | 1.90       | 3.98       |


### [GigaSpeech][gigaspeech]

#### [Conformer CTC](https://github.com/k2-fsa/icefall/tree/master/egs/gigaspeech/ASR/conformer_ctc)

|     |  Dev  | Test  |
|-----|-------|-------|
| WER | 10.47 | 10.58 |

#### [Transducer (pruned_transducer_stateless2)](https://github.com/k2-fsa/icefall/tree/master/egs/gigaspeech/ASR/pruned_transducer_stateless2)

Conformer Encoder + Stateless Predictor + k2 Pruned RNN-T Loss

|                      |  Dev  | Test  |
|----------------------|-------|-------|
|    greedy_search     | 10.51 | 10.73 |
|   fast_beam_search   | 10.50 | 10.69 |
| modified_beam_search | 10.40 | 10.51 |

#### [Transducer (Zipformer Encoder + Stateless Predictor)](https://github.com/k2-fsa/icefall/tree/master/egs/gigaspeech/ASR/zipformer)

|                      |  Dev  | Test  |
|----------------------|-------|-------|
|    greedy_search     | 10.31 | 10.50 |
|   fast_beam_search   | 10.26 | 10.48 |
| modified_beam_search | 10.25 | 10.38 |


### [Aishell][aishell]

#### [TDNN LSTM CTC](https://github.com/k2-fsa/icefall/tree/master/egs/aishell/ASR/tdnn_lstm_ctc)

|     | test  |
|-----|-------|
| CER | 10.16 |

We provide a Colab notebook to test the pre-trained model:  [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/drive/1jbyzYq3ytm6j2nlEt-diQm-6QVWyDDEa?usp=sharing)

#### [Transducer (Conformer Encoder + Stateless Predictor)](https://github.com/k2-fsa/icefall/tree/master/egs/aishell/ASR/transducer_stateless)

|     | test |
|-----|------|
| CER | 4.38 |

We provide a Colab notebook to test the pre-trained model: [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/drive/14XaT2MhnBkK-3_RqqWq3K90Xlbin-GZC?usp=sharing)

#### [Transducer (Zipformer Encoder + Stateless Predictor)](https://github.com/k2-fsa/icefall/tree/master/egs/aishell/ASR/zipformer)

WER (modified_beam_search `beam_size=4`) 

| Encoder         | Params | dev | test | epochs  |
|-----------------|--------|-----|------|---------|
| Zipformer       | 73.4M  | 4.13| 4.40 | 55      |
| Zipformer-small | 30.2M  | 4.40| 4.67 | 55      |
| Zipformer-large | 157.3M | 4.03| 4.28 | 56      |


### [Aishell4][aishell4]

#### [Transducer (pruned_transducer_stateless5)](https://github.com/k2-fsa/icefall/tree/master/egs/aishell4/ASR/pruned_transducer_stateless5)

1 Trained with all subsets: 
|     |   test     |
|-----|------------|
| CER |   29.08    |

We provide a Colab notebook to test the pre-trained model: [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/drive/1z3lkURVv9M7uTiIgf3Np9IntMHEknaks?usp=sharing)


### [TIMIT][timit]

#### [TDNN LSTM CTC](https://github.com/k2-fsa/icefall/tree/master/egs/timit/ASR/tdnn_lstm_ctc)

|   |TEST|
|---|----|
|PER| 19.71% |

We provide a Colab notebook to test the pre-trained model: [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/drive/1Hs9DA4V96uapw_30uNp32OMJgkuR5VVd?usp=sharing)

#### [TDNN LiGRU CTC](https://github.com/k2-fsa/icefall/tree/master/egs/timit/ASR/tdnn_ligru_ctc)

|   |TEST|
|---|----|
|PER| 17.66% |

We provide a Colab notebook to test the pre-trained model: [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/drive/1z3lkURVv9M7uTiIgf3Np9IntMHEknaks?usp=sharing)


### [TED-LIUM3][tedlium3]

#### [Transducer (Conformer Encoder + Stateless Predictor)](https://github.com/k2-fsa/icefall/tree/master/egs/tedlium3/ASR/transducer_stateless)

|                                      |  dev  |  test  |
|--------------------------------------|-------|--------|
| modified_beam_search (`beam_size=4`) |  6.91 |  6.33  |


We provide a Colab notebook to test the pre-trained model: [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/drive/1MmY5bBxwvKLNT4A2DJnwiqRXhdchUqPN?usp=sharing)

#### [Transducer (pruned_transducer_stateless)](https://github.com/k2-fsa/icefall/tree/master/egs/tedlium3/ASR/pruned_transducer_stateless)

|                                      |  dev  |  test  |
|--------------------------------------|-------|--------|
| modified_beam_search (`beam_size=4`) |  6.77 |  6.14  |

We provide a Colab notebook to test the pre-trained model: [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/drive/1je_1zGrOkGVVd4WLzgkXRHxl-I27yWtz?usp=sharing)


### [Aidatatang_200zh][aidatatang_200zh]

#### [Transducer (pruned_transducer_stateless2)](https://github.com/k2-fsa/icefall/tree/master/egs/aidatatang_200zh/ASR/pruned_transducer_stateless2)

|                      |  Dev  | Test  |
|----------------------|-------|-------|
|    greedy_search     | 5.53  | 6.59  |
|   fast_beam_search   | 5.30  | 6.34  |
| modified_beam_search | 5.27  | 6.33  |

We provide a Colab notebook to test the pre-trained model: [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/drive/1wNSnSj3T5oOctbh5IGCa393gKOoQw2GH?usp=sharing)


### [WenetSpeech][wenetspeech]

#### [Transducer (pruned_transducer_stateless2)](https://github.com/k2-fsa/icefall/tree/master/egs/wenetspeech/ASR/pruned_transducer_stateless2)

|                      |  Dev  | Test-Net | Test-Meeting |
|----------------------|-------|----------|--------------|
|    greedy_search     | 7.80  |  8.75    |  13.49       |
|   fast_beam_search   | 7.94  |  8.74    |  13.80       |
| modified_beam_search | 7.76  |  8.71    |  13.41       |

We provide a Colab notebook to test the pre-trained model: [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/drive/1EV4e1CHa1GZgEF-bZgizqI9RyFFehIiN?usp=sharing)

#### [Transducer **Streaming** (pruned_transducer_stateless5) ](https://github.com/k2-fsa/icefall/tree/master/egs/wenetspeech/ASR/pruned_transducer_stateless5)

|                      |  Dev  | Test-Net | Test-Meeting |
|----------------------|-------|----------|--------------|
| greedy_search | 8.78 | 10.12 | 16.16 |
| fast_beam_search| 9.01 | 10.47 | 16.28 |
| modified_beam_search | 8.53| 9.95 | 15.81 |


### [Alimeeting][alimeeting]

#### [Transducer (pruned_transducer_stateless2)](https://github.com/k2-fsa/icefall/tree/master/egs/alimeeting/ASR/pruned_transducer_stateless2)

|                      |  Eval  | Test-Net |
|----------------------|--------|----------|
|    greedy_search     | 31.77  |  34.66   |
|   fast_beam_search   | 31.39  |  33.02   |
| modified_beam_search | 30.38  |  34.25   |

We provide a Colab notebook to test the pre-trained model: [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/drive/1tKr3f0mL17uO_ljdHGKtR7HOmthYHwJG?usp=sharing)


### [TAL_CSASR][tal_csasr]


#### [Transducer (pruned_transducer_stateless5)](https://github.com/k2-fsa/icefall/tree/master/egs/tal_csasr/ASR/pruned_transducer_stateless5)

The best results for Chinese CER(%) and English WER(%) respectively (zh: Chinese, en: English):
|decoding-method | dev | dev_zh | dev_en | test | test_zh | test_en |
|--|--|--|--|--|--|--|
|greedy_search| 7.30 | 6.48 | 19.19 |7.39| 6.66 | 19.13|
|fast_beam_search| 7.18 | 6.39| 18.90 |  7.27| 6.55 | 18.77|
|modified_beam_search| 7.15 | 6.35 | 18.95 | 7.22| 6.50 | 18.70 |

We provide a Colab notebook to test the pre-trained model: [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/drive/1DmIx-NloI1CMU5GdZrlse7TRu4y3Dpf8?usp=sharing)

## TTS: Text-to-Speech

### Supported Datasets

  - [LJSpeech][ljspeech]
  - [VCTK][vctk]
  - [LibriTTS][libritts_tts]

### Supported Models

  - [VITS](https://arxiv.org/abs/2106.06103)

# Deployment with C++

Once you have trained a model in icefall, you may want to deploy it with C++ without Python dependencies.

Please refer to

  - https://k2-fsa.github.io/icefall/model-export/export-with-torch-jit-script.html
  - https://k2-fsa.github.io/icefall/model-export/export-onnx.html
  - https://k2-fsa.github.io/icefall/model-export/export-ncnn.html

for how to do this.

We also provide a Colab notebook, showing you how to run a torch scripted model in [k2][k2] with C++.
Please see: [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/drive/1BIGLWzS36isskMXHKcqC9ysN6pspYXs_?usp=sharing)


[yesno]: egs/yesno/ASR
[librispeech]: egs/librispeech/ASR
[aishell]: egs/aishell/ASR
[aishell2]: egs/aishell2/ASR
[aishell4]: egs/aishell4/ASR
[timit]: egs/timit/ASR
[tedlium3]: egs/tedlium3/ASR
[gigaspeech]: egs/gigaspeech/ASR
[aidatatang_200zh]: egs/aidatatang_200zh/ASR
[wenetspeech]: egs/wenetspeech/ASR
[alimeeting]: egs/alimeeting/ASR
[tal_csasr]: egs/tal_csasr/ASR
[ami]: egs/ami
[swbd]: egs/swbd/ASR
[k2]: https://github.com/k2-fsa/k2
[commonvoice]: egs/commonvoice/ASR
[csj]: egs/csj/ASR
[libricss]: egs/libricss/SURT
[libritts_asr]: egs/libritts/ASR
[libriheavy]: egs/libriheavy/ASR
[mgb2]: egs/mgb2/ASR
[spgispeech]: egs/spgispeech/ASR
[voxpopuli]: egs/voxpopuli/ASR
[xbmu-amdo31]: egs/xbmu-amdo31/ASR

[vctk]: egs/vctk/TTS
[ljspeech]: egs/ljspeech/TTS
[libritts_tts]: egs/libritts/TTS

## Acknowledgements

Some contributors to this project were supported by Xiaomi Corporation. Others were supported by National Science Foundation CCRI award 2120435.  This is not an exhaustive list of sources of support.