---
license: apache-2.0
language:
- fa
pipeline_tag: automatic-speech-recognition
library_name: omnilingual-asr
tags:
- speech
- automatic-speech-recognition
- asr
- persian
- farsi
- omnilingual-asr
- wav2vec2
- ctc
- fairseq2
base_model: facebook/omniASR-CTC-3B
datasets:
- facebook/omnilingual-asr-corpus
metrics:
- cer
- wer
---

# Rade-ASR-CTC-3B-fa

**Persian (Farsi) fine-tuned** version of Meta AI's **[Omnilingual ASR](https://github.com/facebookresearch/omnilingual-asr) CTC-3B** model, released and maintained by **[Rade AI](https://huggingface.co/RadeAI)**.

<div align="center">
  <a href="https://huggingface.co/RadeAI/Rade-ASR-CTC-3B-fa">🤗 Model</a> |
  <a href="https://github.com/facebookresearch/omnilingual-asr">🐙 Base (Omnilingual ASR)</a> |
  <a href="https://huggingface.co/RadeAI/Rade-ASR-CTC-3B-fa/blob/main/notebook.ipynb">📓 Notebook</a>
</div>

<div align="center">
  <a href="https://huggingface.co/RadeAI/Rade-ASR-CTC-3B-fa/colab"><img src="https://colab.research.google.com/assets/colab-badge.svg" alt="Open in Colab"></a>
</div>

> **TL;DR** — A fast, non-autoregressive (CTC) speech-to-text model specialized for **Persian**, built on top of Meta's 3-billion-parameter Omnilingual ASR encoder. It transcribes Persian audio clips (≤ 40 s) and runs **~199× faster than real time** in fp16 on a single RTX 4090. On Persian test sets it reaches **CER ≈ 4 %** on FLEURS (clean read speech) and **≈ 18 %** on Common Voice (noisier, crowd-sourced) — normalized.

---

## Model description

| | |
|---|---|
| **Base model** | `facebook/omniASR-CTC-3B` (Omnilingual ASR, `omniASR_CTC_3B_v2`) |
| **Architecture** | Wav2Vec2-style encoder + CTC head |
| **Parameters** | ~3.08 B (3,080,423,636) |
| **Fine-tuned for** | Persian / Farsi (`pes_Arab`) |
| **Task** | Automatic Speech Recognition (speech → text) |
| **Toolkit** | [fairseq2](https://github.com/facebookresearch/fairseq2) via the `omnilingual-asr` package |
| **License** | Apache-2.0 |

This checkpoint takes the strong multilingual representations of Omnilingual ASR's 3B CTC encoder and adapts them to Persian, giving accurate, low-latency transcription for Iranian Persian.

## Evaluation

Measured by Rade with greedy CTC decoding (fp16) on two standard Persian test sets. Both reference and hypothesis are normalized before scoring — unify `ك→ک` / `ي→ی`, convert ZWNJ (نیم‌فاصله) to space, strip punctuation and diacritics, collapse whitespace — so that orthography-only differences don't count as errors.

| Test set | Clips | WER | CER |
|---|---|---|---|
| **FLEURS** `fa_ir` — read speech | 871 | 19.6 % | **4.4 %** |
| **VisualEars golden** `fa` — curated (clean/farfield/obstructed) | 6,669 | 22.9 % | **4.3 %** |
| **Common Voice 17.0** `fa` — crowd-sourced | 10,355 | 21.8 % | 17.8 % |

> **CER is the more faithful metric for Persian.** Persian **WER** is inflated by orthographic/spacing variation (نیم‌فاصله/ZWNJ, affix spacing, compound spelling) that doesn't reflect actual mis-recognition — note FLEURS sits at **19.6 % WER but only 4.4 % CER**, i.e. most "word errors" are one-character spelling differences. On clean, well-curated speech (FLEURS, VisualEars) the model reaches **CER ≈ 4 %**, and it stays robust across recording conditions (VisualEars far-field 4.5 % / obstructed 4.2 % CER). On noisier crowd-sourced audio (Common Voice — spontaneous speech, varied mics/accents, loan words) CER rises to **≈ 18 %**.

## Speed & hardware

CTC models are **non-autoregressive** — they decode a whole clip in one forward pass, so they're very fast. Measured by Rade on a single **RTX 4090** (8.8 s Persian clip, `batch_size=1`):

| Precision | Inference latency | Speed | Peak VRAM |
|---|---|---|---|
| **FP16** (recommended) | **44 ms** | **~199× real time** | **6.4 GB** |
| FP32 | 102 ms | ~87× real time | 12.7 GB |

FP16 and FP32 produce **identical transcripts**, so FP16 is the recommended default (half the VRAM, ~2× faster). Batched throughput on the 4090 reaches **~208× real time** (the 222-min FLEURS set transcribes in ~64 s). A **16 GB GPU** (e.g. Colab T4 / L4) is enough for fp16. CPU works but is slow.

## Files in this repo

| File | What it is | Size | When to use |
|---|---|---|---|
| **`model_fp16.pt`** | Consolidated **fp16** weights, single file | **~6.2 GB** | **Recommended.** Smaller, faster download; fp16 inference. |
| `pp_00/tp_00/sdp_00.pt`, `sdp_01.pt` | Original **fp32** FSDP checkpoint shards | ~12 GB | If you want full fp32 precision weights. |
| `config.json` | Model metadata (arch, tokenizer, vocab) | — | Read by tooling; you don't load it directly. |
| `notebook.ipynb` | Ready-to-run Colab/Kaggle notebook | — | One-click demo (powers the "Open in Colab" button). |

> Both weight files produce **identical transcripts** at fp16. The single `model_fp16.pt` is just half the download — prefer it unless you specifically need the fp32 master weights.

## Usage

**1) Install the Omnilingual ASR runtime** (the model loads through fairseq2's asset system):

```bash
# system dependency for audio I/O
sudo apt-get install -y libsndfile1   # (Linux)  /  brew install libsndfile (macOS)

# Need omnilingual-asr 0.2.0 (it registers the 3b_v2 architecture this model uses).
# --ignore-requires-python: 0.2.0's metadata caps python at "<=3.12" (read as <=3.12.0), which
# wrongly excludes Python 3.12.x (e.g. Colab). The flag installs it anyway; it runs fine on 3.12.
pip install --ignore-requires-python omnilingual-asr==0.2.0 huggingface_hub
# Pin the whole torch stack to the CUDA 12.8 build that fairseq2 needs.
# (Without this you hit `libcudart.so.13` / torchvision::nms errors from a mismatched torchaudio/torchvision.)
pip install torch==2.8.0 torchaudio==2.8.0 torchvision==0.23.0 --index-url https://download.pytorch.org/whl/cu128
# On Colab/Jupyter, restart the runtime once after this install.
```

**2) Download the weights + register a fairseq2 asset card** that points at them, reusing Omnilingual ASR's official Persian-capable tokenizer. The asset card's `checkpoint:` can point at **either** the single `model_fp16.pt` file **or** the shard directory — both work.

```python
import pathlib, torch
from huggingface_hub import hf_hub_download

# --- Recommended: download ONLY the single fp16 file (~6.2 GB) ---
ckpt = hf_hub_download("RadeAI/Rade-ASR-CTC-3B-fa", "model_fp16.pt")

# --- Alternative: full fp32 shards (~12 GB) ---
# from huggingface_hub import snapshot_download
# ckpt = snapshot_download("RadeAI/Rade-ASR-CTC-3B-fa", allow_patterns=["pp_00/tp_00/*"])

# Register a fairseq2 asset card pointing at the downloaded checkpoint
asset_dir = pathlib.Path.home() / ".config/fairseq2/assets"
asset_dir.mkdir(parents=True, exist_ok=True)
(asset_dir / "rade.yaml").write_text(f"""\
name: rade_CTC_3B_fa
model_family: wav2vec2_asr
model_arch: 3b_v2
checkpoint: "{ckpt}"
tokenizer_ref: omniASR_tokenizer_written_v2
""")
```

**3) Transcribe** (clips must be **< 40 s**):

```python
from omnilingual_asr.models.inference.pipeline import ASRInferencePipeline
pipe = ASRInferencePipeline(
    model_card="rade_CTC_3B_fa",
    device="cuda" if torch.cuda.is_available() else "cpu",
    dtype=torch.float16,   # fp16: ~199x real time, 6.4 GB VRAM, identical output to fp32
)
text = pipe.transcribe(["sample_fa.wav"], lang=["pes_Arab"], batch_size=1)
print(text[0])
```

A ready-to-run notebook is provided: **[`notebook.ipynb`](https://huggingface.co/RadeAI/Rade-ASR-CTC-3B-fa/blob/main/notebook.ipynb)** — or just click **[Open in Colab](https://huggingface.co/RadeAI/Rade-ASR-CTC-3B-fa/colab)** (also in the **"Use this model"** menu at the top of this page).

## Limitations

- **Audio length:** CTC models accept clips **shorter than 40 seconds**. For longer audio, split into < 40 s chunks (e.g. on silence) and concatenate the results.
- **Domain:** best on clear Persian speech; very noisy audio or heavy code-switching may degrade accuracy.
- **Language code:** use `pes_Arab` (Western/Iranian Persian). Note that for CTC models the `lang` argument is informational — CTC decoding is language-agnostic at inference time.

## License & attribution

Released under **Apache-2.0**, consistent with the base Omnilingual ASR model and code. This is a derivative fine-tune of `facebook/omniASR-CTC-3B`; all credit for the base architecture and pre-training goes to the Meta AI Omnilingual ASR Team.

```bibtex
@misc{omnilingualasr2025,
  title={{Omnilingual ASR}: Open-Source Multilingual Speech Recognition for 1600+ Languages},
  author={{Omnilingual ASR Team}},
  year={2025},
  url={https://ai.meta.com/research/publications/omnilingual-asr-open-source-multilingual-speech-recognition-for-1600-languages/}
}
```

## Contact

Built and maintained by **Rade AI**. For questions, collaboration, or custom Persian speech/NLP models, get in touch:

- **Telegram:** [@Rade_admin](https://t.me/Rade_admin)
- **Phone:** +98 936 864 7499
- **Hugging Face:** [RadeAI](https://huggingface.co/RadeAI)

---

<div dir="rtl">

## معرفی (فارسی)

این مدل نسخه‌ی **فاین‌تیون‌شده روی زبان فارسی** از مدل **Omnilingual ASR CTC-3B** شرکت متا است که توسط **[راده](https://huggingface.co/RadeAI)** منتشر شده.

- گفتار فارسی را به متن تبدیل می‌کند (کلیپ‌های کوتاه‌تر از ۴۰ ثانیه).
- معماری **CTC** (غیر-اتورگرسیو) دارد، برای همین خیلی سریع است — در fp16 حدود **۱۹۹ برابر سریع‌تر از زمان واقعی** روی یک RTX 4090.
- در fp16 فقط **۶.۴ گیگابایت VRAM** می‌خواهد (یک GPU ۱۶ گیگ کافی است).
- دقت (با نرمال‌سازیِ متن): روی **FLEURS** فارسی (گفتارِ تمیز) **CER حدود ۴٪** (WER ۱۹.۶٪)، و روی **Common Voice 17** فارسی (داده‌ی محاوره‌ایِ نویزی، ۱۰٬۳۵۵ کلیپ) **CER حدود ۱۸٪** (WER ۲۱.۸٪). در فارسی CER معیارِ معتبرتریه چون WER با اختلافِ املایی/نیم‌فاصله متورم می‌شه.

نحوه‌ی استفاده در بخش انگلیسیِ بالا آمده. برای تستِ سریع، دکمه‌ی **Open in Colab** (بالای همین صفحه، منوی «Use this model») یا نوت‌بوکِ `notebook.ipynb` رو باز کن.

**ارتباط با راده:** تلگرام [@Rade_admin](https://t.me/Rade_admin) — تلفن: ۰۹۳۶۸۶۴۷۴۹۹

</div>