FunASR is an open-source end-to-end speech recognition toolkit developed by the Speech Lab of DAMO Academy, Alibaba Group. Its mission is to bridge the gap between academic research and industrial applications by providing pre-trained models on large-scale industrial corpora, comprehensive training/finetuning pipelines, and production-ready deployment runtim...
- Overview
- Architecture & Design
- Core Pipeline Stages (run.sh)
- Key Modules
- paraformer — Flagship ASR Model
- FSMN-VAD — Voice Activity Detection
- CT-Transformer — Punctuation & Disfluency
- fun-codec — Neural Speech Codec Extension
FunASR — Fundamental End-to-End Speech Recognition Toolkit
Alibaba DAMO Speech Lab | arXiv 2305.11013 | GitHub: alibaba-damo-academy/FunASR
Overview
FunASR is an open-source end-to-end speech recognition toolkit developed by the Speech Lab of DAMO Academy, Alibaba Group. Its mission is to bridge the gap between academic research and industrial applications by providing pre-trained models on large-scale industrial corpora, comprehensive training/finetuning pipelines, and production-ready deployment runtimes.
The flagship model is paraformer, a non-autoregressive (NAR) transformer trained on 60,000 hours of manually annotated Mandarin speech — a scale far exceeding academic benchmarks.
Architecture & Design
┌─────────────────────────────────────────────────────────┐
│ ModelScope │
│ Paraformer │ FSMN-VAD │ CT-Transformer │ FunCodec │ ... │
├─────────────────────────────────────────────────────────┤
│ FunASR Toolkit │
│ │
│ Academic Pipeline (run.sh): │
│ data_prep → feat_extract → dict_gen → train → infer │
│ │
│ Industrial Pipeline: │
│ infer.sh │ finetune.sh │
├─────────────────────────────────────────────────────────┤
│ Runtime Backends │
│ CPU/GPU │ ONNX │ Libtorch │ TensorRT │
├─────────────────────────────────────────────────────────┤
│ Production Deployment │
└─────────────────────────────────────────────────────────┘
Core Pipeline Stages (run.sh)
- Stage 0 — Data preparation
- Stage 1 — Feature extraction (80-dim Mel-filterbank)
- Stage 2 — Dictionary generation
- Stage 3-4 — Model training
- Stage 5 — Inference and scoring
Key Modules
paraformer — Flagship ASR Model
- Single-step NAR transformer with CIF predictor + GLM sampler
- Trained on 60k hrs Mandarin industrial data
- Comparable to AR transformer accuracy, 10x+ inference speedup
- Added extensions: timestamp prediction, hotword customization
FSMN-VAD — Voice Activity Detection
- Feedforward Sequential Memory Network-based VAD
- Uses monophones as modeling units for richer speech info
- Post-processing: threshold settings + sliding windows
- Tested on meeting (2hr) and video (4hr) domains
- Reduces CER by filtering non-speech: video domain CER 27.87% → 25.34%
CT-Transformer — Punctuation & Disfluency
- Controllable Time-delay Transformer for real-time text postprocessing
- Handles punctuation insertion and speech disfluency removal
- Supports partial output freezing with controllable time delay
- Fast decoding strategy for minimal latency
fun-codec — Neural Speech Codec Extension
- Extension toolkit for SoundStream, Encodec, FreqCodec
- Reproducible training recipes + 7 pre-trained models
- Frequency-domain codec (FreqCodec): comparable quality, lower compute
- Downstream: ASR, personalized TTS
seaco-paraformer — Contextual Hotword Extension
- CIF-based contextual module for decoupled hotword prediction
- Attention Score Filtering (ASF) for large-scale hotword lists
- +58% F1 improvement on AISHELL-1 named entity subtest
sa-paraformer — Speaker-Attributed ASR Extension
- Extends Paraformer for multi-speaker meeting transcription
- Speaker-filling strategy + inter-CTC enhancement
- 6.1% relative SD-CER improvement over cascaded models
paraformer-v2 — Noise-Robust Multilingual Upgrade
- Replaces CIF with CTC-based token predictor
- Addresses CIF's BPE tokenization and noise sensitivity issues
- Up to 14% WER reduction on English datasets
Benchmark Summary
| Dataset | Paraformer CER | AR Transformer CER | RTF (Paraformer) | RTF (AR) |
|---|---|---|---|---|
| AISHELL-1 test | 5.2% | 5.4% | 0.0037 | 0.0230 |
| AISHELL-2 test ios | 6.19% | 6.23% | 0.0026 | 0.0168 |
| Industrial 20k hrs (far-field) | 13.94% | 14.72% | — | — |
| Industrial 20k hrs (common) | 7.97% | 8.66% | — | — |
Timestamp prediction (Paraformer-TP vs force-alignment): - AISHELL: AAS 71.0ms vs 80.1ms (FA) - Industrial: AAS 65.3ms vs 60.3ms (FA), gap <10ms
Deployment & Ecosystem
- Runtime: ONNX, Libtorch, TensorRT for CPU/GPU/Android/iOS
- AMP Quantization: Accelerated inference with mixed-precision
- ModelScope: Hosts all pre-trained models for one-click access
- Multilingual: English, French, German, Spanish, Russian, Japanese, Korean, etc.
Relationships
- paraformer — Core ASR architecture
- seaco-paraformer — Hotword customization extension
- sa-paraformer — Speaker-attributed multi-speaker extension
- paraformer-v2 — CTC-based successor for noise-robust multilingual
- fun-codec — Neural codec toolkit extension
- qwen3-asr — Alibaba's LLM-based ASR (2026), different architectural approach
- nim4-asr — NIO's LLM-based ASR (2026), production-grade alternative
References
- arXiv 2206.08317 — Paraformer (2022-06)
- arXiv 2305.11013 — FunASR Toolkit (2023-05)
- arXiv 2308.03266 — SeACo-Paraformer (2023-08)
- arXiv 2309.07405 — FunCodec (2023-09)
- arXiv 2310.04863 — SA-Paraformer (2023-10)
- arXiv 2409.17746 — Paraformer-v2 (2024-09)
- GitHub: github.com/alibaba-damo-academy/FunASR
- GitHub: github.com/alibaba-damo-academy/FunCodec