| --- |
| library_name: pytorch |
| license: apache-2.0 |
| --- |
| |
| # Conformer-CTC Small (Ambarella N1-655 CVflow v3 NVP) |
|
|
| Conformer-CTC Small is a convolution-augmented Transformer speech recognition model trained with Connectionist Temporal Classification (CTC) loss for English automatic speech recognition (ASR). |
|
|
| Original paper: [Conformer: Convolution-augmented Transformer for Speech Recognition](https://arxiv.org/abs/2005.08100) |
|
|
| Model Configuration: |
| - Reference implementation: [https://github.com/NVIDIA/NeMo](https://github.com/NVIDIA/NeMo) |
| - Original Weight: [https://huggingface.co/csukuangfj/sherpa-onnx-nemo-ctc-en-conformer-small](https://huggingface.co/csukuangfj/sherpa-onnx-nemo-ctc-en-conformer-small) |
| - Dataset: NeMo ASRSet (LibriSpeech, Fisher, Switchboard, WSJ, NSC, Mozilla Common Voice) |
| - License: Apache-2.0 (`LICENSE`) |
| - Support Cooper version: |
| - CNNGen: `[3.9.0 / n1-655x]` (`cavalry_gen 3.0.4`) |
|
|
| ## Upstream Attribution & Modification Notice |
| - **Upstream Copyright**: Copyright (c) NVIDIA CORPORATION & Affiliates (NVIDIA NeMo `stt_en_conformer_ctc_small`) and Copyright (c) Xiaomi Corporation / `sherpa-onnx` contributors (`csukuangfj/sherpa-onnx-nemo-ctc-en-conformer-small`), licensed under the Apache License, Version 2.0. |
| - **Modification Notice (Apache-2.0 Section 4(b))**: Modified by Ambarella International LLC (2026). Fixed dynamic time dimension to static `[1, 80, 1024]` (10.24 s window), quantized to mixed FP16/INT8 via Ambarella CNNGen (`onnx_surgery` -> `vas` -> `cavalry_gen 3.0.4`), and compiled to CVflow v3 N1-655 (`vdg_arch = 0xB`) Cavalry DAG binary format (`n1-655_conformer_ctc_small_amba_optimized.bin`). |
|
|
| ## NVP Port & Runtime Specification |
| - **Target SoC**: Ambarella N1-655 (`vdg_arch = 0xB`, CVflow v3 `cavalry_gen` 3.0.4) |
| - **Input port**: `audio_signal` `[1, 80, 1024]` IEEE FP16 (16 kHz PCM -> 80-bin Kaldi log-Mel, 25 ms Povey window, 10 ms hop, per-feature mean/std normalized) |
| - **Output port**: `logprobs` `[1, 256, 1025]` IEEE FP16 (CTC greedy decode with blank ID `1024` against `tokens.txt`) |
|
|
| | Model | Device | Compression | Model Link | |
| | :---: | :---: | :---: | :--- | |
| | Conformer | N1-655 | Amba_optimized | [Model_Link](https://huggingface.co/cchiou-amba/Conformer/blob/main/n1-655_conformer_ctc_small_amba_optimized.bin) | |
| |
