chaiwatt/LeKa-model

LeKa model — OpenThai2.0 ASR Streaming (ONNX)

Thai streaming speech-to-text model files used by the LeKa desktop app. The app downloads them on first run and runs them locally with ONNX Runtime; no audio leaves the computer.

This is an ONNX export of iapp/OpenThai2.0-ASR-Streaming by iApp, a Thai fine-tune of NVIDIA nemotron-3.5-asr-streaming-0.6b. The weights are unchanged (FP32); only the file format differs.

Files

file	what it is
encoder.onnx + encoder.onnx.data	cache-aware FastConformer encoder, one streaming step; language prompt and joint encoder projection included
decoder.onnx	RNN-T prediction network (2-layer LSTM) + joint prediction projection
joint.onnx	joint network → logits (14,988 tokens + blank)
frontend.json, mel_fb.bin, window.bin	exact log-mel front-end constants (128 mels, n_fft 512, hop 160, pre-emphasis 0.97)
model.json	streaming constants (chunk/shift sizes, cache shapes, prompt ids, blank id)
tokens.json	vocabulary

Latency setting: 560 ms (att_context_size [56, 6]). Greedy decoding, max 2 symbols per frame, blank offset applied at decode time (−2.0 conversation, −1.0 standard).

Checked against the original NeMo decoder: identical text on all test clips.

Licence and credit

Released under the OpenMDW License Agreement, version 1.1 (see LICENSE), the same licence as the original model. Model by iApp Technology (OpenThai), built on NVIDIA Nemotron. All credit for training goes to them; this repository only repackages the model for ONNX Runtime.

Speaker labels

speaker.onnx + speaker_frontend.json, speaker_mel_fb.bin, speaker_window.bin: ONNX export of NVIDIA TitaNet-Large (speaker embeddings, 192-d), licensed CC-BY-4.0 by NVIDIA. LeKa uses it to tell speakers apart in a room meeting. Weights unchanged.