musetric/whisper-large-v3-onnx

Whisper large-v3 — word-timestamped ONNX (q4 / WebGPU)

ONNX export of openai/whisper-large-v3 in the transformers.js layout, with the cross-attention alignment heads baked into generation_config.json so the decoder emits word-level timestamps (return_timestamps: 'word'). Packaged for the musetric packages/ai runtime (@huggingface/transformers on the WebGPU execution provider).

onnx-community publishes such _timestamped variants for turbo, small and tiny, but not for large-v3 — hence this export. It is produced by scripts/onnx/whisper in musetric-toolkit (optimum + the transformers.js converter).

Files

file	role
encoder_model_q4.onnx	audio encoder (q4)
decoder_model_merged_q4.onnx	decoder with merged KV-cache (q4)
config.json, generation_config.json, preprocessor_config.json	model / feature-extractor config
tokenizer.json, tokenizer_config.json, vocab.json, merges.txt, added_tokens.json, special_tokens_map.json, normalizer.json	tokenizer

Only the q4 graphs are shipped; the runtime loads dtype: 'q4' for both the encoder and the merged decoder.

How to use

import { pipeline } from '@huggingface/transformers';

const asr = await pipeline(
  'automatic-speech-recognition',
  'musetric/whisper-large-v3-onnx',
  {
    device: 'webgpu',
    subfolder: '',
    dtype: { encoder_model: 'q4', decoder_model_merged: 'q4' },
  },
);
const out = await asr(audio, { return_timestamps: 'word', chunk_length_s: 30 });

Intended uses & limitations

Intended: client/edge speech-to-text with word timings via WebGPU through @huggingface/transformers — e.g. lyric alignment in musetric.

Limitations:

• Requires a WebGPU adapter with shader-f16.
• q4 weight quantization trades a little accuracy for size/speed; for non-English audio quality varies (the musetric pipeline adds language forcing and loop guards on top).
• Word timestamps come from the whisper cross-attention heads, not a separate forced aligner.

Source & lineage

Documented only as far as it is verifiable.

• Base weights: openai/whisper-large-v3 @ 06f233fe06e710322aca913c1bc4249a0d71fce1. Inference-only re-export in the transformers.js layout; no fine-tuning.
• Alignment heads: the [layer, head] pairs correlated with word timing come from hollance's gist, which covers tiny through large-v2. large-v3 is absent there, so its heads are taken from the generation_config.json of the base model itself.
• Converter: the transformers.js converter plus optimum, pinned to transformers==4.42.4 / optimum==1.21.3 / torch==2.4.1 (transformers 4.43 adds a cache_position decoder input that @huggingface/transformers 4.2.0 does not feed).
• Export tooling: scripts/onnx/whisper in musetric-toolkit.

License

Apache-2.0, following the model card the weights are downloaded from.

Upstream is inconsistent here and it is worth knowing: the openai/whisper repository states that "Whisper's code and model weights are released under the MIT License", while the Hugging Face model card these weights are actually fetched from declares apache-2.0. This export follows the source it downloads from; consult both before relying on either.