Hacker News AI · 2026/10/13 19:27:14

谷歌 EmbeddingGemma 2 改造为本地语音转文字:MacBook Air 13 秒转录 1 小时音频,仅训练轻量读取器

原标题:An hour of audio transcribed in about 13s on MacBook Air
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核心综述

开发者将谷歌多模态嵌入模型 EmbeddingGemma 2 改造为高性能本地语音转文字工具,在基础款 MacBook Air 上实现 1 小时音频仅需约 13 秒完成转录。该方案冻结原始音频编码器,仅训练一个轻量级“读取器”将音频切片映射至文本空间并匹配最近词汇,全程在 Apple Neural Engine 运行且数据不出设备。

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Google's EmbeddingGemma 2 is an embedding model. We turned it into a speech-to-text model: an hour of audio in about 13 seconds on a base MacBook Air, entirely on device.

Download for Mac (free) v1.6 · macOS 14+ · Apple Silicon models download on first launch (715 MB)

Can an embedding model transcribe speech?

EmbeddingGemma 2 is a multimodal embedding model: text, images, audio and video in one shared space. Say a word out loud and its audio lands close to the written word.

So we tried reading words straight out of that space.

How it works

  1. EmbeddingGemma 2's audio encoder stays exactly as it is.
  2. A small reader moves each short slice of audio into the model's text space.
  3. The closest of ~229,000 English words wins, and the slices become a transcript.
  4. A tiny extra model adds punctuation and capitals.

Only the reader is trained: under two hours on 8×H100, on openly licensed English speech. The base model was never trained for speech-to-text.

How fast?

ModelRuns onMacSpeed
Embedding Gemma TranscribeNeural Enginebase M3 MacBook Air, 8 GB288×1 hour in 12.6 s
IBM Granite Speech 5.0 TurboCTCGPU (MLX)base M3 MacBook Air, 8 GB~150×1 hour in 25.7 s
NVIDIA Parakeet TDT 0.6B v3 (FluidAudio)Neural EngineM4 Pro156×
NVIDIA Parakeet TDT 0.6B v3 (FluidAudio)Neural EngineM5 Pro335×
Phonon-2, a Parakeet v3 fine-tune (FluidAudio)Neural EngineM5 Pro480×

× real time: seconds of audio per second of processing. Rows 1–2: our tests on the same base M3 MacBook Air. Rows 3–5: FluidAudio's published benchmarks on larger, newer Macs and different audio. A rough guide, not a like-for-like ranking.

Where it stands

Its word error rate is about 5% right now, against 2–3% for leading speech models. We believe a better-trained reader can close that gap; that's the next iteration.

Use it

Drop in an audio file, or hold Right Option, speak and release to dictate into any app. It runs on the Mac's Neural Engine; your audio never leaves the machine.