Transcribe speech to text in the browser. Based on a wasm build of whisper.cpp.

• Docs
• Example File Transcriber
• Example Stream Transcriber (experimental)

All packages are under @transcribe namespace.

Your webserver must serve the files with cross origin headers.

"Cross-Origin-Embedder-Policy": "require-corp"
"Cross-Origin-Opener-Policy": "same-origin"

You need a ggml model file to run Transcribe.js. You can download them on hugging face https://huggingface.co/ggerganov/whisper.cpp/tree/main . You should start with the (quantized) tiny or base models. Larger models propably won't work but you can try it, though.

Install shout wasm and transcriber packages

npm install --save @transcribe/transcriber

copy the shout.wasm and webworker files to your project directory

# copy shout wasm
cp node_modules/@transcribe/shout/src/shout/shout.wasm.worker.mjs /your/project
cp node_modules/@transcribe/shout/src/shout/shout.wasm.js /your/project

# copy audio-worklets, only needed if you want to use StreamTranscriber
cp -r node_modules/@transcribe/transcriber/src/audio-worklets /your/project

You can use Transcribe.js without a bundler or package manager. Download the files from this repository, copy the src/* directories to your webserver and include the following into your HTML. Make sure to set the correct paths in the import map.

<!-- set paths to js files -->
<script type="importmap">
  {
    "imports": {
      "@transcribe/shout": "/src/shout/shout.wasm.js",
      "@transcribe/transcriber": "/src/index.js"
    }
  }
</script>

<!-- use type="module" for es6 imports -->
<script type="module">
  import { FileTranscriber } from "@transcribe/transcriber";

  ...
</script>

For full code examples and advanced usage see https://www.transcribejs.dev or check out the File Transcriber Example.

import { FileTranscriber } from "@transcribe/transcriber";

// create new instance
const transcriber = new FileTranscriber({
  model: "/your/project/ggml-tiny-q5_1.bin", // path to ggml model file
  workerPath: "/your/project", // directory of shout.wasm.worker.mjs copied before
});

// init wasm transcriber worker
await transcriber.init();

// transcribe audio/video file
const result = await transcriber.transcribe("/your/project/my.mp3");

console.log(result);

The result is an JSON object containg the text segements and timestamps.

{
  "result": {
    "language": "en"
  },
  "transcription": [
    {
      "timestamps": {
        "from": "00:00:00,000",
        "to": "00:00:11,000"
      },
      "offsets": {
        "from": 0,
        "to": 11000
      },
      "text": " And so my fellow Americans ask not what your country can do for you, ask what you can do for your country.",
      "tokens": [
        {
          "text": " And",
          "timestamps": {
            "from": "00:00:00,320",
            "to": "00:00:00,350"
          },
          "offsets": {
            "from": 320,
            "to": 350
          },
          "id": 400,
          "p": 0.726615 // propability, aka. how likely the estimate is true, 0..1, 1 is best
        },
        // ... one token per word
      ]
    }
  ]
}

Clone the repository, install dependencies, start the dev server and open http://localhost:9876/examples/index.html in your browser.

git clone https://github/transcribejs/transcribe.js
cd transcribe
npm install
npm run dev

The library is not written in typescript. This way no extra build step is needed during development and in production.

To still get proper type support type definitions get generated from JSDoc comments.

npm run generate-types

The whisper.cpp repository is a git submodule. To get the latest version of whisper.cpp go into the directory and pull the latest changes from github.

cd shout.wasm/whisper.cpp
git pull origin master

The wasm files are build from shout.wasm/src/whisper.wasm.cpp. If you want to add new functions from whisper.cpp to the wasm build this is the file to add them.

I'm pretty sure that this will not compile on every machine/architecture, but I'm no expert in C++. If you know how to optimize the build process please let me know or create a pull request. Maybe this should be dockerized.?

# run cmake to build wasm
npm run wasm:build

# copy emscripten build files to project
npm run wasm:copy

Unit/functional tests for the Transcriber functions.

npm run test:unit

E2E tests using Playwright. Firefox somehow needs waaaaaay longer during e2e test than in a the "real" browser.

npm run test:e2e

or use the Playwright UI for details

npm run test:e2e-ui

Thank you to the creators and contributors of the following open source libraries that were used in this project:

• whisper.cpp: A C++ implementation of whisper. GitHub Repository
• emscripten: A toolchain for compiling C and C++ code to WebAssembly. Official Site
• water.css: A minimal CSS framework for styling HTML. Official Site
• fft.js: A library for Fast Fourier Transform calculations. GitHub Repository
• Moattar, Mohammad & Homayoonpoor, Mahdi. (2010). A simple but efficient real-time voice activity detection algorithm. Research Paper
• vitest: A website for testing voice recognition. Official Site
• Playwright: A tool for automating browser testing. Official Site

• examples/albert.ogg Radio Universidad Nacional de La Plata, CC BY-SA 3.0, via Wikimedia Commons
• examples/jfk.wav: CC BY-SA 3.0, via Wikimedia Commons