Transcriber

A fast, Rust video subtitle pipeline that:

• Extracts audio from a video using ffmpeg
• Transcribes speech into text with precise timestamps using whisper_rs
• Generates styled karaoke-style ASS subtitles (with word-level highlighting)
• Burns subtitles into videos or overlays on new video, image, or solid color backgrounds with ffmpeg

Note

More examples are available in the example directory. The following is just a GIF for visual demo purposes

Important

Tested on macOS only.

The instructions below assume you’re on a Mac (using Homebrew).

Engineering Requirements Document

The Engineering Requirements Document (ERD) is available here :

-> ERD on Google Docs

Getting started

1. Install ffmpeg

brew install ffmpeg

2. Build Transcriber

You can now build the transcriber using Rust Cargo.

cargo build

3. Run Transcriber

cargo run -- --input "example/input_audio.wav"

This runs the pipeline end-to-end:

• extracts or processes audio,
• transcribes with Whisper,
• generates subtitles,
• burns subtitles into a new video.

Configuration

In the style.json file, you control:

• Subtitle text styling: font, size, colors, alignment
• Background style: solid color, image, or looping video

You can control your background type to be either solid, video, or image. Here are the 3 way to configure it:

• Video Background

{
  "background": {
    "type": "video",
    "solid_color": null,
    "video_path": "assets/bg_example.mp4",
    "image_path": null
  }
}

• Image Background

{
  "background": {
    "type": "image",
    "solid_color": null,
    "video_path": null,
    "image_path": "assets/bg_image.jpg"
  }
}

• Solid Background

{
  "background": {
    "type": "solid",
    "solid_color": "#101020",
    "video_path": null,
    "image_path": null
  }
}

Note

You can find the example of each of those configurations in the example directory. In assets directory, you will find the video and image backgrounds used in those examples.