Add burned-in captions to new Google Drive videos with Shotstack

Quick overview

This workflow watches a Google Drive folder for new video files, shares each file via a public link, then uses Shotstack to auto-transcribe and burn captions into the video and saves the captioned MP4 back to Google Drive.

How it works

1. Triggers when a new video file is created in a specified Google Drive folder.
2. Updates the new file’s sharing settings in Google Drive so Shotstack can download it via a public link.
3. Sends the Google Drive download URL to Shotstack to render a new MP4 with burned-in captions generated from the video’s speech.
4. Polls Shotstack every 10 seconds to check the render status until it is done or failed.
5. If the render fails, stops the workflow and returns Shotstack’s error message.
6. If the render succeeds, retrieves the rendered asset URL from Shotstack, downloads the captioned video, and uploads it to Google Drive as a new “(captioned)” copy.

Setup

1. Connect your Google Drive credentials and select the folder to watch for new videos.
2. Connect your Shotstack credentials (API key) and confirm your Shotstack project can create renders.
3. Set the destination Google Drive folder for the captioned output so it is not the same as the watched folder (to avoid retrigger loops).

Requirements

• A Shotstack account and API key
• The video must contain speech. Shotstack transcribes the audio, and a clip with no spoken audio fails the render.
• Very large Google Drive files return a scan warning page instead of the video. Host those elsewhere.

Customization

• Restyle the subtitles with the caption asset's font, background and margin options.
• Change the output resolution or aspect ratio in the output block.
• Replace the last two nodes to send the finished video somewhere other than Google Drive.