n8n Workflow: Captioned Vertical Video Clips from Google Drive

Turn long videos in Google Drive into vertical, captioned clip reels—automatically

This n8n workflow watches a specific Google Drive folder, then automatically extracts 9:16 vertical video clips with burned-in captions using CNAPS. Each resulting clip is saved back to Drive and logged in Google Sheets, with a Slack notification when clips are ready.

What this workflow does

• Triggers on new uploads: when a new video file is created in your chosen input Google Drive folder.
• Waits safely for processing: it calculates a processing wait time from the video’s Drive-reported duration, and prevents using the same folder for both input and output.
• Uploads the video to CNAPS: opens a CNAPS MCP session, requests a one-time upload URL, downloads the source video from Google Drive, and uploads it to CNAPS.
• Extracts and captions clips: starts a CNAPS clip-extraction run that reframes to 9:16 and burns in captions, then waits until processing completes.
• Processes CNAPS results: fetches the final list of subtitled clips, flattens them into one item per clip with titles and timecodes, and downloads each clip as an MP4.
• Saves + logs outputs: stores each clip in your configured Google Drive output folder and appends clip metadata plus the Drive link to a Google Sheets tab.
• Notifies via Slack: posts a summary of created clips, or an error message if CNAPS returns no clips.

Use cases

• Repurpose long-form recordings into short vertical social clips for daily posting.
• Automatically generate captioned excerpts for product demos stored in Google Drive.
• Maintain an auditable library of clip outputs with Drive links in Google Sheets.
• Get real-time Slack alerts for successful clip extraction runs.

Technical details

• Google Drive (trigger + download/source upload destination)
• Google Sheets (append clip metadata and Drive links)
• Slack (success/error notifications)
• CNAPS MCP client at https://mcp.cnaps.ai/mcp using header auth (x-api-key)
• Built with n8n nodes such as if, set, code, wait, slack, and sticky note