Tape Video Processing Setup#

Overview#

Tapes are converted from ZIP (frames + audio) to MP4 using Netlify Background Functions.

Duration Limit#

• Maximum tape duration: 30 seconds
• Client should check metadata.totalDuration before allowing POST
• Server validates and returns error if exceeded

Architecture#

Upload Flow#

1. Client uploads ZIP to DigitalOcean Spaces
2. Client POSTs to /api/track-tape with metadata
3. Server validates duration (max 30s)
4. Server creates MongoDB record
5. Server invokes background function (fire-and-forget)
6. Client receives response immediately

Background Processing#

1. Background function runs (up to 15 minutes)
2. Downloads ZIP from Spaces
3. Converts to MP4 using ffmpeg
4. Uploads MP4 back to Spaces
5. Syncs to ATProto (if user has account)
6. Updates MongoDB with status

Installation#

cd system
npm install @ffmpeg-installer/ffmpeg

Configuration#

netlify.toml#

Background function is configured with:

• External modules: @aws-sdk/client-s3, @atproto/api, adm-zip, @ffmpeg-installer/ffmpeg
• Included backend files
• Required environment variables

Environment Variables#

• ART_KEY / DO_SPACES_KEY - DigitalOcean Spaces access key
• ART_SECRET / DO_SPACES_SECRET - DigitalOcean Spaces secret
• MONGODB_CONNECTION_STRING - MongoDB connection
• PDS_URL - ATProto PDS URL

Client-Side Duration Check#

Add to tape upload UI:

// Before showing "Post to ATProto" button
const MAX_DURATION = 30; // seconds
const duration = tapeMetadata.totalDuration;

if (duration > MAX_DURATION) {
  // Hide Post button or show warning
  console.log(`Tape too long: ${duration}s (max ${MAX_DURATION}s)`);
  return;
}

// Show Post button

Retry Failed Conversions#

If background function fails, tapes can be reprocessed:

cd system/backend
node sync-atproto.mjs live --tapes-only --anonymous-only

Monitoring#

Check tape conversion status in MongoDB:

• mp4Status: "pending" | "processing" | "complete" | "failed"
• mp4StartedAt: When conversion started
• mp4CompletedAt: When conversion completed
• mp4Error: Error message if failed
• mp4: URL to MP4 file
• atproto.rkey: ATProto record key (if synced)