How do I transcode uploaded videos into multiple formats with an API?

A common pattern is:

1. Upload the source video
2. Create a transcode job specifying output formats/resolutions/codecs
3. Process asynchronously in a worker/queue
4. Store outputs in object storage/CDN
5. Report job status back through polling or webhooks

Typical API flow

1) Upload

POST /videos
Content-Type: multipart/form-data

Response:

{
  "videoId": "vid_123",
  "uploadUrl": "https://storage.example.com/...",
  "status": "uploaded"
}

2) Start transcoding

POST /videos/vid_123/transcode
Content-Type: application/json

Example body:

{
  "outputs": [
    { "format": "mp4", "resolution": "1080p", "videoCodec": "h264", "audioCodec": "aac" },
    { "format": "mp4", "resolution": "720p",  "videoCodec": "h264", "audioCodec": "aac" },
    { "format": "webm", "resolution": "720p", "videoCodec": "vp9",  "audioCodec": "opus" }
  ]
}

Response:

{
  "jobId": "job_456",
  "status": "queued"
}

3) Check status

GET /transcode-jobs/job_456

Response:

{
  "jobId": "job_456",
  "status": "processing",
  "progress": 65,
  "outputs": [
    { "format": "mp4", "resolution": "1080p", "url": null },
    { "format": "mp4", "resolution": "720p",  "url": null },
    { "format": "webm", "resolution": "720p", "url": null }
  ]
}

When finished:

{
  "jobId": "job_456",
  "status": "completed",
  "progress": 100,
  "outputs": [
    { "format": "mp4", "resolution": "1080p", "url": "https://cdn.example.com/vid_123_1080p.mp4" },
    { "format": "mp4", "resolution": "720p",  "url": "https://cdn.example.com/vid_123_720p.mp4" },
    { "format": "webm", "resolution": "720p", "url": "https://cdn.example.com/vid_123_720p.webm" }
  ]
}

Backend implementation ideas

Option A: Use FFmpeg in your own workers

• API receives job request
• Save job to DB/queue
• Worker pulls job
• Runs ffmpeg to generate each output
• Uploads files to S3/GCS/Azure Blob
• Updates job status

Example FFmpeg commands:

ffmpeg -i input.mp4 -c:v libx264 -preset medium -b:v 5M -c:a aac output_1080p.mp4
ffmpeg -i input.mp4 -c:v libx264 -preset medium -b:v 3M -c:a aac output_720p.mp4
ffmpeg -i input.mp4 -c:v libvpx-vp9 -c:a libopus output_720p.webm

Option B: Use a managed video API

If you don’t want to manage encoding infrastructure, use a service like:

• AWS Elemental MediaConvert
• Mux
• Cloudflare Stream
• Bitmovin
• Zencoder

These usually provide:

• Upload URLs
• Transcode presets
• Webhooks for completion
• CDN delivery

Recommended API features

• Asynchronous jobs (don’t block the request)
• Presets instead of raw FFmpeg settings for easier client use
• Webhooks for completion/failure notifications
• Idempotency keys to avoid duplicate jobs
• Retry logic for transient failures
• Signed URLs for secure uploads/downloads
• Rate limiting and validation of supported outputs

Minimal endpoint design

• POST /videos → create video record / upload URL
• POST /videos/{id}/transcode → start job
• GET /transcode-jobs/{id} → status
• POST /webhooks/video-transcode → receive completion callback

If you want, I can sketch a complete example in Node.js, Python/FastAPI, or Go with FFmpeg and a job queue.