LinkedIn 30-minute video: build 1800 s with Timeline

Timeline 1.0 takes audio.duration_seconds from 1 to 1800, which is exactly the 30 minutes LinkedIn's Videos API page lists ("Length: Three seconds to 30 minutes"). A single trim tops out at 900 seconds of output, so a 30-minute video is a Timeline job.

How do the two ceilings line up?

LinkedIn's upper length equals Sume's Timeline audio maximum, so there is no headroom: 1800 seconds is the cap on both sides.

What does a 30-minute render cost?

Timeline is priced at $0.10 per ceil(output minute), with a reserve of ceil(audio.duration_seconds / 60) minutes. For 1800 seconds that is 30 minutes, or $3.00. The plan route, POST /v1/timeline-1.0/plan, is unbilled and returns billable_minutes and estimated_cost_usd_micros first.

curl -X POST https://api.sume.com/v1/timeline-1.0/plan \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "audio": { "url": "https://media.sume.com/artifacts/artf_demo/talk.wav", "duration_seconds": 1800 },
    "video": [
      { "source_url": "https://media.sume.com/artifacts/artf_demo/part1.mp4", "start": 0, "duration": 900 },
      { "source_url": "https://media.sume.com/artifacts/artf_demo/part2.mp4", "start": 900, "duration": 900 }
    ]
  }'

What must the slots satisfy?

video[0].start must be 0, later starts must increase, and coverage may trail the spine by at most 0.5 seconds. Mind the render strategy: single is refused above 12 slots, and auto chunks past 12 segments.

What else should I check?

Keep the finished MP4 under LinkedIn's file size line (the same page lists 500MB), which Sume does not state or control. See LinkedIn's 500MB or 5GB for that discrepancy.

Why not just trim a 30-minute source?

Trim's source can be up to 1800 seconds, but its output is capped at 900, so trim alone can cut half of a 30-minute file at most. Use trim to prepare parts, for example two 900 second pieces, and Timeline to join them with an audio spine. Both are worker ffmpeg jobs with no model inference, and both need media.sume.com sources imported first.

• Trim: source up to 1800 s, output 0.2 to 900 s, $0.02 per job.
• Timeline: spine 1 to 1800 s, up to 200 slots, $0.10 per output minute.
• Import sources first with POST /v1/media-imports.