How do I make one intro bumper and reuse it in every course lesson?

Make the bumper once, keep the file, and add it to each lesson with a render. The bumper is a title card image ($0.075 at medium on ideogram/ideogram-v4.5), animated for 5 seconds ($0.63 at 720p on gemini-omni-flash-1.1), plus a music sting ($0.125): $0.83 in total, one time. Each lesson then costs $0.01 to detach its audio, $0.01 to join the sting and the lesson audio, and $0.10 per started minute to render. For an 8-minute lesson that is $0.82, and for 24 lessons the course comes to $20.51.

Make the bumper once. Every generation is a new random result, so a bumper regenerated per lesson looks different each time, and a branded intro that changes is not branding.

Design the bumper for reuse

A good bumper is 3 to 5 seconds, carries the course name and the colours, and has no speech. Leave the module number out of the animated clip and burn it in later with caption cues if you want one per module. Then one clip serves every module, and only the text changes.

Pick the aspect ratio of your lessons first. Omni takes 16:9 or 9:16, so make a 16:9 bumper for landscape lessons and a 9:16 one if you teach on a phone.

curl -X POST https://api.sume.com/v1/videos \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: course-bumper-v1" \
  -d '{
    "model": "gemini-omni-flash-1.1",
    "prompt": "Slow light sweep across the title card, subtle grain, no camera shake",
    "duration": 5,
    "resolution": "720p",
    "aspect_ratio": "16:9",
    "generate_audio": false,
    "frame_images": [{ "type": "image_url",
      "image_url": { "url": "https://media.sume.com/artifacts/artf_demo/titlecard.png" },
      "frame_type": "first_frame" }]
  }'

Why each lesson needs a join

A Timeline 1.0 render needs one audio spine for its whole length, and a silent bumper has no audio. The fix is to make the spine yourself. Detach the lesson's audio from its video with POST /v1/audio-detach ($0.01, source up to 1,800 seconds). Then call Timeline audio with operation: concat and two parts: the sting, cut to 5 seconds with duration: 5, and the lesson audio. The result returns segments[] with each part's offset, and that is the audio for the render.

In the render, the bumper is the first video[] slot (start 0, duration 5) and the lesson recording is the second (start 5). Check warnings[] on the result.

curl -X POST https://api.sume.com/v1/timeline-1.0/audio \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: lesson-07-spine" \
  -d '{
    "operation": "concat",
    "parts": [
      { "url": "https://media.sume.com/artifacts/artf_demo/sting.wav", "duration": 5 },
      { "url": "https://media.sume.com/artifacts/artf_demo/lesson07.wav" }
    ]
  }'

The minute boundary

Timeline 1.0 bills $0.10 per started output minute. A lesson of 7 minutes 30 seconds plus the 5-second bumper is 7:35, which is 8 started minutes, $0.80. A lesson of exactly 8:00 plus the bumper is 8:05, which is 9 started minutes, $0.90. Check each lesson's length: if one is a few seconds over a minute boundary, trimming a second of silence at the start saves ten cents.

That is the only real extra cost of reuse. The bumper is a file, and adding it to a render is not a new generation.

What the course costs

• The render is the main cost, and it would be there without a bumper if you re-export every lesson anyway.
• A new season with a new bumper costs $0.83 and leaves the old lessons alone.
• Burn module numbers with caption cues at $0.20 per lesson if you want them.