App Store preview poster frame defaults to second 5: check it

Plan what is on screen at second 5. Apple's specification page says the default poster frame of an app preview is taken at 5 seconds, and that previews appear before the screenshots on your product page. So the first thing a visitor sees may be that single frame. You can check it in advance by pulling frames at 0 and 5 seconds with Sume video frames.

What does Apple's page say?

Apple lists these values for app previews. Everything in the table is Apple's wording, not Sume's.

How do I see the poster frame?

Import the finished MP4 to Sume, then call video frames with at: [0, 5]. The route returns 202; poll GET /v1/video-frames/{id} until resource_status is ready. Each frame is a durable image with t, url, width and height. Leave out max_edge to keep the source size, or set it between 16 and 2160.

The source clip must be 300 seconds or shorter, which any app preview is. The job is billed by its Modal compute, not at a flat rate.

curl -X POST https://api.sume.com/v1/video-frames \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: preview-poster-check-1" \
  -d '{
    "video_url": "https://media.sume.com/artifacts/artf_demo/preview.mp4",
    "at": [0, 5],
    "format": "png"
  }'

What if second 5 is a loading screen?

Then re-edit so the best screen lands at 5 seconds. Trim a few seconds off the front with Video trim or move the loading section later. Check the new file the same way. Apple's page states the default only, so look in App Store Connect for whether you can choose a different frame, and use that if it is offered.

What is a sensible order of work?

Do the cheap checks first, so that you pay for as few renders as possible.

• Export the finished MP4 and import it with POST /v1/media-imports.
• Pull frames at 0 and 5 seconds and look at both.
• If the poster frame is weak, trim or re-order the footage, then pull the frames again.
• Probe the final file for duration, frame rate and audio before you upload it.
• Keep the reviewed file and its job id together, so you can see later what was checked.