LinkedIn Videos API thumbnail: pick a still from the clip first

LinkedIn's Videos API page says "If the partner doesn't upload a thumbnail, a system generated thumbnail may be added to the video." To choose the frame yourself, pull stills with Sume's POST /v1/video-frames at the times you name, then upload the one you pick in your own LinkedIn call.

What does the Videos API say about thumbnails?

The quoted line is the only thumbnail rule used here: skip the upload and LinkedIn may generate one. The page's thumbnail upload sample sends a .jpg file.

How do I pick a good still?

Name several instants (1 to 24 in at[]), review the returned frames[].url values, then upload the winner. A frame is exact footage, so the thumbnail matches the video.

curl -X POST https://api.sume.com/v1/video-frames \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: li-thumb-001" \
  -d '{
    "video_url": "https://media.sume.com/artifacts/artf_demo/talk.mp4",
    "at": [1, 5, 10],
    "format": "jpeg"
  }'

Which format and size does LinkedIn want?

The page's sample uploads a .jpg, but the text quoted here does not state accepted formats or dimensions, so none are claimed. Use jpeg to match the sample, and check LinkedIn's current documentation for size rules.

What are the limits?

Frames come from sources of 300 seconds or less, and the route is unbilled. A long source needs a cut with https://docs.sume.com/models/video-trim first. A frame whose extract failed comes back with url null without failing the job, so check each entry. Sume does not upload to LinkedIn.

• Choose the still before you start the LinkedIn upload.
• Keep the artifact id next to the LinkedIn video id.
• Re-read LinkedIn's page before shipping.