Pinterest video Pin 400: the cover image is required, here is a frame

A Pinterest video Pin cannot be created without a cover image: the docs say to provide a video and a cover image, and a valid image URL is required to avoid a 400 Bad Request. Extract a still from your Sume avatar clip with the unbilled video-frames route and pass its public URL as cover_image_url.

What are the four steps for a video Pin?

Pinterest's create-Pins guide lists four steps. Register your intent with the media create endpoint, upload the video with a multipart POST to the returned upload_url, confirm with the media get endpoint until the status reads succeeded, and call pins create with source_type: video_id, the cover_image_url and the media_id. Supported video formats on that page are .mp4, .mov and .m4v. The guide gives no file size, length or codec numbers, so I will not quote any.

How do you get a cover image from a Sume clip?

Video frames takes one media.sume.com clip and either at[] or fps, then returns durable image artifacts at source size. It is unbilled, submit is always 202, and format defaults to jpeg. Ask for a time where the avatar looks at the camera, and read the URL from the finished resource.

curl -X POST https://api.sume.com/v1/video-frames \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: pin-cover-001" \
  -d '{
    "video_url": "https://media.sume.com/artifacts/artf_demo/talk.mp4",
    "at": [1.5]
  }'

Can you use the avatar preview still instead?

An Avatar video preview returns preview_image_url, the first-frame still, before the full render. It is never caption-burned, which is good for a cover. But it is a pre-render still, and the final video may differ slightly, so for a cover that matches the played clip pick a frame from the finished video.

Processing time and the creative_type quirk

Pinterest notes that video Pins may need extra processing time after creation. While this normally takes a few seconds, you can see a wrong creative_type until it finishes. Do not treat that as a failure; read the Pin again after a short wait before you act on it.

What Sume does not do

Sume does not upload to Pinterest in the docs I read, and I could not fetch Pinterest's media endpoint reference pages, so I have not quoted its status values beyond the succeeded state named in the guide. Pin ratio rules for images are covered in the Pin specs post.