Captions covering Shorts stickers: move the line with anchor_ratio

Burned-in captions and Shorts stickers share the same pixels, and stickers are added after you import the file, so the captions are already baked in. On Sume you can move the caption line before you burn it: send design.placement.anchor_ratio on a standalone caption job, the line's centre as a fraction of frame height, accepted from 0.05 to 0.95. Re-burn with a different value if the sticker goes where the words are.

The YouTube side comes from Enhance your Shorts and Tag products in your content, read on 2026-10-03. The caption side comes from the video captions doc; the 0.05 to 0.95 bounds come from the caption renderer's validation in the repo.

Which stickers can land on the picture?

The Enhance your Shorts page lists Q&A, Quiz, Poll, Add yours, AI Sticker, Image Sticker and a Shopping Product sticker, and says a timeline editor handles video, text, stickers, music and voiceover. YouTube Help adds that the Shopping product sticker is in the bottom-left corner by default and its size and placement can be changed in the mobile app. Other stickers are placed by the creator, so you cannot know in advance where they will end up.

• Shopping product sticker: bottom-left by default.
• Quiz: up to 2 answer options.
• Poll: 2 voting options.
• Q&A, Add yours, AI Sticker, Image Sticker: placed by the creator.

How do I move the caption line?

Caption styles are sets of design tokens, and design overrides them for one request. The placement group has two fields: anchor_ratio, the line centre as a fraction of frame height, and landscape_anchor_ratio. A value of 0.3 puts the line in the upper third; 0.5 is the middle. design is not supported on the punch and tiktok-green styles, so use slam (the default for Latin speech) or one of the other styles.

Numbers outside the documented range are a 400, so the failure comes at request time, not after a billed render.

curl -X POST https://api.sume.com/v1/video-captions \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: captions-high-001" \
  -d '{
    "video_url": "https://media.sume.com/artifacts/artf_demo/clean.mp4",
    "style": "slam",
    "design": { "placement": { "anchor_ratio": 0.3 } }
  }'

Can I try a second position without paying for speech-to-text again?

Yes. Pass source_caption_id instead of video_url and Sume reuses the caption's source video and the word timings it already has. The restyle is still a render, so billing is unchanged: a standalone caption job is $0.20 for videos up to 60 seconds under the current fixed estimate, and you should confirm live in GET /v1/catalog.

Burn captions on the clean version, not on a clip that already carries burned-in words. The docs say the clip should be a fetchable public HTTPS URL, and signed or private URLs are rejected.

What is a safe default?

There is no universal safe zone from these sources, so pick a rule for your series and keep it. A reasonable approach is to move the caption line away from the sticker you plan to use, and put the sticker where the picture is quiet.

What Sume does not do

Sume cannot see where you will drag a sticker and does not read YouTube's editor state. It places a caption line where you tell it to and returns a file. Check the result at phone size before you import it.