Reels ads: sound strongly recommended, captions optional; 12 for $2.40

What Meta says about sound and captions

Meta's ad-guide pages (read 2026-10-09) treat sound and captions as optional on all three video placements, with different emphasis. On the Instagram Reels page, captions are "optional, but recommended" and sound is "optional, but strongly recommended". On Instagram Feed, captions are optional but recommended and sound is optional but recommended. On Facebook Feed, both are optional but recommended. None of them is a rejection condition.

What that means for how you build the ad

Because sound is optional, a Reels ad that only works with audio on is a creative risk, not a policy problem. The practical answer is to make the ad understandable with the words on screen and enhanced by audio. Burned-in captions do that without relying on platform caption tools. Meta's Reels page also says to keep at least 14% of the top, 35% of the bottom and 6% of each side free of text and logos, so captions have to sit in the middle band.

The caption job on Sume

The video captions docs describe POST /v1/video-captions: it takes a public HTTPS video URL and burns captions with a style, an optional language hint and an optional script_text to align wording to a known script. The docs state a fixed reservation of $0.20 per accepted job for videos of up to 60 seconds. A 30-second ad is therefore $0.20, and 12 of them are 12 x $0.20 = $2.40. The standalone caption route is not in the live public catalog list I read on 2026-10-08, so confirm the price with your own estimate before you queue a batch.

• Speech clips: let recognition time the words, and pass script_text when you have the approved copy so the wording matches.
• Silent clips: the job fails with caption_no_speech and the docs point to cues or segments with text, start and end.
• Restyle: send source_caption_id instead of video_url to re-burn with a different style without a second speech-recognition pass; the docs say the price does not change.

Placement inside the Reels frame

The default style resolves to slam for Latin text, and black-outline places Korean captions in the middle of the frame. design.placement.anchor_ratio sets the center of the caption line as a fraction of frame height, so you can move it. With Meta's numbers, the usable vertical band runs from 14% of the height down to 65% (100% minus 35%), so keep the anchor and the half-height of the line inside it, then check the result on a phone.

Re-checking is cheap in one respect only: a restyle is a fresh render at the same $0.20 under the docs, so plan the number of attempts into the batch cost.