Reels safe zone overlays in Canva or Adobe Express vs Sume captions

Meta's Reels ads page names Canva and Adobe Express as places to use safe-zone overlays while you design. Sume burns captions into a video, so the matching control is the caption design.placement.anchor_ratio, a fraction of frame height. Check one rendered still against Meta's overlay before you run a batch.

What Meta's page says

"Instagram & Facebook Reels: Create Short Video Ads" (read 2026-10-05) recommends 9:16 vertical video and offers a Reels safe zone checker in PowerPoint, Photoshop and Keynote formats. It also names Canva and Adobe Express for safe-zone overlays and suggests working with creators for native 9:16 content. No numeric margins are given in the text I read, so use Meta's own overlay.

Where Sume's control sits

The video captions docs describe a design.placement group with anchor_ratio and landscape_anchor_ratio, both as a fraction of frame height. Raise or lower the value to move the caption line. The punch and tiktok-green styles do not support design, so pick a style that does when you need control.

Caption width is a similar knob: typography.safe_width_ratio limits how wide a line can run, which helps keep text away from the sides.

{
  "video_url": "https://media.sume.com/artifacts/artf_demo/reel.mp4",
  "style": "slam",
  "cues": [{ "text": "Free returns", "start": 0.5, "end": 3 }],
  "design": {
    "placement": { "anchor_ratio": 0.62 },
    "typography": { "safe_width_ratio": 0.8 }
  }
}

A short loop

Render one clip, pull stills with video frames, lay them over the Canva or Adobe Express overlay, and adjust anchor_ratio. The source_caption_id field restyles an earlier caption job without a second speech-to-text pass, which makes tuning cheaper.

• Change one number at a time.
• Check the busiest caption, not the first.
• Keep the value in your batch config.

Boundaries

Sume does not render the Meta checker and does not read platform UI. The overlay stays in your design tool; Sume gives you the numbers to move text.