Square TikTok ad from an avatar video: 1:1 at 720p vs 640 px minimum

TikTok's In-Feed page lists 640 by 640 as the minimum for square non-Spark video. Sume's avatar video supports aspect_ratio of 1:1 and renders at 720p, so a square take is above that minimum. TikTok recommends 9:16, so test the square against a vertical version before you commit budget.

What TikTok's page says

On "TikTok Auction In-Feed Ads" (read 2026-10-05), non-Spark sizes are vertical 9:16 at 540 by 960 or more (recommended), horizontal 16:9 at 960 by 540 or more, and square 1:1 at 640 by 640 or more.

What avatar video offers

Per the avatar video docs, aspect_ratio accepts 1:1, 3:4, 9:16 (the default), 4:3 and 16:9. The output is 720p only, and the duration is 4 to 60 seconds. A 1:1 frame at 720p is 720 by 720, assuming the output matches the stated 720p on its short side; confirm with video inspect.

curl -s https://api.sume.com/v1/catalog \
  -H "Authorization: Bearer $SUME_API_KEY" | head -c 600

Square or vertical

TikTok marks vertical as the recommended shape on that page. A square gives less height to work with, so a caption line and a face compete for space. If you run both, render both and keep the winner.

• Ask for 1:1 for the square test and 9:16 for the control.
• Keep the script the same for a fair comparison.
• Check size, length and bitrate against the page before upload.

Captions

Burn captions after the avatar render with video captions. The docs say inline captions on avatar video are rejected above 60 seconds of estimated length, so keep the take short or caption in a second pass.