What YouTube's Shorts and TikTok's ad pages list, and what they omit
The two help pages I could read list limits unevenly: no codec on either, no file size on YouTube's. Meta and Instagram pages would not load.
Most spec posts present a tidy table with every cell filled. The vendors' own pages are patchier. YouTube's Shorts help page gives a length (up to 3 minutes) and a resolution ceiling (1080p) and no file size, format or frame rate. TikTok's ad specification page gives ratios, minimum sizes, length, file size, container formats and a bitrate floor, and names no codec. I tried Instagram's and Meta's help pages and they returned no readable article text, so this post states no Instagram or Meta numbers.
What each page says
This is what the pages returned when I read them on 2026-10-06. A fetch tool summarised the page text, so a blank means the text I received did not list the value, not that the platform has no rule.
| Attribute | YouTube Shorts | TikTok non-Spark ad |
|---|---|---|
| Orientation / ratio | Vertical, no ratio printed | 9:16 recommended; 16:9 and 1:1 also listed |
| Length | Up to 3 minutes | Up to 10 minutes |
| Resolution | 1080p maximum | Minimums: 540x960, 960x540, 640x640 |
| File size | Not listed | 500 MB or less |
| Formats | Not listed | .mp4, .mov, .mpeg, .3gp, .avi |
| Bitrate | Not listed | 516 kbps or more |
| Codec | Not listed | Not specified |
What this means for AI video
Three things follow. First, the things you can set in a Sume request line up with the things the pages state: ratio, resolution and length. Second, the things the pages are quiet about, codec and frame rate, are things Sume's Timeline does not let you set anyway; it rejects codec and crf keys. Third, a gap on a page is a reason to test one upload, not a licence to assume.
The 4:5 or 9:16 post compares ratios across more ad platforms.
How these pages were read
The method was simple: fetch each help page and ask for the exact figures. For YouTube, the Shorts page returned the 3-minute length and 1080p ceiling, and said nothing about file size or format. For TikTok, the ad specification page returned the table summarised above, and it described the safe zone as depending on ratio, caption length and format, with downloadable files.
Pages for Instagram Reels and for Meta ads did not return article text when fetched, only a page title or a help-centre header. I did not fall back on third-party guides, since a competitor's numbers belong to the competitor. If you need those platforms, open their help centres in a browser and read the current values yourself.
That leaves a real hole in this series, and it is better stated than papered over. The Sume side, ratios, durations and the way to request them, is the same whichever platform you target.
How to fill the gaps
Upload one finished file to the real platform before you batch fifty. Keep the clean master. And re-read the page on the day you ship, because specs move: the Spark row on TikTok's page is a good example of a row that is mostly blanks today and could fill in. Sume's own limits are in the Videos and Timeline docs, and the catalog is the live answer.
Sources
Related posts
More in Use cases
- Where a YouTube Shorts series can appear: search, Shows tab and more
YouTube's help lists search, Recommended shows, Continue watching and a Shorts icon in the Shows tab. What each means for how you plan a series.
- Which Sume video model makes a 15-second 9:16 ad? A catalog filter
List the models in GET /v1/videos/models that accept 15 seconds at 9:16 with a short Python filter, instead of trusting a stale table.
- Who approves the render: AI copilot or agent for avatar videos?
Tavus says choose a copilot for irreversible actions. A paid avatar render cannot be undone, so the preview, dry run and spend cap decide who approves.
- Yard sign artwork via API: 3:2 art, a quoted headline, a print check
Generate yard sign artwork at 3:2 on Sume with GPT Image 2.5 or Ideogram 4.5, keep the headline to a few words, quote it, and check the pixel size for print.
Written by Sume