Facebook feed video ad minimum is 120 px; Sume's smallest is 256

The smallest video Meta's Facebook feed spec accepts is 120 pixels on each side, and the smallest video Sume Timeline 1.0 can render is 256 by 256. The Sume floor sits above the Meta floor, so a Timeline render can never be rejected for being too small. The practical limit is the other direction: the page recommends 1440 x 1800, and Timeline stops at 2160 on any edge.

Both numbers come from each side's own page, read on 2026-10-07. The Facebook figures are from Meta's Facebook feed video ad guide. The Sume figures are from the Timeline 1.0 docs.

Side by side

What the minimum means for a render

A 120 px minimum matters for people who export thumbnails or small preview loops by hand. If you ask Timeline for output.width and output.height, the allowed values are even integers from 256 to 2160, so a size below 256 is outside the documented range. Anything you pick above that floor clears Meta's 120 px check.

The recommended 1440 x 1800 canvas is inside the Sume range, so the same request that makes a 1080x1350 draft makes the final. Timeline bills $0.10 per output minute, rounded up, so a 20-second ad costs the same at either size. Confirm the live rate in the catalog before budgeting.

What Sume does not do

Sume does not state a maximum output file size in the Timeline docs, so the 4GB cap on the Facebook page is something you check on the file you download, not something Sume promises. Sume also does not render 4:5 by name: you give a width and height such as 1440 by 1800, and the clip placed in each slot follows the slot's fit mode (cover, contain, stretch or blur).

Length is the other gap. Meta lists up to 241 minutes; one Timeline render stops at 30 minutes. For ads this long is rarely a constraint, but it is a real difference.

Finally, Sume does not submit anything to Meta. You upload the MP4 in Ads Manager and check the page again, because Meta can change a spec without notice.