Is 4:5 allowed as a TikTok in-feed ad? The page lists three ratios

TikTok's in-feed specification page lists three aspect ratios for non-Spark ads: 9:16 (recommended, 540 x 960 minimum), 16:9 (960 x 540 minimum) and 1:1 (640 x 640 minimum). 4:5 is not on that list, so a 4:5 master made for Facebook's feed should be reshaped before upload. The page says nothing about ratios for Spark Ads, which only list the format and caption.

The three ratios

Option 1: a 9:16 canvas

Timeline 1.0 takes output.width 1080 and output.height 1920, with fit per slot: cover, contain, stretch or blur. A 4:5 clip on a 9:16 canvas under contain has bars above and below; under blur those areas show a blurred copy, and cover would crop the sides. Cover loses the most picture, so for a 4:5 master pick contain or blur.

Option 2: crop to 1:1

A video filter crop with width 1 and height 0.8 gives 1080x1080, which clears the 640 minimum. It removes 20 percent of the height, so check that captions or logos at the top and bottom survive. The job costs $0.02 and the check is free.

What Sume does not do

Sume does not reshape a video automatically for a platform and does not upload to TikTok Ads. The TikTok page lists the ratios for non-Spark ads only, so a Spark Ad has other constraints you need to read on that page before relying on this.

A quick decision rule: if the 4:5 master has important content in the top or bottom fifth, use the 9:16 canvas, because it keeps the whole frame. If the subject is centered and the edges are safe to lose, the 1:1 crop gives a larger subject. Either way the finished file should be checked against the TikTok page's size minimums, file size and bitrate.