TikTok 516 kbps floor: 0.033 bits per pixel at 540x960, 0.008 at 1080p

TikTok's floor of 516 kbps is a lower bound on the whole frame, not on quality. Spread over a 540x960 frame at 30 fps it is 516,000 / (518,400 x 30) = 0.033 bits per pixel per frame. Spread over a 1080x1920 frame it is 516,000 / (2,073,600 x 30) = 0.0083, four times thinner. The same number of bits describes a fourth of the detail per pixel at the larger size, so a bigger render does not become safer by passing the floor.

The figures are from TikTok's video ad specifications page (read 2026-10-09): non-Spark ads need 9:16 at 540x960 or more, 16:9 at 960x540 or more, or 1:1 at 640x640 or more, up to 10 minutes, 500 MB or less, with bitrate of 516 kbps or more.

The numbers

Pixels per frame, then bits per pixel at exactly 516 kbps and 30 fps. These are bounds, not targets: real files are usually larger.

What this means for the render size

The page gives only minimum dimensions, so any size at or above the minimum passes. Sume's timeline and video trim output take even width and height from 256 to 2160, so every row above is available. The practical choice is the smallest frame that looks sharp on a phone, because a smaller frame gets more bits per pixel from any given bitrate. For text-heavy ads, 720x1280 is a common compromise and sits at roughly 0.019 bits per pixel at the floor.

Sume has no bitrate field. The trim and timeline APIs refuse codec, crf and ffmpeg keys, and the server picks the encoder settings. So you cannot raise the bitrate to improve a large frame. You can only choose the frame size, the frame rate (24, 25, 30 or 60) and the content.

Why not just pick the smallest frame

Because TikTok's page sets a minimum and nothing else on resolution, a 540x960 render passes, but it will look soft on a modern phone screen. The floor does not tell you the sweet spot. A reasonable test is to render the same 15-second ad at 540x960 and 720x1280 and compare stills at the same timestamps with video frames. Both renders cost the same on Sume: a Timeline render is billed per output minute, not per pixel, so each is $0.10 for a clip of one minute or less.

That last point is the real lever. Sume's price does not change with frame size inside the allowed range, so the choice is about delivery, not cost. Larger frames make larger files; TikTok's file cap is 500 MB, and at a 10-minute length that cap is the next constraint to check.

Check the delivered file

The 516 kbps line is about the average bitrate of the whole file, which is file size in bits divided by duration. A 30 second ad needs at least 516 x 30 / 8 = 1,935 KB. Compute it from the downloaded file's size and the duration_seconds in the job result; the Sume docs do not state the encoder's bitrate. Do the check before upload, since TikTok's page is the authority on whether an ad passes.

Prices for the prep are small: a Timeline render is $0.10 per output minute, rounded up, and a video trim with an output conform is $0.02 per job.