TikTok Spark Ads have no duration limit; Timeline stops at 30 minutes

TikTok's video ad specification page (read 2026-10-08) lists mp4 and mov for Spark Ads with no duration restriction, while non-Spark ads stop at 10 minutes. Sume's Timeline 1.0 does have a limit: audio.duration_seconds is 1 to 1,800, so the longest single render is 30 minutes. At $0.10 for each ceil output minute, a 30-minute render costs $3.00. Past 30 minutes, you cannot render the file in one Timeline job.

The price ladder

The cost is ceil(duration / 60) x $0.10. The job uses no provider inference, only worker ffmpeg, so there is no other charge in the render.

What the page does not say

The Spark Ads line on the TikTok page is about duration only. It does not say that a long Spark Ad is a good idea, that every other spec (size, bitrate, ratio) is lifted, or that an ad can be of any size. This post uses it only for the length. Check the other items you need on the page, such as 540x960 as the minimum for 9:16 non-Spark ads, before you assume a long file passes.

• Output is an MP4, which is on the Spark Ads format list.
• Timeline's default canvas is 1080x1920; set output.width and output.height for another size.
• The size of a long file grows with its length: a 30-minute file at 516 kbps is at least 116 MB (516 x 1,800 / 8 = 116,100 kB).

Why the cost is not the problem

At $3.00 for the longest possible render, the Timeline fee is small. The cost that grows with length is the content you put in the slots: a 30-minute video needs at least 30 minutes of footage or stills, and each generated clip is billed by its own model. A 30-second Seedance 2.5 clip at 720p and 9:16 costs $17.34, so even a few of them are much more than the render fee. Use stills or recorded video for long files if the budget is tight.

Planning a long render

Use the unbilled plan route to learn the cost before you start. It returns billable_minutes and estimated_cost_usd_micros, so a 1,800-second program should show 30 and 3,000,000 micros. A long render with many slots uses the chunked strategy automatically (auto chunks past 12 segments), and a program may have up to 200 slots. For 30 minutes and 200 slots, the average slot is 9 seconds (1,800 / 200).

If your source is a longer recording, video trim takes sources of up to 1,800 seconds and gives up to 900 seconds of output for $0.02, so a 25-minute recording can be trimmed before it goes into a render.