Crop a 10-minute 16:9 ad to 9:16: filter stops at 300 s, so split

Sume video filter refuses a source longer than 300 seconds, and TikTok's non-Spark in-feed page (read 2026-10-08) allows ads of up to 10 minutes, so a 600 second landscape ad cannot go through one crop job. Split it with video trim into two 300 second halves, crop each half with video filter, and join them with Timeline. The cost is 2 x $0.02 for trims, 2 x $0.02 for crops and $1.00 for a 600 second Timeline, which is $1.08.

The limits that force the split

The filter limit is in the Sume docs (output_duration_exceeded for a longer source). The trim source limit is 1800 seconds, so a 600 second file is fine there.

The steps and the bill

Trim A is start 0, duration 300. Trim B is start 300, duration 300. Crop both with the same op so the join has no jump: for a centered 9:16 crop of 1920x1080, x is 0.3418, width 0.3164 and height 1. Then render a Timeline with the two crops as slots at start 0 and start 300, with the original audio as the spine at 600 seconds.

A shorter route when you do not need an offset

If a centered crop is enough, skip the filter. Timeline slots default to fit cover and the default output is 1080x1920, so the landscape source is cropped to fill the frame, and the whole job is $1.00. Use the filter route only when the subject sits off center and you need an x offset, or when you need two different crops. Also check the 500 MB limit on the result, as in the size post, and see the crop fraction table for other ratios.

Keeping audio and the join clean

Video trim keeps audio by default, so each half carries its own track. The Timeline needs an audio spine, so use the original 600 second audio file with audio.duration_seconds 600, and the slots set only the picture. If your audio is inside the video, detach it first with audio detach, which returns a durable wav or mp3.

Cut at 300.0 exactly and set the second slot's start to 300. Slots must increase in start time, and coverage can stop at most 0.5 seconds before the end of the spine, so slot two should run its full 300 seconds.