Video filter crops 16:9 to 9:16 only up to 300 seconds of source

Sume's video filter accepts a source of at most 300 seconds, so a 16:9 recording longer than 5 minutes fails with output_duration_exceeded if you crop it directly. Trim it into pieces of 300 seconds or less first, then send each piece through a crop op with x 0.341796875, y 0, width 0.31640625, height 1.

The limit is stated in the video filter docs (read 2026-10-06): "source ≤ 300 s", with output_duration_exceeded as the refusal code. Video trim, by contrast, accepts a source up to 1800 seconds and an output up to 900 (video trim docs).

Where do the crop fractions come from?

A 9:16 window inside a 16:9 frame is as tall as the frame and (9/16) / (16/9) = 81/256 of its width, which is 0.31640625. Centered, it starts at (1 - 0.31640625) / 2 = 0.341796875. The docs say crop takes fractions of the source frame and the compiler rounds to even values for yuv420p, so you never send pixels.

What is the order for a long recording?

First, POST /v1/video-trim for each range of 300 seconds or less (a Short is at most 180 seconds anyway, per YouTube Help). Second, POST /v1/video-filter/check with the crop op, which is free and reports valid without encoding. Third, POST /v1/video-filter for each trimmed piece. Each trim and each filter job is $0.02.

The crop keeps the source's frame rate and audio. Put the result in a Timeline video[] slot, where fit: cover scales the narrow strip to the 1080x1920 default output.