YouTube video A/B test of three cuts: make hook variants with trim

YouTube says that, coming soon, you will be able to test up to three video cuts to see which hook performs best. Sume cannot enter that test for you, but it can make the three candidates: three POST /v1/video-trim jobs on one source clip, each with a different start, at $0.02 per job.

YouTube's statement is from its Made on YouTube post, read 2026-10-01; trim behavior and the price are from Sume's Video trim docs.

What did YouTube announce?

The post lists video A/B testing as coming soon and says it builds on Studio's title and thumbnail testing, which the post says creators have used in more than 40 million experiments. It gives no date and no rules for the video test, so check YouTube Studio for availability and limits.

What does one trim job give me?

Trim takes one media.sume.com clip in your workspace and returns a new MP4 of the range [start, end); the source is untouched. Import an outside file first with POST /v1/media-imports. Idempotency-Key is required, and exactly one of end or duration is allowed.

How do I make three hook cuts?

Pick three in-points that open on different moments, keep the length the same, and send one job per cut with its own key. A range cut is one continuous piece of the source. If a hook needs lines reordered, trim the pieces and join them in Timeline 1.0.

const starts = [0, 4, 9];
for (const [i, start] of starts.entries()) {
  const res = await fetch("https://api.sume.com/v1/video-trim", {
    method: "POST",
    headers: {
      Authorization: "Bearer " + process.env.SUME_API_KEY,
      "Content-Type": "application/json",
      "Idempotency-Key": "hook-cut-" + (i + 1) + "-v1",
    },
    body: JSON.stringify({
      video_url: process.env.SOURCE_VIDEO_URL,
      start,
      duration: 20,
    }),
  });
  console.log(i + 1, res.status, await res.json());
}

How do I get the results?

Default mode is async. Poll GET /v1/jobs/:id/status, then read GET /v1/jobs/:id/result, which returns a video_url for the new MP4. Name the files by hook so you can match the YouTube test arms. For one cut to several feed lengths, see cut a product video into feed cutdowns.