Threads video over 5 minutes: split an AI video with Sume video trim

Threads accepts videos of up to 5 minutes, so a longer AI video has to be split into parts. On Sume, POST /v1/video-trim cuts one range into a new MP4 for $0.02 per job, and leaves the source unchanged, so a 12-minute video becomes three jobs of up to 5 minutes each, or $0.06 in trim fees.

The 5-minute limit comes from the official Threads account's post on video length, read on 2026-10-07. The trim details are from the video trim guide.

Trim facts

Everything in this table is from the Sume docs.

Plan the cuts

Cut at natural breaks, not at exactly 300 seconds. A part that ends mid-sentence is a worse post than a part that ends at 4:40.

• Use exact precision when a cut must start on a given frame, and keyframe when speed matters more than the last frame.
• Keep each part under 300 seconds, with a margin for the container.
• A source longer than 1800 seconds must be reduced first, since that is the limit for the route.
• Each part is a new file. If the video is AI-generated, give every part the same disclosure.

Submit the jobs

Trim is an async job like the other media tools. Send one request per part and poll /v1/jobs/:id for each, as described in Jobs and results. Use a different Idempotency-Key per part and a stable key per retry, so a network retry does not create a second paid job.

Think before you split

A 5-minute AI video on Threads is long for the format. Check whether a 60-second cut of the best part would carry the post, and link to the full video elsewhere. When you do post several parts, post them in order and number them. For one file across placements, see one MP4 for Reels, Stories and Threads, and for a cut-down use case see the bumper from a long video.

What we did not verify

We read the 5-minute limit from one official post and did not find a Threads help page with a file-size or format list, so check the app before a large upload. Meta may label identical copies of AI media across its apps; see that post.