Playlist to Shorts series: audit every file first with video inspect

YouTube turns a playlist into a Shorts series only if it contains nothing but Shorts, and a Short for this purpose is portrait or square and at most 180 seconds. Before you choose Add show features, probe each source file with Sume's video inspect and drop anything wider than tall or longer than 180 seconds.

The rule is on YouTube's Create shows from your videos page (read 2026-10-06): "To package your Shorts into an episodic series, the playlist must only contain Shorts." The same page says the videos "must be portrait or square in dimension and have a maximum duration of 180 seconds."

What does the playlist check look like?

Each file in your own library gets one probe-only call, then a three-line verdict.

How do I probe a file with Sume?

Call POST /v1/video-inspect with video_url set to the file's media.sume.com URL, an Idempotency-Key, and frames: false so Sume returns only the probe and no stills. The file has to be in your workspace already; import it first with POST /v1/media-imports. Read the dimensions and duration from the probe object in the result.

The default mode is sync and waits up to 30 seconds, then returns 202 with a job to poll. See the video inspect docs for the full request and for the live price.

What do I do with the files that fail?

A 4-minute vertical file can be cut into two episodes with video trim. A 16:9 file can be re-rendered into a vertical frame with Timeline's blur fit, though a dedicated vertical cut usually reads better. Keep a note of which source became which episode, because YouTube renumbers other episodes when you edit or delete one.