Can one video run only on Shorts in a Video reach campaign? No pin

No. Google's YouTube Shorts ads asset specs page says that in multi-format Video view and Video reach campaigns, Google automatically optimizes delivery across the selected formats (in-stream, in-feed, Shorts), and you cannot restrict an individual video asset to a single format such as Shorts only. Format-level anchoring of an asset, called Creative Preferences, exists only in Demand Gen campaigns.

What you can do in a Video view or Video reach campaign is opt out of specific formats for the entire campaign.

Your options by campaign type

The page also gives the call-to-action timing, which differs by type and matters for where you place the hook.

Build the Shorts-first asset with Sume

Google recommends vertical, sound-on assets under 60 seconds for Shorts, because only the first 60 seconds of a longer video play in the feed. Make that cut with Sume video trim: send video_url, start and duration (0.2 to 900 seconds), and you get a new MP4 for $0.02 per job, source unchanged.

If your master is 16:9, Sume's timeline places a clip with fit set to cover, contain, stretch or blur on a vertical output, which is 1080x1920 by default. Pick blur to avoid empty bars.

Steps

• If a video must serve only on Shorts, put it in a Demand Gen campaign and set Creative Preferences there.
• If you run Video view or Video reach, accept automatic format mixing, or opt the unwanted formats out for the whole campaign.
• Cut the vertical version to 60 seconds or less and keep the hook before the CTA appears.
• Upload the video to YouTube first; the page says Shorts ads must be uploaded there as public or unlisted.

What this changes in the brief

Write the brief per campaign type. A Demand Gen brief can say 'Shorts-first vertical cut' and enforce it with Creative Preferences. A Video reach brief should assume that every asset may serve in-stream, in-feed and Shorts, so each asset has to hold up in all three: a clear first three seconds, captions burned in for sound-off viewing, and a hook that lands before the 10-second CTA.

That is also the argument for cutting two files from one master instead of one compromise file: a vertical 60-second version for Shorts-friendly delivery and a 16:9 version for in-stream.

Caveat

Table cells marked 'not stated' mean the page did not say, not that the answer is no. Google changes Ads help pages often; read the current page before building a media plan.