How do you reframe a horizontal 16:9 talk or podcast to vertical 9:16 without losing the speaker, slides or group shots?

Why a 16:9 recording has to be cropped to become a Short

YouTube counts a video as a Short when it has a square or vertical aspect ratio and lasts up to three minutes. The rule applies to videos uploaded on or after October 15, 2024. YouTube tells creators who want to avoid Shorts classification to use a wider ratio such as 16:9, so a horizontal 16:9 upload stays a regular video even when it is under three minutes.

Placing the whole 16:9 frame inside a vertical canvas with black bars for an entire clip is not a good fix. YouTube's general advice is to avoid adding padding or black bars directly to the video, because padding interferes with the player's ability to adapt to the video size and the viewer's device. On a computer, YouTube's standard ratio is 16:9, and it may add its own padding around a 9:16 video in the browser.

How much of a 16:9 frame a 9:16 crop keeps

A 9:16 window cut at full height from a 16:9 frame keeps 31.6% of the width. The rest is outside the crop, so the real question is where to place that slice at each moment. At full height (x1.0), the slice can only move left and right. Zooming in shrinks it further, and each source pixel is enlarged more.

Source resolution affects how sharp the result looks. From a 1080p recording, the slice is scaled up to reach 1080 x 1920. From a 3840 x 2160 recording at x1.0, it is scaled down instead.

Keeping the speaker in frame

A good vertical crop follows the face, keeps the whole face inside the frame and avoids constant zooming. In shortshort, the tracker samples each selected passage 3 times per second with MediaPipe Face Detector. It aims to leave 0.35 face-width of space on each side of the face, and narrows that space rather than cut the face. It sets one base zoom level per shot: x1.04 when the face is 28% of the frame height or less, x1.0 otherwise. This base zoom changes only at a camera cut or a switch to another face, so the frame does not pump.

At a camera cut the tracker detects, the crop never pans across it. It holds its position, then jumps to the new framing, and the cut is located to within 1/30 s, one frame of the 30 fps export. Within a shot, small moves of the speaker are smoothed. If the detector loses the face for up to 1.5 s and finds it again in about the same place, the gap is bridged, but never across a cut.

A few words the AI marks as punch words get a brief push-in over 720 ms: up to 17% more zoom on a face under 30% of the frame height, up to 9% on a larger one, and less when a tighter crop would cut the face. It happens only on a tracked face, never on a full-image shot, and tops out near x1.22 (the x1.04 base times 1.17).

Slides, charts and wide shots: show them whole or crop around the subject

A slide cut down to a third of its width usually loses its text. The fix is to show the full picture for those moments only. In shortshort, the AI analysis flags moments to keep whole: slides, charts, essential on-screen text, or several subjects a vertical crop would cut off. Those moments are shown whole across the 1080 px width (1080 x 608 for a 16:9 source), over a blurred, darkened copy of the same video rather than black bars, even when a face is present.

Other wide shots are not shown whole. A wide shot with no usable face that the analysis did not flag fills the 9:16 frame, cropped around the subject the analysis pointed to, with a zoom between x1.0 and x1.08. A face under 10.5% of the frame height, which can be the case for a speaker filmed from far away on a stage, gets the same treatment. It is not zoomed in close.

A full-picture moment is still a picture framed inside a taller frame. Keep it for the moments where a crop would lose information, and let the speaker fill the frame the rest of the time.

Two-person podcasts, fast cuts and failed tracking

With two people in one fixed shot, shortshort follows the most prominent face, ranked on the detector's confidence and the face's size. It switches by visible face, not by voice: there is no speaker diarisation. If the other face becomes the most prominent for less than 1.5 s, the frame does not move. If it stays the most prominent for longer, the crop usually switches to it with a clean cut, not a pan. Who is speaking plays no part, so in a steady two-shot the crop can stay on the listener. If two faces carry similar weight and neither is above 20% of the frame height, no face is picked for that moment.

Very fast editing is handled with a fallback. If one passage has more than 29 shots, the tracker uses one fixed 9:16 frame at the average position. If in-browser tracking fails, the short is not tracked and the studio shows a notice saying so.

Vertical specs for YouTube Shorts, Instagram Reels and TikTok

The three platforms do not publish the same kind of figures. YouTube gives rules for organic Shorts. For Instagram Reels, the figures below come from Meta's ads guide, not from an organic upload page. For TikTok, they come from its In-Feed ads spec and its developer Media Transfer Guide. All were checked on September 22, 2026.

Safe zones matter for captions and slide text. For Reels ads, Meta suggests keeping at least 14% of the top, 35% of the bottom and 6% of each side free of text, logos and other important elements. TikTok's In-Feed ads page gives no single set of margins: the safe zone depends on the dimension, the ad caption length and any extra formats, and TikTok provides downloadable safe-zone files.

shortshort places captions in a fixed block 330 px above the bottom edge of the 1920 px frame, about 17%. That is inside the bottom 35% Meta suggests keeping clear for Reels ads, and the position cannot be moved. For an ad, turn captions off or use the caption-free copy in the Download all ZIP.

With shortshort

shortshort reframes each short automatically from one uploaded file (MP4, MOV or WebM, up to 3 hours and 2 GB). It tracks the face with MediaPipe, keeps one base zoom level per shot, cuts instead of panning at camera changes, and shows the slides, charts and group shots its analysis flags whole, over a blurred copy of the video. Tracking runs on every plan, including Free. A clip added or extended in the editor is not re-tracked. Export is 9:16 only, MP4 H.264 at 1080 x 1920 and 30 fps.

Sources

The official pages this guide relies on, with the day each one was read.

• Understand three-minute YouTube Shorts - YouTube Help, checked 22 September 2026.
• Upload YouTube Shorts - Computer - YouTube Help, checked 22 September 2026.
• Video resolution & aspect ratios - Computer - YouTube Help, checked 22 September 2026.
• Awareness Video Ad Specs on Instagram Reels | Facebook Ads Guide, checked 22 September 2026.
• TikTok Auction In-Feed Ads | TikTok Ads Manager, checked 22 September 2026.
• Media Transfer Guide | TikTok for Developers, checked 22 September 2026.

Related

• Make YouTube Shorts from a long videoTurn one long video file into YouTube Shorts: 1080 x 1920 MP4s of 15 to 90 seconds, cut on complete sentences and captioned. You upload them to YouTube.

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