Vertical video, explained for builders

Vertical video is portrait 9:16 footage — typically 1080x1920 — that fills a phone screen top to bottom. It is the native format of Instagram Reels, TikTok, and YouTube Shorts, where almost everyone watches one-handed, holding their phone upright. Get the format right and your video occupies the whole screen. Get it wrong and it sits in a small landscape box with dead space above and below, which reads as off-platform and gets skipped.

If you are a founder or builder, this is the part nobody warned you about. You can have a sharp clip and still lose because it was framed for a TV, not a thumb. The villain is the editing tax: the assumption that competing in the feed means learning aspect ratios, safe zones, and reframing — a whole craft you never signed up for when you set out to ship a product.

We are builders too, and we would rather ship than reframe footage by hand. OpenNolan is a Mac app where an AI agent composes the whole reel vertical-first — so 9:16 is the default, not a manual conversion you do every time. This page covers the format itself; the app just makes living in it effortless.

9:16 aspect ratio and the resolutions that matter

Aspect ratio is the shape of the frame: width to height. Vertical video uses 9:16, meaning the frame is taller than it is wide — the mirror image of the 16:9 you see on a TV or YouTube desktop. On a phone held upright, 9:16 fills every pixel.

The resolution you want is 1080x1920 (often called 1080p vertical or Full HD portrait). That is the sweet spot for Reels, TikTok, and Shorts: crisp on modern phones without bloating file size. Higher options exist — 4K vertical is 2160x3840 — but 1080x1920 is the standard most short-form is shot, edited, and delivered in.

• 9:16 = portrait, taller than wide
• 1080x1920 is the standard short-form resolution
• 16:9 (landscape) is the opposite shape and gets letterboxed
• Square 1:1 and 4:5 are feed-friendly but not full-screen

Safe zones: keep your content clear of the UI

If your caption lands under the share button, nobody reads it. Design for the safe zone, not the full canvas.

A full 9:16 frame is not all usable space. Each platform stacks its own interface on top of your video — the caption and handle along the bottom, the like, comment, share, and follow buttons up the right edge, and a progress bar or profile pic near the top. Anything important you place in those areas gets covered.

The safe zone is the central band that stays visible across Reels, TikTok, and Shorts. Keep your subject, your text, and your hook inside it. A reliable rule of thumb: leave roughly the top ~10% and bottom ~20% of the frame clear, and pull captions and key visuals away from the right edge so the action buttons do not sit on top of your words.

Why vertical wins on mobile feeds

Phones are held upright the overwhelming majority of the time, and the feed is an endless vertical scroll. A 9:16 video meets the viewer exactly where their thumb already is: full screen, no tilting, no pinch-to-zoom, no black bars signaling that this clip came from somewhere else.

That format match buys you the only thing that matters in short-form — the first second. A landscape clip in a vertical feed wastes most of the screen and visually flags itself as repurposed, which costs you attention before your hook even plays. Vertical is table stakes for short-form video; it is the container everything else rides in.

Converting landscape to vertical (and why composing vertical-first beats it)

If your footage is landscape, you have a few ways to reach 9:16. You can crop in to the most important part of the frame, which fills the screen but throws away the sides. You can pad with a blurred or solid background above and below the clip, which keeps everything but shrinks your subject. Or you can reframe dynamically, panning the crop to follow the action across a wider shot.

Every one of these is a manual judgment call per clip — where to crop, what to lose, when to pan. That is the editing tax in miniature. The better path is to compose vertical-first: think in 9:16 from the start so your subject and text are already built for the tall frame, instead of rescued into it after the fact.

• Crop — fills the frame, loses the edges
• Pad — keeps the whole shot, shrinks the subject
• Reframe — pans the crop to follow the action
• Vertical-first — skip the conversion, build for 9:16 from the start

How OpenNolan composes vertical-first

OpenNolan builds for 9:16 / 1080x1920 by default. The AI agent assembles the whole reel inside the vertical frame — placing your clips, pulling B-roll and images from the web, adding music and sound effects, and writing burned-in captions — all positioned for the tall canvas and the platform safe zones rather than squeezed in afterward.

Because the app is render-once, edit-cheap, you are not locked in. After the first render, repositioning a clip, nudging text out of the UI band, or retiming a cut previews instantly without re-rendering the whole video. It runs on your Mac with your own AI key — bring your own key, no subscription, no markup. The app is open source and still in development; the waitlist is open now.

• 9:16 / 1080x1920 vertical by default
• Clips, B-roll, captions, and motion placed for the tall frame
• Instant reposition after the first render
• Mac-native, local-first, bring your own key

Frequently asked questions