How to stream Twitch Dual Format from OBS (horizontal and vertical at once)

Updated August 2026. About an 8 minute read.

Twitch turned on Dual Format for everyone on June 17, 2026. One stream, two shapes: desktop viewers get your normal 16:9 broadcast and phone viewers get a real 9:16 feed instead of a shrunken letterboxed strip. The feature itself is free.

The annoying part is everything around it. Which plugin actually drives the vertical canvas, and how do you rebuild every one of your scenes in 9:16 without losing an evening to dragging sources around?

This guide covers the whole path. It assumes OBS 31.1 or newer.

What Dual Format actually does

With Dual Format on, Twitch receives two renditions of your stream. Desktop gets the wide one. The mobile app shows vertical viewers your 9:16 feed full screen, with Twitch's own chat drawn on top of it.

You control what each format shows. It is not an automatic crop. Your facecam can fill the top of the phone screen while gameplay sits below it, which is the entire reason to bother with any of this.

Under the hood it runs on Enhanced Broadcasting. Partners and most Affiliates get server-side transcoding for it. Check Settings, then Stream, in your Twitch dashboard for the Enhanced Broadcasting toggle.

Step 1: pick your vertical canvas tool

OBS 31.1 added multi-canvas plumbing, but the tool most stock-OBS streamers actually use is the free Aitum Vertical plugin (the obs-vertical-canvas project on GitHub). It adds a Vertical dock with its own scene list and preview, rendering a second 1080x1920 canvas next to your main one. Install it and restart OBS and the dock appears.

There are alternatives. Streamlabs Desktop has dual output built in if you live in that ecosystem, and StreamElements SE.Live covers it too. The rest of this guide uses Aitum Vertical.

Step 2: vertical versions of your scenes (the part everyone hates)

The plugin gives you an empty vertical canvas. Your existing scenes don't carry over. You're expected to rebuild your layout for 9:16 by hand: re-add the facecam, resize the gameplay, decide what happens to the chat box, repeat for every scene.

Plan on an hour for a typical five-scene setup, because a phone screen is a genuinely different design problem:

• Your facecam wants the top third, sized so your face reads at phone scale.
• Gameplay keeps its 16:9 shape (stretching looks terrible) and goes full width in the middle, which works out to about 1080x607 of the 1920 height.
• Twitch's mobile UI covers the top ~180px with the title area and the bottom ~320px with chat. Anything important in those bands gets sat on.
• Your chat box is probably redundant now. Twitch mobile draws chat over vertical streams on its own, so a burned-in chat shows twice.
• Wide overlay art, like top bars and 16:9 frames, has no vertical equivalent. Most of it just needs to be hidden.

You can absolutely do all that by hand. It's just tedious, which is why we built a shortcut.

Step 2, the fast way: SceneFlip

SceneFlip is free and runs in your browser. Nothing uploads anywhere.

1. In OBS: Scene Collection, then Export. That saves a .json copy of your scenes and touches nothing live.
2. Open SceneFlip and drop the file on it.
3. It works out what every source is (facecam, gameplay, chat, alerts, overlays, text, audio) and rebuilds each scene at 1080x1920 using the rules above. You get a side-by-side preview and a plain list of what it changed and why.
4. Download the result. In OBS: Scene Collection, then Import, pick the file, switch to it. Your original collection is untouched. The imported copy already has the vertical scenes attached to the Aitum Vertical canvas, linked up so the plugin switches vertical scenes when you switch main scenes.

Everything it outputs is a normal OBS scene, so you can fine-tune anything in the dock afterward. Mirrored cameras stay mirrored. Crops and locks survive. Nothing gets deleted, only hidden, and the report tells you what and why.

Step 3: turn it on and go live

1. In the Aitum Vertical dock settings, confirm the vertical canvas streams to Twitch as the second format. The plugin's Twitch preset handles the endpoint.
2. In your Twitch dashboard under Settings, then Stream, enable Enhanced Broadcasting (and Dual Format if it shows as its own toggle).
3. Go live like normal, then check the Twitch mobile app. Your stream should render full screen vertical with the new layout.

When something looks wrong

The Vertical dock shows no scenes after import. Make sure you actually switched to the imported collection, and that the Aitum plugin was installed before you imported. The vertical scenes live inside the collection; the dock lists them once that collection is active.

The camera looks huge or tiny on mobile. Resize it in the dock like any OBS source. SceneFlip sizes for a typical 16:9 camera, so an unusual aspect ratio may need a nudge.

Chat shows twice. Your burned-in chat source is visible on the vertical canvas. Hide it there, or re-run SceneFlip with the hide-chat option ticked (it's the default).

Frames drop after enabling dual output. You're encoding two videos now. Enhanced Broadcasting offloads what it can, but on an older GPU try dropping the vertical canvas to 30fps in the plugin settings. Phone screens are forgiving.

SceneFlip is a free tool for streamers going vertical. It runs entirely in your browser and your scene collection never leaves your machine.