How to Stream Vertically and Horizontally on Twitch

As more viewers watch Twitch on their phones, Dual Format Streaming helps your stream look its best on both mobile and desktop by broadcasting vertical and horizontal layouts at the same time.

Dual Format Streaming sends two versions of your broadcast to Twitch:

• A horizontal 16:9 layout for desktop, TV, and landscape viewing
• A vertical 9:16 layout for phones held upright

You still manage one Twitch broadcast, so you do not need two independent streams.

Twitch also creates horizontal and vertical versions of your Clips and VODs.

• A Twitch account
• OBS Studio 32.0 or newer
• The latest version of Aitum Vertical
• Twitch Enhanced Broadcasting
• A computer that meets Twitch’s Dual Format system requirements
• At least 12.5 Mbps upload speed for 1080p, or 13.5 Mbps without added server-side transcode support
  • You can check whether your account has added server-side support under Creator Dashboard > Settings > Stream.

Twitch recommends a 1080 × 1920 vertical canvas. Your regular OBS canvas handles the horizontal stream, while Aitum Vertical manages the 9:16 layout.

Aitum Vertical adds a separate vertical canvas to OBS. Close OBS, download and install the latest version of Aitum Vertical, then reopen OBS. You should see an additional vertical canvas and related Aitum controls in the interface.

In OBS:

1. Select Settings > Stream.
2. Connect or select your Twitch account.
3. Find Multitrack Video.
4. Enable Enhanced Broadcasting.
5. Select Aitum Vertical as your additional canvas.
6. Select Apply, then OK.

Twitch recommends disabling Aitum’s Backtrack feature for this setup. Open Aitum settings, go to General, then clear the Backtrack option.

Your existing OBS canvas remains the horizontal version of your stream. Before creating the vertical layout, confirm that your horizontal scenes contain everything viewers need to see.

Your base and output resolutions are available under Settings > Video.

Set your Aitum canvas to a vertical resolution such as 1080 × 1920. Add existing OBS sources to the new canvas and position them for mobile viewing.

Create a vertical counterpart for each horizontal scene. Aitum Vertical links corresponding scenes so scene changes stay synchronized across both canvases. When you switch to your break scene, for example, viewers should receive the correct break layout regardless of format.

Preview every horizontal and vertical scene before going live. Look for cropped gameplay, covered interface elements, unreadable text, incorrect camera framing, or alerts that extend beyond the vertical canvas. You should also monitor OBS for encoder overload, dropped frames, or unusually high system usage.

Start your stream from OBS. Open your channel on desktop and mobile to confirm that Twitch is receiving both formats correctly.

Dual Format Streaming introduces more scenes and sources to manage during a broadcast. With Stream Deck and OBS Studio plugin, you can control OBS actions directly from physical keys.

Useful controls include:

• Starting or stopping your stream
• Switching scenes
• Showing or hiding sources
• Muting or unmuting audio
• Triggering transitions
• Saving replays

You can also use Multi Actions to combine related steps. One key could switch to your live scene, adjust your lighting, and start your broadcast in sequence.

Twitch Dual Format Streaming gives desktop and mobile viewers layouts designed for their screens through a single broadcast. Once your horizontal and vertical scenes are built and linked, Stream Deck can help you control scenes, sources, audio, and other live production actions from one place.