Twitch dual format streaming(what it costs your encoder, and what it does to your VODs)

# What dual format actually sends to Twitch

Two video feeds leave your machine instead of one. A standard horizontal broadcast, and a full-screen vertical broadcast built on a separate canvas in your streaming software. Twitch then decides which one each viewer gets^[1]. Desktop and TV keep the classic 16:9 player. Mobile viewers holding the phone upright get the vertical feed; if they rotate the phone they get the horizontal one full-screen, and they can tap the video to switch views at any time.

Viewers see a one-time notice the first time they land on a dual format stream, explaining that they can switch. After that it is silent — vertical by default on mobile, with a classic-split icon on the right of the player^[1].

Twitch's stated reason for building it is blunt: "70% of new viewers are coming to Twitch on mobile"^[2]. The old answer to a phone viewer was a letterboxed 16:9 rectangle with two black bars and chat crammed underneath. Dual format is the platform admitting that was never good enough.

A useful thing about dual format is how little it changes elsewhere. Three things stay exactly as they were^[1]:

• Chat, subscriptions, gift subs and cheering all work identically whichever view the viewer is in. Viewers can also tap chat to show more of it, less of it, or none of it.
• There are no regional restrictions on dual format streams. (2K viewing does have regional limits, which matters if you run both — see the requirements section.)
• You can still simulcast. Restreaming to YouTube, Kick or anywhere else through a restreaming service works alongside dual format on Twitch.

# The requirements split into two very different tiers

"Dual Format Streaming is now available to all streamers on Twitch" is the sentence that got quoted everywhere^[1]. It is true. It is also the first half of a sentence whose second half decides whether the feature is cheap or expensive for you: "Partners and select Affiliates also get server-side transcode support."

That flag is not a cosmetic perk. It changes what your GPU is asked to do. With added server-side transcode support, your machine encodes two tracks — one 16:9, one 9:16 — and Twitch's datacentres generate every lower quality from there. Without it, your machine produces the entire quality ladder for both formats itself: a minimum of four tracks and up to six at 1080p, a minimum of five and up to seven at 1440p^[1].

Read the GPU row twice. On the supported side the floor is a GTX 900-series card, which shipped in 2014 and is sitting in a lot of second-hand streaming PCs. On the unsupported side it is an RTX 3070. That is not a nudge upward, it is a different machine. The operating-system row moves too: without transcode support the requirement is Windows 10 or 11 only, and the Mac M1 entry disappears entirely.

There is a second, quieter benefit that matters more than the bandwidth number. Before the transcode change, dual format vertical streams "typically only got 1080 and 360"^[1]. A phone viewer on patchy cellular had exactly one fallback, and it was 360p. With transcode support the vertical feed now gets the full ladder — 1080 source, 720, 480, 360 and 160p — and so does the horizontal one. For a feature whose entire premise is mobile viewers on mobile connections, that gap was doing real damage.

To find out which side of the table you are on, open your Creator Dashboard and go to Stream Settings → Advanced Broadcast Settings^[1]. Two caveats worth knowing before you build a workflow on it. Twitch says the resource is limited and "we can only guarantee it for Partners at this time". And it can be withdrawn — the help article lists long periods of inactivity, or losing Partner or Affiliate status, as reasons Twitch may stop providing it.

# Setting it up in OBS with Aitum Vertical

Twitch documents OBS plus the Aitum Vertical plugin as the most common setup, and it is the one the official walkthrough uses^[1]. Before you start, check your OBS version. Dual format needs OBS Studio 32.0.0 or newer — not the 30.2 figure quoted on the Enhanced Broadcasting page^[3], which is the floor for Enhanced Broadcasting generally, not for dual format. Streamers running 31.x can enable Enhanced Broadcasting fine and then wonder why the Additional Canvas dropdown is empty.

• Install the Aitum Vertical plugin, then open OBS.
• Settings → Stream. Tick Enhanced Broadcasting under "Multitrack Video".
• In the same window, set Additional Canvas to Aitum Vertical. If it is not in the list, close OBS, reopen it and look again — the dropdown only populates after the plugin has been loaded once.
• Optional but recommended by Twitch: in the Aitum Vertical dock, click the gear icon and untick "Backtrack runs while streaming/recording". It reduces load on the machine.
• Turn on the Vertical Scenes and Vertical Sources docks from the top menu.
• Build your vertical scenes. Use the "+" button in the Vertical Sources panel to pull in the scenes, game capture, webcam and alerts you already have, then rearrange each for the tall frame. You do not need to rebuild anything from scratch.
• Link the two sets: right-click a vertical scene in the Vertical Scenes panel, choose Linked Scenes, and pick the horizontal scenes it should follow. Linked scenes switch together, so one hotkey moves both canvases.
• Press Start Streaming in OBS.

That last step is where people get stuck. The vertical canvas has its own green "Go Live" button and you do not press it. Pressing Start Streaming in OBS takes both feeds live^[1].

Three ways to confirm it actually worked

• Run a short test stream and open your own channel in the Twitch mobile app. This is the only check that shows you what viewers see.
• On desktop, open Stream Manager and click the orientation icon next to the gear in Stream Preview to flip to the vertical feed.
• Check the stream health at inspector.twitch.tv — two feeds mean twice the opportunity for one of them to be quietly dropping frames. Our guide to Twitch Inspector covers reading that graph.

Not an OBS user? Streamlabs, Streamrun, XSplit and Meld all support dual format with no plugin required, and StreamElements publishes its own OBS plugin as an alternative to Aitum^[1]. If you are still choosing an encoder, our streaming software guide and the Streamlabs vs OBS comparison both cover the trade-offs.

# Designing for a canvas Twitch draws on top of

The vertical canvas is 1080 × 1920, a straight 9:16. What makes it different from designing a TikTok layout is that Twitch overlays its own interface — chat and player controls — on top of your video in the mobile view^[1]. Anything you place near the bottom edge is competing with chat for the same pixels, so keep gameplay HUDs, your camera and any text you actually need read in the centre safe zone.

The single most common wasted effort here is building a chat overlay into the vertical scene. Do not. Twitch adds chat to the vertical view automatically, and a browser-source chat widget on the canvas gives mobile viewers two chats stacked on one screen^[1].

• Start with two or three vertical scenes, not a vertical twin of everything you own. Twitch's own advice is that you do not need a vertical version of every scene on day one.
• Switch scenes from the horizontal menu once they are linked, not from the vertical panel. The link is one-directional in practice and driving it from the wrong side desynchronises the two feeds.
• Scale the webcam up. A camera sized for a 1920-wide canvas is a postage stamp on a phone.
• Preview before you go live. Confirm the camera, overlays and alerts all fit the tall frame rather than discovering it mid-stream.

If your encoder starts complaining, Twitch's documented relief valve is Settings → Stream → Multitrack Video: lower the maximum bandwidth, or drop maximum video tracks from Auto to 5 or 4^[1]. That trades some of the quality ladder for headroom, which on a machine without transcode support is often the difference between a stable stream and a stuttering one.

# What happens to your VODs and clips

This is the part of dual format that no third-party guide seems to mention, and it has a real workflow consequence. Twitch generates both a horizontal and a vertical version of your clips and VODs^[2] — but they do not live equally long.

Read the first row against the second. An Affiliate has a 14-day VOD window, and for half of it the vertical cut is already gone. If your plan was to stream vertically all week and then mine the VODs for shorts on Sunday, half your source material has expired before you open the editor.

The practical answer is to clip while you are live, or immediately after, because clips carry both orientations and never expire. That makes the clip button a genuine archive tool on a dual format channel rather than a highlight nicety. Our guide to Twitch clips covers the editor and the export paths; the VOD guide covers retention in general.

# Phone streamers are still locked out

Here is the irony at the centre of this feature. Dual format exists because 70% of new Twitch viewers arrive on a phone. It is not available to people who broadcast from a phone.

Twitch states it plainly: if you stream directly from the Twitch mobile app, dual format is not available yet. You can stream vertically from the app, but your viewers cannot switch to horizontal, and desktop viewers get the vertical feed too^[1] — which is the worst of both worlds, a tall video letterboxed inside a wide player.

The documented exception is a cloud-OBS or otherwise advanced mobile setup that meets the Enhanced Broadcasting requirements. That is a real path, and it is also several steps beyond "open the app and press go live". Twitch says it is "working on adding more Dual Format support for IRL streamers over time", which is an honest way of saying not yet. If you are running an IRL channel from a backpack, our mobile and IRL broadcasting guide is the more useful read for now.

# When the vertical feed does not show up

Twitch publishes a troubleshooting list for the OBS and Aitum path^[1]. These are the five failures that actually happen, in rough order of frequency.

The vertical stream is not appearing on Twitch at all

Check three things in order: Enhanced Broadcasting is ticked, Additional Canvas is set to Aitum Vertical, and the plugin is installed, enabled and connected to your Twitch account inside OBS. In practice the third one is usually the culprit — the plugin can be installed and still not authorised.

The vertical stream is live but showing the wrong layout

Open the Aitum Vertical dock and confirm which vertical scene is actually selected. If your sources look cropped or off-centre, they are almost certainly a reused horizontal scene rather than a vertical-specific one.

CPU or GPU usage went through the roof

• Reduce the maximum bandwidth in OBS under Settings → Stream → Multitrack Video.
• Drop the maximum video tracks setting from Auto down to 5, or to 4 if it is still struggling. This matters most if you are also recording locally or multistreaming, both of which compete for the same encoder.
• Close background applications and browser windows.
• If you are on the "without transcode support" side of the requirements table, check your GPU against it honestly. An RTX 3070 floor for 1080p is not a suggestion.

The vertical feed has no audio, or the audio does not match

The same audio sources have to be added and linked to both the horizontal and the vertical scenes. Check the OBS audio monitoring settings are consistent across scenes, and if you route through virtual audio cables or third-party software, confirm it is assigned to both outputs rather than just the original one.

OBS says "failed to connect" for the vertical stream

• Confirm your upload actually meets the minimum for your tier — 12.5 Mbps with transcode support at 1080p, 13.5 Mbps without.
• Confirm you are logged into Twitch inside OBS and Aitum Vertical is still selected as the additional canvas.
• Restart OBS. If it persists, reinstall the plugin — a plugin left behind by an OBS major-version upgrade is a common cause.

# Turning it off without turning off everything

You can stop streaming in dual format whenever you like, and there are two levels to it^[1]. To keep Enhanced Broadcasting for your horizontal stream but stop sending a vertical feed, set Additional Canvas to None. To back out of the whole system, untick Enable Enhanced Broadcasting — which also gives up 2K and multiple client-side encodes, so it is a bigger step than it looks.

Worth trying the first option before the second. Most of the performance complaints people attribute to dual format are actually the cost of encoding a full quality ladder locally, and setting the canvas to None removes the vertical feed while leaving your existing horizontal quality options intact.

# So should you switch it on?

The answer depends almost entirely on which row of the requirements table you are in, and it is worth being specific rather than encouraging.

If you have added server-side transcode support

Turn it on. Your machine encodes two tracks instead of one, the GPU floor is a card from 2014, and 12.5 Mbps of upload is inside what most fibre and decent cable connections deliver. The cost is an evening building two or three vertical scenes. If you are a Partner you have this by default; check Advanced Broadcast Settings to be sure.

If you do not have it

Do the arithmetic before you enable anything. You are asking your GPU for four to six encodes and your connection for 13.5 Mbps sustained, on Windows only. On a GTX 1660 or a Radeon 5700 you are below the documented floor, and what you will get is dropped frames on the horizontal feed that your existing audience is actually watching. Trading a stable stream for a second one nobody has found yet is a bad trade. The honest move is to wait for Affiliate transcode access rather than force it.

If you stream from a phone

It is not available. See the section above.

What can be said is that Twitch is pushing it. Between 20 and 27 August 2026 the platform ran a promotion adding one bonus gift sub for every bundle of five bought on any channel streaming in dual format, automatic for Affiliates and Partners with no sign-up^[4]. That window has closed, so do not switch the feature on expecting the bonus. It is useful only as a signal of how much the platform wants this adopted — and platforms that want something adopted tend to weight it in discovery eventually.

# Bottom line

Dual format is a genuinely good feature wearing a misleading label. "Available to all streamers" describes permission, not capability — the hardware and bandwidth bill differs by roughly six years of GPU generation depending on whether Twitch is doing the transcoding for you. Check Advanced Broadcast Settings in your Creator Dashboard first, and let that answer decide whether you spend the evening building vertical scenes.

If you do enable it, remember the seven-day rule. The vertical version of every VOD expires a week after the stream, while clips keep both orientations forever. On a dual format channel, clipping stops being optional housekeeping and becomes the only reliable way to keep your vertical footage.