1. The Experiment: Meeting Viewers Where They Watch

People don’t all watch the same way. Some are on a desktop or a TV with a wide screen, and a huge number are on their phone, held upright, scrolling. For years I streamed in one shape — widescreen — and asked phone viewers to turn their device sideways or squint.

So I tried something different: send two versions of the same stream at once. A horizontal 16:9 version for big screens, and a vertical 9:16 version built for phones. The goal was simple: get more viewers by giving each of them their preferred screen.

There was a second reason too. Both YouTube and Twitch now show vertical live streams in their mobile, swipe-style feeds. On YouTube, a vertical stream can appear right in the Shorts feed, in front of people who have never heard of you. A widescreen-only stream isn’t eligible for that at all.

2. The Setup

Here’s what I’m running. If you stream with OBS, you can copy this almost exactly.

🔧 The tools

• OBS Studio as the main broadcaster.
• Aitum Vertical (free OBS plugin). It adds a second, vertical canvas with its own scenes, its own sources, and its own stream output.
• Custom HTML overlays I built myself, loaded as OBS Browser sources (more on those below).

📐 The vertical layout

A phone screen isn’t just a narrow TV. TikTok and YouTube draw their own buttons and chat over the top and bottom of your stream, so the layout has to dodge them:

• Top (~10–15%) — covered by your profile name and LIVE badge.
• Bottom (~25–30%) — covered by scrolling comments and gifts.
• Right edge — covered by the like, share, and gift buttons.

So my vertical canvas (1080×1920) puts the cam near the top (slightly inset so the profile badge doesn’t sit on my face), gameplay or the main action in the middle (the only area that’s reliably clear), and the logo at the bottom, where it’s fine if chat covers it. For karaoke streams, where I’m the content, the cam moves to the middle and gets bigger.

📶 Bitrate

The plugin suggested 6000 kbps for vertical, which sounds like a lot. It’s reasonable for 1080×1920, but remember the vertical stream runs alongside your main stream. The rule I use:

▶️ YouTube: two stream keys

YouTube can actually build a vertical version for you automatically — it’s on by default and center-crops your widescreen stream. You can switch it to Fit to phone width or Stacked under Live Control Room → Manage → Edit layout. But a center crop chops off anything in the corners, like a facecam. I wanted full control, so I send my own vertical feed:

1. In YouTube Studio → Live Control Room → Stream, change the vertical preview dropdown from Auto to Encoder.
2. Pick a second stream key for the vertical feed — it must be different from your horizontal key.
3. In the Aitum Vertical dock settings → Stream, use server rtmp://a.rtmp.youtube.com/live2 and that second key.

Viewers in the Shorts feed get the vertical version, everyone else gets horizontal, and both share the same live chat. One catch: you have to set this up before you go live — you can’t add the vertical format mid-stream.

🟣 Twitch: Dual Format

Twitch rolled out Dual Format streaming to everyone in June 2026, and it works differently from YouTube. It runs through Twitch’s Enhanced Broadcasting (OBS → Settings → Stream → Multitrack Streaming) together with the Aitum Vertical plugin, and Twitch recommends OBS 32 or newer.

3. What Broke (and How I Fixed It)

This is the part I wish someone had written down before I started.

4. The Results

I ran a test SETHaoke stream with the vertical feed going to YouTube. Here’s what the analytics showed:

For context: across the previous 90 days, all of my live streams combined got 837 views. One vertical stream pulled more than half of that in two days — and nearly every one of those views came from a feed that a widescreen-only stream can’t even appear in.

Reach: huge win. But then there’s the other half of the story…

Metric	Result	What it means
Total watch time	0.3 hours	About 2 seconds per view
Average concurrent viewers	1	People saw it and swiped on
Chat messages	3	Almost nobody stopped to talk

So the vertical feed is putting me in front of far more people than ever — but they’re deciding in a second or two, and most of them are scrolling past.

5. What I Learned

• The vertical feed is a discovery engine, not a living room. It’s the same thing I’ve seen on TikTok LIVE: tons of people pass through, few stay. That’s normal for swipe feeds.
• The first 2 seconds are everything. In a feed full of faces, a small cam and a quiet moment get skipped. Dead air between songs is exactly when viewers leave.
• Most viewers will never type. I’ve said hello a million times to silent rooms. People scrolling one-thumbed in bed are listening, not chatting — so the stream has to be entertaining with zero chat, like a radio host who assumes the room is full.
• Ask for tiny actions, not conversations. “Tap the screen” or “drop a 💙” takes half a second. “Say hi” asks someone to start a conversation. And on TikTok, “send a heart” can sound like asking for a paid gift — taps are the free version.
• People scroll with the sound off. If the premise isn’t written on screen, a lot of viewers never find out what the stream is.

6. Where We Go From Here

The fix for the 2-second problem is to make the vertical feed explain itself instantly and give viewers something to do. So I built a set of custom HTML overlays — each one is a single file loaded as an OBS Browser source, styled to match my channel:

Overlay	What it does
🌌 Animated background	Drifting glow, a moving grid, and floating particles to fill empty space behind the cam and gameplay.
🎤 SETHaoke “Now Singing” banner	LIVE badge, the current song and artist (editable live), and a ticker: song requests, “just swiped in? type 💙,” chat picks the next song.
👽 Sims community banner	“Join our community — we’ll create a Sim for YOU!” plus a “Newest resident” shout-out for the viewer whose Sim just moved in.
👆 TikTok tap banner	A big animated “TAP THE SCREEN” with floating hearts and free-action prompts: tap, follow, share.
⏸️ BRB screen	Full-screen “Be Right Back” with an optional countdown and rotating chat prompts, so breaks don’t empty the room. Works on both canvases.

Alongside the overlays, the plan for the next streams:

• Bigger face, constant motion on the vertical canvas.
• No dead air — fill song transitions with talk, a piano riff, or a sound effect.
• Talk to newcomers the way a radio host would, and recap what’s happening every few minutes for people just arriving.
• Clip the best moments into Shorts with Backtrack, each one linking back to the full stream.

📊 What I’ll measure in Part 2

YouTube publishes vertical-only stats about 24 hours after a stream. I’m watching two numbers:

1. Average concurrent viewers — moving from 1 to 3–5 would be real progress.
2. Watch time per view — moving from ~2 seconds to 10–15 seconds means the hook is working.

If reach stays where it is and those two numbers climb, the swipe-throughs start turning into actual viewers. I’ll post the before-and-after in Part 2.