How to Multistream to YouTube Shorts and Twitch at the Same Time

Multistreaming to YouTube Shorts and Twitch sounds straightforward until you realize the two platforms want completely different video formats. Twitch expects a horizontal 16:9 stream; YouTube Shorts requires a vertical 9:16 layout. Most guides skip over this conflict entirely, leaving you with a Twitch stream that looks great and a YouTube output that never registers as a Short. This guide covers exactly how to handle both — the right tools, the right settings, and the step most people miss.

The Format Problem You Need to Understand First

This is the part most multistreaming tutorials gloss over, and it’s the reason even a correctly configured setup can fail in ways that aren’t obvious.

Standard multistreaming works by sending a single stream from your encoder to a routing service (or directly to multiple RTMP endpoints), which then forwards an identical copy to each platform. That identical copy is the problem. Twitch is built around horizontal, widescreen video — 1920×1080, 16:9 aspect ratio. YouTube Shorts requires the opposite: a vertical, portrait-orientation stream at 1080×1920, 9:16 aspect ratio. If you send the same horizontal stream to both destinations, YouTube receives it as a standard horizontal live video — not a Short.

YouTube does not convert your stream automatically. The platform classifies a live stream as Shorts-eligible only when the source signal is already vertical when it hits YouTube’s ingest server. There is no toggle inside YouTube Studio that flips a horizontal stream into a Short after the fact while you’re live.

The real challenge here isn’t just “stream to two places at once” — it’s “stream two different aspect ratios simultaneously to platforms that expect incompatible formats.” Every tool and method in this guide addresses that specific conflict in a different way.

Note: Some cloud multistreaming services advertise YouTube Shorts support, but what they actually deliver varies. Some transcode the signal on their end; others require your source encoder to already be vertical. Always check the current platform documentation before scheduling a live stream.

What You Need Before You Start

Before touching any settings, confirm you have all of the following in place:

• Verified YouTube channel — YouTube requires channel verification to enable live streaming at all. Live streaming via desktop encoder (the approach this guide uses) has no subscriber minimum but does require verification through YouTube Studio.

• Twitch account with stream key — Found in Twitch Creator Dashboard → Settings → Stream.

• YouTube Live stream key and RTMP URL — Generated in YouTube Studio → Go Live → Stream.

• Streaming software or service account — Either a working OBS Studio installation or an active Restream / StreamYard account.

• Stable upload speed — Minimum 10–15 Mbps for dual-stream output at acceptable quality; 20+ Mbps recommended for headroom.

Best Tools to Multistream to YouTube Shorts and Twitch

Three tools cover the realistic options for most creators. Here’s how they compare on the factors that matter most for this specific setup:

The decisive column is Vertical / Shorts Support. StreamYard can route a stream to YouTube, but it won’t produce a Shorts-compatible vertical signal without workarounds that aren’t built into its interface. Restream handles the format split more cleanly at the service level. OBS gives you the most precise control but requires you to build the vertical scene yourself. Choose your method based on that trade-off, then follow the corresponding walkthrough below.

Method 1 — Multistream to YouTube Shorts and Twitch with Restream.io

Restream is the recommended path for most creators. The platform handles authentication, stream routing, and per-destination output configuration through a single dashboard — removing most of the manual RTMP work.

Step 1 — Connect Your YouTube and Twitch Accounts in Restream

Log into your dashboard at restream.io. Navigate to Add Channel and select YouTube. You’ll be prompted to authenticate with your Google account and grant Restream permission to manage your YouTube Live streams. Repeat the process for Twitch — select Twitch from the channel list, sign in, and authorize the connection.

Once both channels appear as active destinations in your Restream dashboard, check that each is showing a connected status indicator before moving on.

Step 2 — Configure the YouTube Shorts Output (Vertical Format)

Click the gear icon next to your YouTube destination in the Restream channel list. Look for output resolution or stream format settings. If Restream’s current interface offers a portrait or vertical output option, select it — or manually enter 1080×1920 in the resolution field. This instructs Restream’s transcoder to deliver a vertical signal to YouTube, which is what triggers Shorts eligibility.

Important caveat: Restream’s vertical transcoding support has been updated incrementally, and the exact setting label may differ depending on your account tier. If a vertical output option doesn’t appear for your YouTube destination, you’ll need to send a vertical source signal from OBS directly — meaning your OBS canvas should be set to 1080×1920 before connecting to Restream. The OBS vertical canvas configuration is covered in Method 2.

Step 3 — Set Your Twitch Output to Horizontal 16:9

Click the settings icon next to your Twitch destination. Confirm the output resolution is 1920×1080 and set the bitrate within Twitch’s accepted range — up to 6,000 Kbps for standard accounts, up to 8,000 Kbps for partners. Select the ingest server geographically closest to your location for the lowest latency. Restream may handle server selection automatically, but manual selection is available in advanced destination settings if you need it.

Step 4 — Go Live from OBS Using the Restream RTMP Key

In your Restream dashboard, open Stream Setup and copy the provided RTMP URL and stream key. These are your Restream credentials — your encoder sends the stream here once, and Restream distributes it to both platforms.

Open OBS Studio. Go to Settings → Stream, set Service to Custom, and paste the Restream RTMP URL into the Server field and the stream key into the Stream Key field. Click OK.

Under Settings → Video, set your OBS canvas resolution based on how you’re handling vertical conversion:

• If Restream is transcoding to vertical for YouTube: keep OBS at 1920×1080

• If Restream is not transcoding and you need to supply a vertical source: set OBS canvas to 1080×1920 and rely on Restream’s Twitch destination settings to manage the output on that end

Click Start Streaming in OBS. Restream’s dashboard will show both destinations going live within 20–30 seconds.

Method 2 — Multistream for Free Using OBS Studio

For creators who’d rather avoid a subscription, OBS Studio combined with the obs-multi-rtmp plugin is the strongest free alternative. It requires more manual setup but gives you precise, independent control over each destination’s encoder output.

Install the obs-multi-rtmp Plugin

Download the plugin from its GitHub repository — search “obs-multi-rtmp GitHub” and select the result from the OBS community. Installation steps by OS:

• Windows: Run the installer package and restart OBS

• Mac: Place the plugin files in the OBS plugins directory, then restart OBS

After restarting, the plugin appears as a dockable panel inside OBS under View → Docks → Multiple RTMP Output.

Add YouTube and Twitch as Separate RTMP Outputs

Open the Multiple RTMP Output panel. Click Add to create a new output and enter the following for each platform:

• YouTube: Server = rtmp://a.rtmp.youtube.com/live2 | Stream Key = your YouTube key from YouTube Studio → Go Live

• Twitch: Server = your regional Twitch ingest URL (e.g., rtmp://live.twitch.tv/app) | Stream Key = your Twitch key from Creator Dashboard → Settings → Stream

Each output entry in the plugin panel supports its own bitrate, resolution, and keyframe interval — completely independent of your main OBS output. That per-destination encoding control is the core advantage of this plugin over stock OBS.

Handle the Vertical Canvas for YouTube Shorts

This is the most technically involved step in the free method. Two approaches work:

Option A (Recommended): Create a dedicated OBS scene built at 1080×1920 — position your camera feed, overlays, and graphics vertically within that scene. In the obs-multi-rtmp panel, assign this vertical scene as the source for your YouTube output only. Your main OBS canvas stays at 1920×1080 for Twitch. OBS encodes the correct format for each platform simultaneously.

Option B (Advanced): Run a second OBS instance configured entirely in 1080×1920, fed by a virtual camera from your primary OBS session. This produces fully independent scenes for each platform but carries a significant CPU and memory overhead.

Note: Option A is the right choice for most setups. It keeps everything inside a single OBS session, avoids the performance hit of dual encoder instances, and is far simpler to troubleshoot if something goes wrong mid-stream.

Stream Settings to Optimize for Both Platforms

These are the encoder settings that determine quality on both destinations. Because the two streams share your available upload bandwidth, the numbers need to reflect what your connection can actually sustain.

Upload speed math: Both streams at 6,000 Kbps each = 12 Mbps of video bandwidth. Add audio and protocol overhead and you need a reliable 15 Mbps upload minimum — 20+ Mbps is the comfortable operating margin. If your connection falls short, reduce Twitch to 4,500 Kbps and YouTube to 3,500 Kbps. The quality drop in both directions is modest; a dropped stream isn’t.

Encoder choice: Use your GPU’s hardware encoder (NVENC for Nvidia, AMF for AMD, VideoToolbox on Mac) over x264 software encoding wherever possible. Hardware encoding cuts CPU load substantially when running two parallel encoder outputs.

Audio: Clean audio matters equally on both platforms. A wireless clip-on mic like the Hollyland LARK M2 eliminates cable clutter in a dual-platform streaming setup and delivers consistent audio to both destinations without any additional routing or configuration on your end.

Common Issues and Quick Fixes

YouTube stream isn’t appearing as a Short. Confirm the signal actually reaching YouTube’s ingest server is vertical — not just your OBS canvas setting, but the encoded output being transmitted. Also verify the stream is set to Public in YouTube Studio; private or unlisted live streams may not be classified or surfaced as Shorts regardless of aspect ratio.

One platform drops while the other stays live. This is almost always a bandwidth problem. Your upload speed can’t sustain both output bitrates simultaneously. Reduce each stream’s bitrate by 1,000–1,500 Kbps, and close any background applications or other uploads competing for bandwidth during the stream.

Stream key rejected at the platform level. Regenerate the key directly: YouTube Studio → Go Live → Stream → Reset Stream Key; Twitch → Creator Dashboard → Settings → Stream → Reset Key. Update the new key in Restream or your obs-multi-rtmp panel before attempting to go live again — old keys are invalidated immediately on reset.

FAQ

Can I multistream to YouTube Shorts and Twitch for free?

Yes. OBS Studio with the obs-multi-rtmp plugin is completely free and supports simultaneous output to both platforms with independent settings per destination. Restream and StreamYard both have free tiers, but those plans typically restrict multistreaming to a single destination at a time — simultaneous dual-platform output requires a paid subscription on either service.

Does YouTube count a live stream as a Short automatically?

YouTube classifies a live stream as Shorts-eligible when the source signal is vertical (9:16). A long vertical live stream will appear on your Shorts shelf after the broadcast ends, but Shorts promotion isn’t guaranteed unless the replayed or clipped version is 60 seconds or under. The stream duration can be longer — the vertical format is what triggers Shorts classification, not the stream length itself.

Does multistreaming lower video quality?

It can, if your upload bandwidth is insufficient. Both streams share your available upload speed, so running full bitrate on both simultaneously can cause one or both to degrade or drop. Either reduce per-destination bitrate to a level your connection can sustain, or ensure your connection supports at least 15–20 Mbps clean upload before going live.

Do I need separate content for YouTube Shorts and Twitch?

Not during the live broadcast — multistreaming sends identical content to both platforms simultaneously. Post-stream, YouTube may surface your vertical content on the Shorts shelf while your Twitch VOD remains in horizontal format. Building your stream layout with both orientations in mind from the start helps replayed content look intentional on each platform rather than cropped or letterboxed awkwardly.

Which multistreaming tool works best for YouTube Shorts specifically?

Restream.io is currently the most reliable managed option for Shorts, offering per-destination output settings and handling the platform routing through its dashboard. For a cost-free setup with full technical control, OBS Studio with the obs-multi-rtmp plugin and a dedicated vertical scene is the strongest alternative — though it requires more initial configuration to get right.

What to Do Next

For most creators, Restream.io is the fastest path to a working dual-platform stream with the least configuration friction. If keeping costs at zero matters more, the OBS + obs-multi-rtmp plugin method gets you there without a subscription — just budget extra time for the vertical scene setup.

Either way, the vertical format configuration for YouTube Shorts is the step most people skip, and skipping it is the most common reason streams reach YouTube as standard horizontal videos instead of Shorts. Get that output set to 1080×1920 before you go live, and the rest of the setup is straightforward.

Suggested next reads: - How to Set Up YouTube Live Streaming from OBS Studio - Twitch Stream Settings Guide: Bitrate, Resolution, and Encoder - How to Install and Configure the obs-multi-rtmp Plugin