Castr can forward your video to YouTube, but it does not create YouTube’s vertical viewing layout. To reach viewers in portrait, choose YouTube’s vertical layout or configure an encoder to send a separate portrait feed using the correct vertical stream key before you go live.
The distinction matters because the distribution route and the viewer’s layout are separate settings. You set up the source and YouTube destination in Castr, then confirm the vertical presentation and stream settings in YouTube Live Control Room.
Castr sends the feed; YouTube controls the layout
Think of the workflow as two connected jobs. Castr receives a source and forwards it to destinations you configure; YouTube determines how the live video is presented to viewers and which stream settings apply. Castr’s stream setup guide describes creating a stream, selecting a source method and adding a destination. YouTube’s vertical live stream help explains its vertical layout and dual-stream options.
For a single horizontal source, YouTube can adapt the picture for a vertical viewing experience using its layout controls. For a production that needs distinct horizontal and portrait compositions, an encoder can send the matching feeds to their respective YouTube stream keys. These are different workflows: the first relies on YouTube’s layout, while the second gives your production setup responsibility for the portrait composition.
Castr is useful when the source should reach YouTube through a configured distribution workflow, rather than relying on a computer to stay on and send directly for the duration of the broadcast. The portrait framing still needs to be decided on the YouTube or encoder side. If you are preparing a recorded programme rather than a live camera or encoder source, the planning principles in this guide to a looping YouTube Live video may help you think through the content and continuity separately from portrait layout.
Create a Castr stream and select its source
Sign in to Castr and create a live stream. Castr’s setup instructions describe choosing a hosting region and then setting the source. The interface may change, so follow the labels in your current dashboard rather than assuming every screen is identical to a guide written earlier.
Choose the source method that matches how you are producing the programme. Castr documents RTMP or RTMPS publishing and a webcam option. Its multistream guidance also describes an encoder sending a feed to Castr using RTMP or SRT. A webcam is a straightforward fit for a simple live presentation; an encoder is more appropriate if you need controlled scenes, graphics or separately composed video formats.
Before moving on, establish what the source actually contains. A horizontal camera or file is not automatically a carefully composed portrait programme. If you intend to use YouTube’s built-in layout, check that the important part of the image will survive the crop or fit treatment. If you intend to supply a separate portrait version, prepare that composition at the production stage and know which feed your encoder will send.
Keep the source and destination roles clear while setting up. Castr’s source is what it receives; YouTube is a destination to which Castr forwards the stream. If you have previously configured an encoder for a direct YouTube broadcast, do not assume its old destination arrangement also maps correctly through Castr. Confirm where the encoder publishes and which output is routed to each platform key.
Add YouTube as a destination
In the Castr stream’s destination settings, add YouTube. Depending on the current dashboard and the connection method you choose, you can connect a YouTube account or provide the platform’s server and stream key details. Complete any requested platform fields, save the destination and switch it on. Castr’s destination workflow is covered in its multistream guide; check the current dashboard for available options and account-specific limits.
An account connection and a server-and-key connection are ways of authorising or directing the feed, not ways of choosing portrait layout. Whichever method you use, verify that the destination belongs to the intended YouTube channel and that you have selected the correct live event or stream in YouTube Studio. Avoid copying a key from an unrelated broadcast or an old setup without checking its purpose.
If your plan involves a portrait stream key as well as a horizontal one, pause before enabling the destination and map the routes on paper. Write down which encoder output carries horizontal video, which carries portrait video, and which YouTube key each output must reach. Castr documents destination forwarding, but the available research does not establish that every account or dashboard arrangement automatically maps two encoder feeds to two distinct YouTube keys. Confirm your specific route in the Castr interface before relying on it for a broadcast.
Once the YouTube destination is configured, make sure it is enabled. A saved destination that remains off will not receive the feed. Then open YouTube Live Control Room separately to inspect the stream and its presentation settings; adding a destination in Castr does not complete that part of the setup.
Choose YouTube’s vertical layout or dual-stream path
YouTube offers two relevant approaches. Its built-in dual stream can create horizontal 16:9 and vertical 9:16 viewing formats at the same time through Live Control Room. Alternatively, an encoder can supply horizontal and portrait feeds, with each format sent to its corresponding stream key. YouTube’s instructions for streaming in horizontal and vertical formats describe both paths.
| Approach | Who shapes the portrait picture | What you need to configure | Main trade-off |
|---|---|---|---|
| YouTube built-in dual stream | YouTube’s layout controls adapt the source | Select the built-in approach and inspect the vertical preview | Less production routing; framing depends on the chosen layout and source composition |
| Encoder-supplied dual stream | Your production encoder creates the portrait feed | Configure both formats and send each to its matching YouTube key | More control of the portrait composition, with more routing and preflight work |
With YouTube’s built-in approach, the vertical composition can use a centre crop, fit to phone width or stacked layout. The default centre crop may be suitable when the subject stays near the centre, but it can cut off captions, instruments or people arranged towards the edges. Fit to phone width and stacked presentation handle the source differently, so judge the actual preview rather than choosing by name alone. You can adjust zoom and position where the controls allow it.
With an encoder-supplied approach, the encoder creates the portrait image instead of asking YouTube’s layout to make it from a single horizontal feed. That can matter for a devotional programme with a centred singer and text, a local news presentation with a presenter and ticker, or a lofi scene composed specifically for a phone screen. It also means someone must verify that the encoder’s portrait output reaches the vertical key, while the horizontal output reaches the horizontal key.
Neither route is universally better. If a single source and YouTube’s available layout produce a clear portrait image, the built-in route has fewer separate feeds to manage. If the picture needs intentional portrait framing, a separately produced feed offers control, but adds a key and route that must be tested. Choose on the basis of the image your viewers should see and the routing you can reliably operate.
Configure the portrait feed and stream key before going live
For the built-in dual-stream path, select it in Live Control Room and inspect the vertical preview before starting the broadcast. Choose the composition that keeps essential material visible. If a lower-third, lyric line or face disappears in the preview, correct the layout or source framing now rather than expecting Castr to repair the composition later.
For the encoder path, open the Stream tab in YouTube Live Control Room and select the encoder option for the vertical preview. YouTube’s instructions describe using RTMP(S) and a second stream key for the vertical feed. Keep the mapping explicit: the portrait encoder output goes to the vertical key, and the horizontal output goes to its corresponding key. Then confirm that the Castr destination arrangement and encoder publishing method actually deliver those feeds to the intended YouTube inputs.
A stream key is a routing credential, not a format switch. Sending a horizontal feed to the vertical key does not make it a well-composed portrait programme. Similarly, selecting a vertical layout in YouTube does not mean a second encoder output is configured. Check both the picture and the destination settings in preview.
Complete this configuration before you start. YouTube states that vertical format cannot be added once a stream has started. If you discover after going live that the vertical format is missing or the wrong key was used, do not assume there is a setting to add it to that active stream. Correct the setup for a later start and consult YouTube’s current Live Control Room guidance before changing the live event.
Treat a key as private account information. Use the key shown for the intended stream, do not put it in public notes or a public scene, and confirm the channel and event before publishing. If more than one person is helping with the broadcast, give them a route map that identifies outputs by format without circulating the key more widely than necessary.
Verify the destination and layout in YouTube
Before the scheduled start, open YouTube Studio’s Live Control Room and confirm that the intended event is selected. Check the incoming preview, the vertical preview if using that path, and the stream’s destination state in Castr. The key question is not simply whether Castr says it is forwarding; it is whether YouTube is receiving the intended picture in the intended format.
Look for practical framing problems. Is the face or main subject visible on a phone-shaped screen? Are lyrics, captions or news graphics legible and inside the safe area? If the video uses stacked layout, does each part of the picture remain understandable at the size a mobile viewer will see? Check motion too: a crop that looks acceptable on a still frame may lose a moving subject when it crosses the frame.
Also check how the format affects the viewer experience. YouTube says vertical live streams can be discovered in the Shorts browsing experience and shown full-screen in the YouTube mobile app. That is a possible viewing context, not a promise that YouTube will recommend or surface any particular stream. The vertical live feed is not available on tablets, and scheduled live streams and Premieres do not appear in that feed according to YouTube’s current help page. Check current YouTube guidance if those details matter to your event.
Some features differ between vertical and horizontal viewing. YouTube’s feature information distinguishes such items as clickable links in chat or channel description, certain ad formats, 4K broadcast bitrate, Premieres and Live Redirect for horizontal from the vertical feed. Feature availability can change and may depend on channel eligibility, so check YouTube Studio rather than building a programme around an assumption. If you are considering how a handoff between streams works, first review the constraints in this guide to YouTube Live Redirect.
Test the complete route before the broadcast
Run a test before an event that matters. YouTube recommends preparing encoder streams ahead of time, checking the Live Control Room preview and monitoring audio and video. You can use an unlisted test stream to inspect the experience without making the test a public programme. Follow YouTube’s live streaming tips for current preparation advice.
Test the route end to end, not just the encoder’s local preview. Start the source, confirm Castr receives it, confirm the YouTube destination is enabled, then inspect what arrives in Live Control Room. If you are sending two formats, verify both pictures and their matching keys independently. A correct horizontal preview does not prove that the portrait feed is routed correctly.
Listen with headphones and check the programme from a viewer’s perspective. Confirm the microphone or programme audio is present, that music is not unexpectedly absent, and that speech is not masked. Watch the portrait preview for crop changes, dropped graphics or text that sits too close to the edge. If the stream is coming from a mobile device, YouTube’s mobile guidance recommends locking screen rotation and testing network conditions, audio and video; an external battery pack is an option rather than a prerequisite.
Write down what passed and what needs attention, then repeat the test after changing a key, layout, encoder profile or Castr destination. A test is especially useful when the workflow crosses several controls: source, encoder, Castr, YouTube destination and vertical layout. For encoder-based workflows, a guide to SRT ingest for YouTube Live can help you understand one of the source transport choices, but it does not replace checking the separate YouTube portrait routing.
For a channel that must keep running when your own computer is switched off, decide separately how the programme will be operated and monitored. StreamNeo turns an uploaded video into a YouTube live stream and removes the need to leave your own computer running for that file-based broadcast; it does not choose YouTube’s vertical layout or remove the need to verify the portrait stream settings.
If you are ready to evaluate an operating approach after confirming the YouTube workflow, compare the operating options on the pricing page. When the file and channel are ready, start free — 24-hour trial, no card.
Before committing, compare the operating options on the pricing page. When the file and channel are ready, start free — 24-hour trial, no card.
FAQ
How do I stream vertically to YouTube with Castr?
Create a stream in Castr, select the source method, add YouTube as a destination and enable it. Then choose YouTube’s built-in vertical layout or configure an encoder to send the portrait feed to the correct vertical stream key before the broadcast starts.
Can Castr create YouTube’s vertical layout?
Castr distributes a source to configured destinations; YouTube’s Live Control Room controls its vertical layout and stream settings. If you want a distinct portrait composition, arrange for your encoder to produce that feed and verify the destination routing.
Can I add vertical format after a YouTube stream starts?
No. YouTube says you cannot add vertical format after the stream has started. Configure the built-in layout or encoder-based dual stream, and check the preview and stream keys before going live.
Should I use YouTube’s layout or an encoder-supplied portrait feed?
Use YouTube’s built-in layout when its preview frames your single source well and you want fewer feeds to route. Use a separately produced portrait feed when you need deliberate control of the mobile composition and can test the second key and routing in advance.