IRL Pro and Moblin Setup: Connect Your Phone to an SRTLA Server
October 09, 2026 · 10 min read
Table of Contents
IRL Pro (Android) and Moblin (iPhone) are free streaming apps that can send your camera feed over SRT or SRTLA to your own server. In both apps you create a new connection, enter the server address together with the stream ID, and use srtla:// instead of srt:// if you want to bond several connections such as WiFi and mobile data.
Which app for which phone?
The decision is simple: Moblin runs on iPhone, IRL Pro runs on Android. Both are made for IRL streaming, both can send SRT and SRTLA, and both are free to install. Here is what the developers themselves state about the two apps.
| Moblin | IRL Pro | |
|---|---|---|
| Platform | iPhone, iPad and Mac, plus an Apple Watch companion app | Android (Google Play) |
| Price | Free, open source (MIT license). Optional purchases only for cosmetics such as app icons | Free on Google Play |
| Protocols | RTMP, RTMPS, SRT, SRTLA, RIST and WHIP | SRT and SRTLA bonding, plus Twitch, Kick, YouTube and any RTMP or SRT destination |
| Video codecs | H.264/AVC and H.265/HEVC, up to 4K and 60 FPS | Check the video settings of your app version |
| Bonding | One cellular, one WiFi and several Ethernet connections at the same time, with upload statistics and priorities per connection | SRTLA bonding over multiple connections |
| Adaptive bitrate | For SRT, SRTLA, RIST and RTMP | Auto bitrate algorithm and on-the-fly bitrate adjustment |
Sources: the Moblin repository on GitHub and the IRL Pro website. Both apps change regularly, so menu names can differ slightly from what you read here.
What you need from your server
For an SRT or SRTLA connection the app needs three things: the host (address of the server), the port and the stream ID. Many apps take them as one URL, for example srt://<server>:<port>?streamid=publish:publish/<streamkey>&latency=2000. For bonding, srtla:// replaces srt://. Moblin shows a similar example in its URL field.
The protocol in front of the address decides how the app sends:
- srt:// sends over one connection.
- srtla:// bonds several connections, but only works if the server accepts SRTLA input.
Our IRL Endpoint Server accepts RTMP, SRT and SRTLA input. After you order, you get access to the customer portal. There you pick a server region (USA, Europe, Asia or South America) and find a box with your RTMP and SRT credentials. On the standard plan you can switch the region at any time. For the app, take the server, port and stream key from the SRT data: the stream ID has the form publish:publish/<streamkey>, as in the example above, where <streamkey> is the key from the portal, not the one from Twitch or YouTube. We recommend a latency of 2 seconds, which is 2000 ms. You do not need an SRT passphrase. You do not have to open any ports on your router, because your phone and your streaming software at home both connect outbound to the server.
One thing is easy to get wrong: your Twitch or YouTube stream key does not go into the phone app. The phone sends to the server, and your streaming software such as OBS Studio pulls the stream from there and sends it to your platform. The stream key belongs into OBS.
Set up Moblin on the iPhone
- Install Moblin from the App Store. You do not need an account.
- Create a stream. Open Settings, then Streams, and tap the button to add a new stream. The setup wizard has an option for your own server, and a custom SRT(LA) option. Both ask for a URL.
- Enter the URL. Paste the server address and port from the SRT data in your portal, for example
srtla://<server>:<port>. The wizard also has a separate stream ID field. It replaces or adds the stream ID in the URL, so you can fill in either place. The stream ID has the form publish:publish/<streamkey>. - Open the SRT(LA) settings of the stream. Here you find latency, adaptive bitrate and connection priorities. The priorities only apply to SRTLA.
- Check the video settings: codec, resolution, FPS, bitrate and keyframe interval (2 seconds). With HEVC on the iPhone, turn off B-frames if the app offers the option. See the recommendations below.
- Activate the stream with the toggle in the stream list and start streaming from the main screen.
Moblin can also import settings from a moblin:// link, which some providers use to hand out ready-made configurations.
Set up IRL Pro on Android
IRL Pro does not publish a manual on its website. The steps below follow the menu names used in third-party setup guides, so check them against your app version.
- Install IRL Pro from Google Play.
- Open the settings with the gear icon, then Connections, then create a new (outgoing) connection.
- Enter name and address. Give the connection a name and enter your server address with protocol, host and port, for example
srtla://host:port. Depending on the version, protocol, host, port and stream ID are separate fields or one URL. - Enter the stream ID in the form publish:publish/<streamkey>, using the stream key from your portal.
- Set the SRT sender mode to Caller. Your phone connects to the server, not the other way round.
- Set the latency to 2 seconds (see below) and, if your version has the option, the keyframe interval to 2 seconds. Save and start the stream from the main screen.
Ignore the quick-setup buttons for Twitch or Kick when you stream to your own server. They are meant for sending directly to a platform.
Bonding with WiFi, mobile data and more connections
SRTLA is an extension of SRT. According to its documentation, it transports SRT traffic over multiple network links for more capacity and redundancy, and balances the traffic dynamically depending on the network conditions. The intended use is bonding mobile modems for live streaming. For this to work, the receiving server has to understand SRTLA.
- Moblin can use one cellular, one WiFi and several Ethernet connections simultaneously. In the SRT(LA) settings you can switch connections on or off and give each a priority from 1 to 10. A connection with high priority is used more, as long as it is stable. Unstable connections get the lowest priority until they recover. Moblin also shows upload statistics per connection, so you can see whether more than one is really in use.
- IRL Pro lists SRTLA bonding over multiple connections as a feature. Whether WiFi and mobile data are used at the same time depends on your phone and app version, so test it.
- Extra phones: the free companion app Moblink turns spare Android phones into additional connections for Moblin. Its developers recommend a different carrier on the spare phone and switching off battery saving so it stays awake.
A simple test before you go out: start the stream, then switch off WiFi or mobile data for a moment. With working bonding the picture keeps running. Keep in mind that bonding cannot help if all connections are weak at the same place. Two SIM cards from different carriers are more useful than two connections on the same network.
Recommended settings and why
There is no universal value that works everywhere. These are starting points based on the apps' own defaults and hints, which you adjust to your connection.
| Setting | Starting point | Why |
|---|---|---|
| Protocol | srtla:// with two or more connections, otherwise srt:// | SRTLA only helps if more than one connection is available and the server accepts it. |
| Codec | H.265/HEVC if your phone, the app and your streaming PC support it, otherwise H.264 | Moblin notes that HEVC generally needs less bandwidth for the same image quality. RTMP generally only carries H.264, SRT can carry HEVC. |
| Resolution and FPS | 1080p at 30 FPS (Moblin default). 60 FPS only with a stable, strong upload | More pixels and more frames need more bitrate. Moblin also notes that a lower FPS gives a brighter image in low light. Our server accepts up to 1080p at 60 fps. |
| Bitrate | Moblin suggests that about 5 to 8 Mbps is usually enough for decent quality. Stay below your stable upload | A bitrate above what the connection delivers causes drops. Also match it to the output bitrate in your streaming software. |
| Adaptive bitrate | On | The app lowers the bitrate when the connection gets worse instead of dropping frames. In Moblin, the BELABOX and Fast IRL algorithms are described as the safest options. |
| SRT latency | 2 seconds (2000 ms) recommended, higher on poor networks. Moblin's default is 3000 ms | Latency is the time SRT has to retransmit and reorder packets. We recommend 2 seconds deliberately in favor of stability, and lower values are possible. Some apps ask for microseconds, then enter 2000000. Moblin warns that its own SRT implementation does not perform well below 1000 ms. Switch to the Official implementation if you want low values. |
| App in foreground | Keep the app open and the screen on | In the background, Moblin can only send audio plus a frozen frame, because video cannot be captured there. |
Typical errors and how to fix them
| Problem | Likely cause | What to do |
|---|---|---|
| No connection at all | Typo or space in URL or stream ID, wrong port, wrong protocol, or the address meant for OBS was copied instead | Copy the values again from the portal and use the ones meant for the phone. Check the stream ID first. |
| Connects, but only one link is used | srt:// instead of srtla://, a connection is switched off, or WiFi or mobile data is disabled | Use srtla://, check the connection priorities in Moblin and test by switching links off one by one. |
| Picture is pixelated or choppy | Bitrate higher than the upload can carry | Lower bitrate or resolution, turn on adaptive bitrate, increase latency. |
| Frequent dropouts on a bad network | Latency too low to retransmit lost packets | Increase the latency step by step. In Moblin, avoid values below 1000 ms with the Moblin implementation. |
| Does not work over a spare Android phone's hotspot | Big packets | Switch off the Big packets option in the Moblin SRT(LA) settings. Its description says some Android hotspots do not work with it. |
| Cannot reach the server, although the URL is right | DNS lookup or IPv4/IPv6 handling on the network you are using | Try another DNS lookup strategy in the Moblin SRT(LA) settings, for example IPv4. |
| Video freezes when you switch apps | The app is in the background | Keep the streaming app in the foreground. |
Alternatives to IRL Pro and Moblin
Larix Broadcaster by Softvelum is a free mobile app for iOS and Android. Its product page lists SRT with the parameters latency, maxbw and streamid, as well as RTMP and other protocols. SRTLA bonding is not listed there, and HEVC is a premium feature. If you do not need bonding, it is an option on both platforms. If you prefer dedicated hardware over a phone app, encoders such as BELABOX or LiveU exist as well.
No PC at home? Then the IRL Broadcasting Server runs OBS Studio in the cloud and accepts the same RTMP, SRT and SRTLA input from your phone. For the big picture of IRL streaming, read our IRL streaming guide.
FAQ
Is IRL Pro free?
Yes. IRL Pro is listed as free on Google Play. Moblin is free as well. Its App Store page says all features are free and only cosmetics can be bought.
Is there an IRL Pro for iPhone?
IRL Pro is distributed through Google Play for Android. On iPhone, Moblin is the matching app and offers SRT and SRTLA bonding, too.
Do I need SRTLA, or is SRT enough?
SRT is enough if you stream from a place with one stable connection. SRTLA is worth it when you move around and have at least two connections, for example two SIM cards from different carriers. It only works if your server accepts SRTLA input.
Which bitrate should I use in IRL Pro and Moblin?
Moblin suggests that about 5 to 8 Mbps is usually enough for decent quality. Choose a value below your stable upload speed and match it to the output bitrate in your streaming software. Adaptive bitrate helps when the connection fluctuates.
Can I stream to Twitch directly instead of using a server?
Yes, both apps can send directly to platforms. The downside is that the stream on the platform is interrupted when your connection drops. With a server in between, the stream stays online on the platform for brief interruptions, because your streaming software keeps sending.