Mobile SRT to vMix: use Larix as a remote phone camera

Before you configure the mobile stream, keep two signals in mind: incoming bitrate and network RTT. Bitrate shows whether media is arriving. RTT shows how much timing pressure exists on the path. Mobile networks can change quickly, so an SRT latency value that works in one place may be too aggressive in another.

Step 1. Create an SRT server in Callaba

Open Callaba and go to SRT Servers. Click Add New.

Create a new SRT server for the mobile phone stream.

• Name: use a clear name, for example mobile-larix-camera.
• Port: choose the publisher port that Larix will use to send the stream.
• Receiver port: choose the port that vMix will use to receive the stream from Callaba.
• Latency: use a realistic value for the mobile network. Do not start with the lowest possible value.

Save the server and open the server details.

You will need two values:

• Publisher URL: use this in Larix to send the mobile stream to Callaba.
• Receiver URL: use this in vMix to receive the stream from Callaba.

The important rule is simple: Larix uses the Publisher URL. vMix uses the Receiver URL.

Step 2. Set up Larix on the mobile phone

Open Larix on your phone and add a new connection.

Use the Publisher URL from Callaba as the destination.

• URL: paste the Callaba SRT Publisher URL.
• SRT mode: use caller mode if Larix connects to the Callaba SRT listener.
• Latency: match the value you selected for the SRT path.
• Stream ID: use the publisher stream ID from Callaba if your workflow requires it.

Then check the video and audio settings in Larix.

• Choose a bitrate your mobile network can hold consistently.
• Use a practical resolution, such as 720p or 1080p, depending on the connection.
• Make sure microphone or device audio is enabled if you need audio.
• Test the stream before the real production.

Start streaming from Larix. The mobile stream should now be sent to Callaba.

Step 3. Check the mobile SRT stream in Callaba

Go back to the SRT Servers section in Callaba.

Check whether the stream is arriving.

• Incoming bitrate: confirms that Larix is sending media.
• Connection state: confirms that the SRT session is active.
• RTT: shows timing pressure on the mobile path.
• Packet loss and retransmissions: show whether SRT is recovering from network problems.

If Callaba does not show incoming bitrate, check the Publisher URL, UDP port, SRT mode, Stream ID, passphrase, and mobile network connection.

Step 4. Receive the mobile SRT stream in vMix

Open vMix and click Add Input.

Choose Stream / SRT.

Use the Receiver URL from Callaba. A typical SRT receiver URL looks like this:

srt://12.34.56.78:1935?streamid=output/mobile-larix-camera/srt-stream-01

In vMix, you may need to split that URL into separate fields:

• Hostname: the Callaba server IP address or hostname.
• Port: the receiver port from Callaba.
• Stream ID: the value after streamid=.

Set the stream type to SRT Caller if vMix connects to the Callaba receiver endpoint.

Click OK.

A new input will be added to vMix. If all parameters are configured correctly, your mobile SRT stream should appear in a few seconds.

Step 5. Send the mobile input to the vMix master output

After the mobile SRT input appears in vMix, check audio routing.

Adjust the sound so this input can be sent to the Master output when needed.

You can now use your mobile phone as a vMix camera from anywhere with a stable enough network connection.

Optional: add Larix Talkback from vMix to the phone

In some productions, the remote camera operator needs to hear the director or the studio. This is where Larix Talkback is useful.

Talkback is a return audio path from vMix back to Larix. In practice, it is another SRT stream going in the opposite direction:

vMix audio bus → Callaba SRT server → Larix Talkback

This is useful for:

• communication between the director and the remote camera operator
• giving instructions during a live broadcast
• letting a remote correspondent hear the studio presenter
• sending IFB-style audio to the phone

Step 6. Enable an audio bus in vMix

vMix uses audio buses such as A, B, C, D, and Master to send audio to different outputs.

For talkback, use a separate bus so the director’s microphone can be sent to the remote phone without going to the public program output.

First, check that Bus A is enabled:

Settings → Audio Outputs → A: Enabled → OK

You may need to restart vMix after changing audio output configuration. Your preset should remain saved.

Step 7. Add the director microphone in vMix

In vMix, click Add Input, choose Audio Input, and select the microphone connected to your production machine.

Configure the microphone routing:

• Turn off Master if the director’s voice should not be heard by viewers.
• Enable Bus A so the microphone can be sent to Larix as talkback.

You can also send other vMix inputs to Bus A if the remote operator needs to hear program audio or studio audio.

Step 8. Create a second SRT server in Callaba for talkback

To send talkback from vMix to Larix, create a second SRT server in Callaba.

This server should be separate from the mobile video ingest server.

• Name: use a clear name, for example mobile-talkback.
• Port: use a different port, for example 1936.
• Latency: choose a practical value for the return audio path.

Click Save.

Open the Info window for the new SRT server. You will use these parameters to send audio from vMix to Larix.

Step 9. Send talkback audio from vMix over SRT

Open vMix and go to:

Settings → Outputs / NDI / SRT

For talkback, use Output 2 or another output that is not already used for the main program feed.

Click the gear icon to open the output settings.

Configure the output:

• Audio Channels: Bus A.
• Enable SRT: On.
• Type: Caller.
• Latency: use your selected value, for example 120 ms.
• Hostname: Callaba server IP address or hostname.
• Port: the talkback SRT server port, for example 1936.
• Stream ID: the publisher stream ID of your talkback SRT server, for example input/talkback/srt-stream-01.

Save the output settings.

Step 10. Configure Larix Talkback

Now configure Larix on the mobile phone to receive the talkback audio from Callaba.

In Larix, go to:

Settings → Talkback → +

Create a new talkback connection:

• Name: use a clear name, for example Director talkback.
• URL: use the SRT address of your Callaba talkback server.
• SRT receiver mode: Caller.
• Latency: use the value selected for the talkback path.
• Stream ID: use the receiver stream ID of your talkback SRT server, for example output/talkback/srt-stream-01.

Click Save.

Make sure there is a check mark next to the new connection and return to camera mode.

If the status shows talkback ONLINE, the connection is working. The remote operator should now hear the audio from vMix Bus A on the mobile device.

What to check if mobile SRT does not appear in vMix

• Wrong URL: Larix must use the Callaba Publisher URL. vMix must use the Callaba Receiver URL.
• Wrong port: check publisher and receiver ports in Callaba.
• Blocked UDP: SRT uses UDP, so the required ports must be open.
• Wrong Stream ID: copy the Stream ID exactly as shown in Callaba.
• No incoming bitrate: check whether Larix is actually sending to Callaba.
• vMix input mode: confirm that vMix uses the correct SRT caller/listener mode.
• Mobile network instability: lower bitrate or increase SRT latency.
• Audio routing: check whether the vMix input is routed to Master or the correct audio bus.

Common problems and fixes

Larix is streaming, but Callaba shows no bitrate

Check the Publisher URL, SRT mode, Stream ID, passphrase, UDP port, and mobile internet connection. Make sure Larix is sending to the Callaba ingest endpoint, not to the receiver endpoint.

Callaba receives the stream, but vMix shows nothing

Check the Receiver URL, hostname, port, Stream ID, and vMix SRT input mode. Also confirm that the Callaba stream has an active receiver-side output available for vMix.

The mobile stream is unstable

Reduce bitrate, lower resolution, avoid weak Wi-Fi, check mobile signal, and increase SRT latency if needed. Mobile networks can change during a live event, so test the path before production.

There is video but no audio in vMix

Check Larix audio settings, phone microphone permissions, audio codec, and vMix input audio routing. Make sure the input is not muted and can be sent to Master when needed.

Talkback is online, but the operator hears nothing

Check vMix Bus A routing, director microphone input, SRT talkback server, Larix Talkback connection, phone volume, and headset output. Make sure the director microphone is routed to Bus A but not necessarily to Master.

The audience hears the director’s talkback microphone

Turn off Master routing for the director microphone input. Send it only to Bus A or the audio bus used for talkback.

When this workflow is useful

This mobile SRT to vMix workflow is useful when you need a remote phone camera inside a live production, but you do not want the phone to stream directly to the final platform.

Use it when you need:

• a remote phone camera in vMix
• a cloud ingest point between phone and studio
• monitoring before the feed enters production
• recording or restreaming of the same mobile feed
• talkback from the director to the mobile operator
• a cleaner production workflow than direct phone-to-vMix networking

FAQ

Can I send SRT from a mobile phone to vMix?

Yes. You can send SRT from a mobile phone using Larix, receive the stream in Callaba, and then bring it into vMix as an SRT input. This lets you use the phone as a remote camera in a vMix production.

What is SRT mobile streaming?

SRT mobile streaming means sending live video from a phone over the SRT protocol. It is useful when a phone needs to act as a remote contribution camera for a production system such as vMix.

Do I need Callaba between Larix and vMix?

You do not always need Callaba, but it makes the workflow easier to control. Callaba becomes the SRT ingest point, shows stream status, and gives vMix a receiver-side URL. It can also record, restream, or route the same mobile feed.

Which URL should Larix use?

Larix should use the Callaba SRT Publisher URL. This is the URL used to send the mobile stream into Callaba.

Which URL should vMix use?

vMix should use the Callaba SRT Receiver URL. This is the URL used to receive the mobile stream from Callaba into vMix.

Can I use a mobile phone as a vMix camera?

Yes. With Larix, Callaba, and vMix, a mobile phone can work as a remote camera. The phone sends SRT to Callaba, and vMix receives the feed as an SRT input.

Does vMix support SRT input?

Yes. vMix supports SRT input and output workflows. You can add an incoming SRT stream through Stream / SRT and use it as a normal vMix input.

What is Larix Talkback?

Larix Talkback is a return audio workflow. It lets the remote mobile operator hear audio from the studio or director. In this setup, vMix sends talkback audio through Callaba to Larix over SRT.

Why is my mobile SRT stream unstable?

Mobile SRT streams can be unstable because of weak signal, changing upload speed, Wi-Fi problems, high bitrate, overheating, or too low SRT latency. Lower the bitrate, choose a practical resolution, and increase latency if the network needs more recovery time.

Can I record the mobile SRT stream?

Yes. After Callaba receives the mobile SRT stream, you can use it as an input for recording, restreaming, routing, or playback workflows.

Next steps

• Sending and receiving SRT stream via vMix
• What is an SRT server?
• What is SRT protocol?
• Find the perfect latency for your SRT setup
• SRT vs RTMP
• Multi-streaming with Callaba
• Continuous streaming with Callaba