Larix Broadcaster to vMix over SRT: Setup Guide | Callaba
More live video workflow notes and product updates.
Use a phone as a field camera without losing the production handoff
Larix Broadcaster can send SRT from iOS or Android. Callaba gives that mobile contribution a known entry point, transport visibility and a route into vMix. Optional Talkback returns director audio to the phone.
The result is useful only after the whole loop has been tested on the networks the operator and camera will actually use.
Prepare the field kit before creating URLs
On the phone
Install the current Larix Broadcaster release, permit camera and microphone access, keep power available, disable notifications that can interrupt capture, and confirm whether cellular data switching is allowed.
At production
Prepare Callaba, vMix, a monitored audio return, a person who can speak to the camera operator, and an alternate way to communicate if Talkback fails.
On the network
Use the public host and UDP port assigned to the SRT Listener. Verify firewall policy and test from outside the studio network.
In the runbook
Record the endpoint role, latency, passphrase policy, codec, expected bitrate, phone orientation and recovery action without exposing secrets.
Create the mobile contribution path
- Callaba
- Create an SRT server with a Listener entry for the phone. Start it and copy the publisher connection details. Keep access limited to the intended source.
- Larix
- Add a new connection, choose SRT and enter the Callaba host, port and parameters. In the common pattern Larix is Push/Caller and Callaba waits as Listener.
- First proof
- Start Larix. Confirm Callaba shows the session and incoming bitrate, then open the feed in Multiview. Check camera orientation, program audio and sustained encoding.
- vMix
- Add the Callaba receiver URL using the matching SRT role and input type. The exact vMix dialog can change by version, so preserve the working configuration with the production file.
- Rehearsal
- Walk through the expected coverage area, move between realistic network conditions, rotate only if the production permits it, and test a deliberate reconnect.
Softvelum’s current SRT product reference confirms Larix Broadcaster support for Push/Caller, Listener and Rendezvous modes. Use that page when app labels or available parameters change.
Add Talkback as a separate return path
Talkback does not ride automatically inside the camera feed. In Larix, open Talkback and add an incoming return-audio connection. Softvelum documents SRT Pull, Listen and Rendezvous inputs, as well as supported AAC and Opus combinations.
Choose headphones on the phone to prevent the director feed from returning into the program microphone. Test level, delay and reconnection independently from the outbound camera.
Use Softvelum’s official Larix Talkback guide for the current app path and supported input modes.
Accept the path with three proofs
Transport
Session state, bitrate, RTT and recovery behavior remain understandable during movement.
Production
vMix receives stable picture and program audio with the intended delay and format.
Operator loop
The phone hears Talkback without echo, and the crew knows what to do after a disconnect.
Do not promise what one successful rehearsal cannot prove
A phone contribution path depends on battery, thermals, radio conditions, carrier policy and the human holding the camera. One clean test is not a reliability guarantee. For higher-stakes events, prepare a second network or source and use Callaba monitoring and recording to make the operating state visible.
Review Callaba SRT Server for access, live statistics and recovery options. If the path breaks only under changing networks, use the measured latency tuning guide.