Using OBS to Simulcast WebRTC and RTMP

You can share your real time stream using Millicast OBS and viewer while streaming to multiple destinations with RTMP and

Getting Started

Download the latest version of Millicast OBS WebRTC.

After you install Millicast OBS Web RTC install the multiple RTMP plug in.

obs-multi-rtmp is a plugin for streaming to multiple RTMP servers concurrently.

This plugin can share encoders with the main output of OBS to save CPU power. It can also use standalone encoders with basic configuration (bitrate).

How to Install the Plugin in Windows

  1. Download the latest release from OBS-Multi-RTMP.
  2. Unzip the zip file and extract it into the OBS folder.
    OBS Studio C:\Program Files\obs studio
    Millicast OBS default location. C:\Program Files\OBS WebRTC (64bit)\obs-plugins

You should see the following obs-multi-rtmp.dll in your plugins folder.


Once you have the obs-multi-rtmp.dll in your C:\Program Files\OBS WebRTC (64bit)\obs-plugins folder you can start OBS Millicast version.

When you open OBS now you will see the ability to add multiple RTMP targets.


Adding Stream Targets

  1. Your Real-time Streaming stream can be set up using the same using OBS guide.

Remember that you will need adequate bandwidth to stream to multiple destinations. To save bandwidth we are only going to send one additional stream to a free account. can then send your stream to multiple RTMP destinations.

  1. Now, let's set up the second stream target using the new stream target button.

The image is sending a 1080p stream at 6000kbps to and 3500kbps to Millicast real time viewer.

  1. In order to send the stream RTMP we will need to use the Audio settings option to encode the OPUS audio to AAC.

Start Publishing

If you do not have the stream sync to the start selected, you will need to select the start button on the multi-rtmp section.

Open your dash board and you should now see your stream as active.


The image shows OBS with Millicast viewer stream in sync. The stream will have added latency depending on the services selected.

MAC multi RTMP

The MAC version of the plug-in can be found here.

  1. For this set up download this ZIP and unpack it.
  2. Next select Applications>OBS WebRTC and show package content.
  3. Copy Multi RTMP plugin folder to your OBS WebRTC Plugin content folder.
  4. Next open the Multi RTMP bin folder and the copy the file to the root OBS plug-in folder.
  5. Restart OBS WebRTC and you can now add multiple RTMP targets.

This can also be used with RTMP Multi Bit rate option.