Using OBS Studio as a Commentary System

A Dr. NDI Tutorial

Recently, I was involved in a live sports video production where I needed to set up a commentary station. It was nothing unusual, as I have used many Dante commentary stations in my NDI productions. However, this time, I wanted to find a solution where a single device could offer the audio functionality of a commentary station and receive video feedback from the production, thus avoiding connecting two devices with two network cables.

I created this project using a small Windows computer and OBS Studio. In this tutorial, I will explain how to create your own NDI commentary station with these simple tools.

What you need to complete this project:

Hardware

• A Windows computer. I used the LattePanda 3 Delta.

  • https://www.lattepanda.com/lattepanda-3-delta. This computer is compact, powerful, and very affordable.

• An audio interface with Side Tone functionality.

  • This feature is essential in a commentary station, as it allows the commentator to hear themselves without delay, helping them avoid straining their voice in a noisy environment. I used the Focusrite Vocaster Two audio interface.

  • https://focusrite.com/products/vocaster-two

• A control surface to manage the commentary station functions. The Elgato Stream Deck is a great choice.

  • https://www.elgato.com/it/en/p/stream-deck-plus-black

Software:

OBS Studio and the following plugins:

• Distro AV for NDI support

• OBS Mute Filter

• OBS-Asio

Typical functions of a commentary station include:

• Transmitting the commentator's microphone signal to the production

• Sending and receiving talkback audio for coordination between the commentator and production

• Receiving and displaying the program video feed from the production with specific audio (usually international audio or an N-1 mix)

Step-by-step guide to setting up your commentary station:

Step 1

Install the drivers for your audio interface on your Windows computer. ASIO driver support is preferable.

Step 2

Install NDI Tools.

Step 3

Download and install OBS Studio from this link: https://obsproject.com/

After the installation, OBS will prompt you with some options

No specific selections are necessary as we will not be streaming or recording. You can click Cancel and proceed.

Step 4

Set the video format in OBS to match the video production format, which in my case is 1080 P50.

Go to Settings and then Video.

Step 5

Download and install the necessary plugins:

• Distro AV to add NDI support to OBS Studio - https://github.com/DistroAV/DistroAV/releases/download/6.0.0/distroav-6.0.0-windows-x64-Installer.exe
• ASIO drivers support for OBS - https://github.com/Andersama/obs-asio/releases/download/v3.2.1f/obs-asio-3.2.1-windows-x64-Installer.exe
• OBS Mute Filter - https://github.com/norihiro/obs-mute-filter/releases/download/0.3.0/obs-mute-filter-0.3.0-obs27-Windows.zip

This plugin doesn’t have an installer, so you’ll need to install it manually in OBS Studio by following the developer’s instructions. - https://github.com/norihiro/obs-color-monitor/wiki/Install-Windows

Step 6

Now that OBS Studio and the plugins are installed, configure the commentary station:

• Create the audio channel for live commentary:

• Select Asio Input Capture as the source and rename it to MIC-LIVE. Configure this source by selecting the Focusrite USB Audio in MONO mode with the Host Microphone as OBS Channel 1. Then, close the source panel.

• Set up the talkback channel:

  • Select Asio Input Capture again and rename it to MIC-TALKBACK. Configure this input the same way as MIC-LIVE.

• Add the intercom (talkback) audio channel from the production:

  • Select NDI® Source as the source and rename it INTERCOM. In the configuration panel, select the NDI source the director or production team will use to communicate with the commentator. In my case, this source is generated by a computer named PRODUCTION-PC, and the NDI stream is called TALKBACK_TO_COMM.

• Add the NDI feed the commentator will view, called PGM_MIX_MINUS, also generated by PRODUCTION-PC.

Step 7

Organize the audio workflow:

• Select the MIC-LIVE source and click on Filters.

Add the following filters:

• Discard Audio by UI

• Dedicated NDI® output (Audio Only)

Configure the NDI stream as MIC-LIVE.

• Repeat for MIC-TALKBACK, naming this stream MIC-TALKBACK.

• The Discard Audio by UI plugin lets users control the audio channel to broadcast commentary or talk with production. It ensures that muting the audio channel in the mixer also mutes the NDI output.

Step 8

Route the PGM and INTERCOM NDI sources to the commentator’s headphones:

• Ensure the Windows audio interface is the same as used in OBS.

• In OBS Audio Mixer, under Advanced Audio Properties, enable monitoring for the PGM and INTERCOM channels.

Step 9

Customize the OBS Studio interface:

• In the Docks menu, disable Scenes, Sources, Scene Transitions, and Controls.

• Hide the Desktop Audio source in the audio mixer as it’s not needed.

Then, move the audio mixer to one side of the interface. Changing the layout direction gives more space to the preview window showing the PGM return feed.

Step 10

Set up and configure the Stream Deck and OBS Studio plugin to manage the LIVE, TALKBACK channels, and PGM and INTERCOM levels.

• Create a TALKBACK button that mutes MIC-LIVE and enables MIC-TALKBACK, using the Multi Action Switch function.

First action disables MIC-LIVE and enables MIC-TALKBACK, and the second reverses the process.

• Add a Push to Mute button for the MIC-LIVE channel for a cough button.

• Add a toggle mute button for MIC-LIVE.

• Use two rotary controls to adjust the PGM and INTERCOM channel volumes.

And that’s it! You now have a fully functional commentary station with NDI.

Stay tuned, in the following tutorial, I’ll explain how to create a simple Intercom using OBS Studio, a real software gem!