Connecting OBS Studio To Zoom

In this section we are going to first install OBS Studio, then we are going to install the obs-ndi plug-in, following this we will connect the webcam to OBS Studio, and finally we will connect OBS Studio to Zoom.

You will notice in the diagram above that I show a network between the obs-ndi plug-in and the NDI Virtual Input. This means that, in theory, OBS Studio and its obs-ndi plug-in could run on one PC while NDI Virtual Input and Zoom could run on another. I am proposing that they all run on the same PC, but that is not obligatory.

Installing OBS Studio

If you haven't already done so, download and install OBS Studio from the OBS Studio download page. During installation the default settings should be fine.

Once installation has finished, download and install the obs-ndi plug-in from the OBS-NDI Plug-in page. During installation the default settings should be fine.

I do not propose to give any kind of tutorial on OBS Studio; the following instructions tell you what to do rather than exactly how to do it. There are plenty of YouTube tutorials to help you.

Run OBS Studio and add a new Scene Collection named 'Church'. In the Scene Collection menu, ensure that it is selected.

In the Scenes window there should be a single entry named 'Scene'. Right click on it and rename it to 'Webcam Only'. We are going to configure this scene so that it uses nothing but the webcam's video and audio.

The Sources window should have no entries in it. Click on the + button at the bottom to add a source. In the pop-up menu select Video Capture Device and give it a name of 'Webcam Video'. In the Properties dialog select your webcam in the Device selection. Leave everything else as default and close the dialog. There should now be a single entry in the Sources window called 'Webcam Video'.

Add another source, this time select Audio Input Capture and give it a name of 'Webcam Audio'. In the Properties dialog select your webcam in the Device selection. Leave everything else as default and close the dialog. There should now be a second entry in the Sources window called 'Webcam Audio'.

In the Audio Mixer window there should be two entries, one for Webcam Audio and the other for Webcam Video. If you tap your webcam you should see the level change for the Webcam Audio but not for the Webcam Video. Click on the speaker icon for Webcam Video to mute that entry.

We are now going to setup the video so if you don't know what the default resolution of your webcam is, now would be a good time to find out. As always, Google is your friend if you have misplaced your documentation.

Let us say for the sake of argument that this resolution is 1280x720. I will use this value in the following steps. If your resolution is different just substitute yours for mine.

Click on the Settings button on the lower right hand side.

In the Output section set a path for any recordings that you may wish to make in the future. If you cannot change this because it is greyed out then you may have an output device active, by which I mean that in the Tools menu - NDI Output Settings one or more of the outputs is checked; or if VirtualCam is installed then it is started.

In the Audio section ensure that all entries in the Devices box are disabled. In the Advanced box select your normal loudspeaker device in the Monitoring Device drop down menu.

In the Video section set the Base (Canvas) Resolution to 1280x720, and the same for the Output (Scaled) Resolution.

Click on the OK button to close the Settings dialog.

In the Sources window right click on Webcam Video, select Transform from the menu and Fit To Screen from the sub-menu. The video should now fill the screen.

The webcam is now connected to OBS Studio.

Connect OBS Studio to Zoom

This section should more correctly be titled 'Connect the obs-ndi plugin to NDI Virtual Input' because that is exactly what we will be doing.

In the Tools menu select NDI Output Settings. In the dialog that opens set the Main Output name to 'OBS' and then check the Main Output box. Uncheck the Preview Output box, then click the OK button.

OBS Studio should now be broadcasting audio and video via NDI.

Right click on the NDI Virtual Input icon in the System Tray; a menu appears with the name of your PC at or near the top. Move your mouse pointer over the name of your PC; a sub-menu is displayed; select OBS. This has told NDI Virtual Input to listen for audio and video from the obs-ndi plug-in in your PC.

Now start a Zoom meeting. Zoom should remember its settings from last time which means that it should be displaying video and receiving audio from your webcam. If this is not the case then check that Zoom's audio source is Line (NewTek NDI Audio) and its video source is NewTek NDI Video.

You can check that audio is being received correctly by running the audio test in Audio Settings.

If the audio is too quiet you can adjust that in the Audio section of the NDI Virtual Input menu. I have found that I have to set mine to its maximum value (+20dB).

You have now setup the system to the point where it is very much as though you had your webcam directly connected to Zoom, which may seem like a lot of effort for no benefit. In actual fact it means that from this point forward things start to get interesting.

Time for another cup of tea and a break.

Why Use NDI? Why Not Use VirtualCam?

This is a very valid question and one that deserves an answer.

VirtualCam makes the main video output available to Zoom but not the main audio output. If it made the main audio output available then VirtualCam would be my preferred solution.

This then leaves the problem of making the audio available to Zoom.

OBS Studio offers no way of accessing its main audio output. It has a monitor output, which is normally connected to your speakers or headphone, which can be connected to a VB-Audio Virtual Cable input and the other end connected to Zoom. The problem is that you have now lost your monitoring, which means that if you want to play a video or audio file then you won't hear it through your speakers or headphone.

The obs-ndi plug-in captures the both main audio and video outputs and broadcasts them, which leaves the monitor output free for monitoring. At this point in time it is the best solution.


When I connect to a Zoom meeting, other participants tell me that my audio sounds like chipmunks!

It is said that if the sample rate of the audio device does not match that in Settings->Audio->General->Sample Rate then this effect will be produced. If you find that Settings->Audio->General->Sample Rate is greyed out then temporarily disable NDI Output and/or stop Virtual Camera./p>

I have been using a Logitech C600 webcam, which is a bit ancient. I have found that I can overcome this problem by changing the Device for the Webcam Audio source to a different input and then change it back to the webcam's mic then the problem does not occur.

I have now upgraded to a Logitech C920S webcam and the problem no longer seems to manifest itself. One difference is that, with this webcam, I have to use Logitech Capture software which seems somewhat more bloated than the previous applet that controlled the C600 webcam. Some things you just have to live with!

The audio level sent to Zoom is too quiet.

Right click on the NDI Virtual Input icon in the System Tray; select Audio in the menu that appears and then select +20dB. If this proves to be too loud then select a lower value.

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