I’ve been experimenting with OBS NDI recently, and although it may not be as relevant in 2020 as it once was, I thought it best to take some notes on how to make a dual-PC streaming setup work before I forget. It’s pretty straightforward. Here’s what we need:
two computers on the same network (wired for best results)
two installations of OBS, one on either computer
the OBS-NDI plugin installed on both systems
I should mention that this will with a wireless network, but it can lead to lower frame rates due to data throughput. Essentially the main PC will send its entire OBS scene more or less uncompressed over the network, at a very high data rate, only to be properly compressed on the second PC that will do the actual streaming. However, we can still switch scenes on the main PC in OBS just as we always do.
OBS has a super neat feature that works great if you’re narrating over an existing audio track. It’s called Sidechain/Ducking, and it will automatically lower the audio of one source if an audio level is detected on another source. For example, when you’re playing a game, the audio would be lowered when you speak, and when you’re quiet the game audio could be played higher. It’s like MAGIC!
In this article I’ll show you how to set it up, and the values that I’m using for some of my streams.
Adding the Sidechain/Ducking Compression Filter
On the audio source in question, apply a filter. You can either right-click on the source in question, or use the little cog icon in the Audio Mixer for that. Add a Compressor filter and call it “Sidechain Compression”, or another identifiable name.
The default values work OK, but I’m using these as I find them more pleasing:
Output Gain: 0dB (default)
The important bit is set at the bottom, which which we can pick a Sidechain/Ducking Source. Set this to your microphone source from the drop-down menu. That way the Compressor knows which other source to listen to and apply the effect. When a level above a certain threshold is detected, the filter kicks in. Anything below that will not trigger the filter.
It’s worth doing some test recordings to see which exact values suit your needs. To figure out the threshold, take a look at the audio meter while you’re not speaking into your mic. You’ll see some low level noise on the left, know as the noise floor. Make sure to set the sidechain threshold to somewhere above that level so that it won’t trigger accidentally.
Most voice recording sounds better with a little bit of compression applied. It’ll make the quieter bits louder, and make the louder bits quieter. In addition, there’s usually a little bit of noise that is picked up even with the best of microphones. It’s just a fact of audio life.
Thankfully OBS has two great filters that can be used in combination to great effect, first compressing your voice, and then adding a bit of noise reduction afterwards. I’ll show you how to do it, and the values that work well for me in this article.
In principle, we use the latter to route a source into the VB-Cable (a virtual destination), then we pick up the VB-Cable output as a separate input in OBS. We can then adjust its levels independently from other sources or apply filters if necessary. This all sounds more complex than it really is, so let me illustrate this with an example.
VB-Cable installs like a regular app on Windows, and does not need to be started. It’s like a permanent audio device driver on your system. There are three versions in total: the free VB-Cable, as well as two donation ware items called VB-Cable A/B and C/D. We don’t need those, but if you ever require more than one routable audio destination, give them a try. Either one will get you two more destinations.
I took this screen grab so illustrate which download button to click for the regular VB-Cable:
A wonderful new feature in OBS 24 is the ability to pause you recordings. This can come in handy if you want to create a quick and rough recording, without taking multiple files into a video editor. It’ll speed up your workflow and increase quality for files you want to send away “as is”.
Question is: HOW do we pause recordings in OBS 24 and above?
If you’ve been looking for a pause button but can’t find it, let me give you some pointers on how to make it magically appear. First of all, OBS can’t pause live streams. Those have to be delivered continuously. By default, the encoder for recordings is the same that’s used for live streaming. It’s efficient and reduces processing overheads.
Under Settings – Output – Recording you’ll see an option that’s set to “Use Stream Encoder”. If you change that, it means OBS will open up different settings that can be configured independently of those used for streaming (for example, you could use a software encoder instead of a hardware encoder, or use a different bitrate).
As soon as we change this, and then press the big RECORD button in the main interface, we’ll see that it has a PAUSE option next to it.
Now we can either stop the recording as usual (closing the file), or pause the recording and then un-pause it so that OBS keeps recoding at the end of same file.
A while ago I made a video about how to use OBS Studio for Screen Recordings. If you’re new to OBS, I recommend watching it to see how this thing works. I’ve been meaning to make an update to this and explain how to switch from one scene to another, but since it’s a complex process I decided to write this article instead. It might be easier to follow in words and screenshots.
Scenes are collections of items that appear on your (captured) screen. They allow you to craft something you’d like to show to your viewers, for example your desktop and an inset of your webcam. From time to time you may want to show something else, such as a video, or your web cam in full screen, or a zoomed-in portion of your desktop. That’s where scenes can be helpful, because each scene can show something different. You can then seamlessly switch between them with ease.
Let’s take a look at how we can make such magic happen.