How To Use Chroma Key Software For Live Streaming

How To Use Chroma Key Software For Live Streaming

The use of chroma keying has become quite popular in recent years, with many applications of this video effect used for live streaming. Chroma keying is used to remove the background of a video scene which is then composited over another scene or image. The most obvious use of this technique is for weather broadcasts, where the presenter is composited over the top of a weather radar image. In more recent times we’re seeing video game streamers chroma keying themselves into their live streams.

In the days before computers, creating this effect was an tedious process. If you want to learn how they did chroma keying in the past, then I’d recommend watching this great video by Tom Scott.

These days most live streaming software packages include chroma keying as a feature. In this guide we’ll show you how to achieve this great effect with OBS (Open Broadcaster Software).

Equipment needed:
Green Screen Setup

  • A solid green background
  • A webcam or video camera
  • Lighting
  • OBS

As with all things in video production, you can easily spend a fortune on equipment. For the purpose of this guide, we’ve tried to keep things reasonably cheap. For the green background we picked up some green fabric from a local arts and craft store. Alternatively, you can buy green screen paint if you’re looking for a more permanent setup.

We’re using a Logitech c930e webcam for the video source. If you want to use a better quality camera, such as a DSLR, then you will need a video capture card. We often recommend the Magewell HDMI to USB3 dongle for video capture.

Lighting is very important when it comes to green screens as you want the green to be as even as possible. In our set up we’ve used a single box light. We’ll go into more detail about lighting below.

Stage set-up:

Green Screen Lighting Guide

The first thing to do with any live stream is to plan your shoot. Will the camera remain stationary, or will you be moving it? Once you’ve determined the shot, you can calculate roughly how much green screen you need. It’s prudent to allow for a bit of extra green screen around the subject to avoid having them clipped outside of the chroma keyed area.

I won’t delve too deep into the best lighting setup, but for professional shoots it’s recommended to have three types of lighting. Back lights, key lights and fill lights. To the right is an image which gives you an idea of a typical lighting setup. If you want to learn more about green screen lighting, I recommend checking out this video.

Additionally, consider having a reasonable amount of distance between the subject and the green screen. The closer the subject is to the screen, the greater the shadow cast.

Green Screen Shadow

OBS set-up:

If you’ve correctly set-up the green screen and lighting, the chroma keying should be reasonably simple.

  1. Open up OBS and add your video source.
  2. Right click on the video source and select ‘Filter’.
  3. Click the ‘+’ under the ‘Effects Filters’ section, then select ‘Chroma Key’.
  4. Enter a name for the effect layer.
  5. When adding a chroma key OBS will automatically generate some baseline settings. In most cases you’ll need to fine tune these settings. I’d recommend experimenting with the sliders to see what they do.

Once you’re happy with the chroma key settings you should then do a quick run through of your shoot. If the subject is going to remain stationary, you’re likely good to go. If there’s going to be movement, you should double check every position the subject will be in to make sure the chroma key settings are correct for the whole shoot.

After you’ve confirmed the chroma key settings are correct, you can now add your background layer(s). You will need to make sure they’re below the chroma keyed camera layer in OBS.

Extra Tips:

  • The process for chroma keying is quite similar in Wirecast.
  • Live chroma keying can be quite CPU intensive, so make sure your computer is powerful enough.
  • Make sure the subject doesn’t have any green, or reflective material on them. Often blonde hair can cause issues with reflection.
  • In OBS you can chroma key images, and videos – not just camera feeds.
  • If you have many shades of green, you can chroma key a source multiple times, each time specifying a different shade of green.

23 Comments

  1. Michael Hoskins

    Hmmm, when I go to the Filters list in OBS, there is no “Chroma Key.” I had just downloaded from OBSProject.com, where did you get your version?

    1. Leo

      go to source list select camera and then click with right mouse button select filter and ….. now you see filter, select it and appear the chroma key effect.

  2. Michael Hoskins

    Oh, it would have helped if I was looking in Video Filters, instead of Audio FIlters. 😉

    1. Cameron

      Hi Michael,

      Yep, it’s under the ‘Effects Filters’ section 🙂

      Cheers,

      Cameron

  3. Dylan Owen

    I see a lot of production methods using a green screen wall and a floor, how about ceilings? if you wanted to give the impression of a confined space?

    1. Cameron

      Hi Dylan,

      You can certainly use a green screen/chroma key paint on the ceiling, just make sure it’s lit correctly.

      Cheers,

      Cameron

    2. Joee Here

      Is your setup gonna be against the wall? lol

  4. Melissa Ruth

    Is there a page that helps us to know how to add the background image?

    1. Cameron

      Hi Melissa,

      You can add a background image by adding a new ‘source’ (click the + below sources), then selecting ‘image’. Make sure the that the image layer is below the chroma keyed layer.

      Cheers,

      Cameron

  5. Rohan Sethi

    Hey thanks for these mega helpful guides.

    Do you know if it is possible to capture both the chroma keyed video, and headset view simultaneously?

    (As two separate video files of the two views) many thanks.

    1. Cameron

      Hi Rohan,

      So you want to record two different views? You can achieve this by having two instances of OBS open and recording each quadrant separately.

      To do this you will need to create a shortcut to the OBS EXE and add -multi to the end of the target. e.g OBS\OBS.exe” -multi

      Screenshot: http://i.imgur.com/IMlfRct.png

      Cheers,

      Cameron

  6. eitan

    i tryed to put high resolution picture in the back and it is very pixelise what can be wrong?

  7. hello i just bought a green screen and so far i am really happy with it but i’ve noticed that the area where i use a green screen is a couple shades lighter than the actual video. I feel it makes it look less professional. Do you have any idea on how I can fix it. i will attach the link to a video of mine so you can see what i am saying if you would like. https://youtu.be/nXqo6VOH0J0

    1. Cameron

      Hi Tyler,

      The best way to solve this issue is to have better lighting on the green screen. You want the lighting on the green screen to be as even as possible.

      Once you’ve got even lighting on the screen you can play around with the settings to make sure its removed everything. Make sure to not overdo the ‘color key spill reduction’ setting, as if it’s too high it will turn everything grey.

      Cheers,

      Cam

  8. Amanda McIntyre

    I’m brand new to all of this. I’m wanting to use these effects for Facebook Live streaming. Will this software work for it? Also is this platform only available on my computer and not my phone?

    If anyone has any tips for me that would be great! I bought a green screen kit online with 10 lighting options and 3 different backgrounds (green, white, ad black).

    1. Neenan

      OBS Studio (The current latest/supported version of OBS) is currently desktop/laptop computer only and will not be compatible with your phone. On the other hand, OBS can stream to Facebook, though you would need to look through your settings to find your Stream Key. A quick google search will tell you where to find this and how to put it in OBS.

      Hope I helped.

  9. Nathan Kaye

    Like Amanda, I also want to use my green screen for Facebook Live streaming. Is this doable with OBS?
    Thanks so much for your help solving this riddle…
    Cheers,
    Nathan
    🙂

    1. Cameron

      Hi Nathan & Amanda,

      Yep the same chroma key method can be used with OBS and Facebook Live.

      There might be a smart phone app which let you do this, however I haven’t seen one. Chroma keying can be quite CPU intensive, so it might not be possible on a smart phone.

      Cheers,

      Cam

  10. Mark Freeman

    Will this allow me to have a green screen effect while streaming over BlueJeans?

    1. Cameron

      Hi Mark,

      This method will work with any platform that accepts RTMP input.

      Cheers,

      Cam

  11. I am trying to get our morning announcements broadcast going at our school using OBS. I want to be able to do simple backgrounds like a flag, Cafeteria, maybe some graphs when we are doing grade level competitions for money collects. Is chroma key what I need to use my green screen?

  12. Madison

    So I’m using a Mac and there is no “right click”. Where do I find the “add filter” option on the OBS?

    1. Cameron

      Hi Madison,

      If you’re using the touchpad then you can two finger click on the layer to see the right click menu. Alternatively you can control + left click to see this menu.

      Cheers,

      Cam

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