How To Broadcast Live With A Green Screen

August 14, 2013

By James Bruce

I’ve already showed you the basics of green screen videography with pre-recorded footage in iMovie or Premiere, so you could superimpose yourself onto any video or background. Wouldn’t it be cool if we could use this green screen effect for a live broadcast – like on Google Hangouts, or Skype?

“Yes indeed it would be, James” – is the answer you’re looking for there, and you’re in luck because I’ve been having a go at doing that very same thing. Read on to join the cool kids club as we play with live green screen broadcasting on Mac or Windows.

No idea what Google HangOuts is? Tina fills you in on how to use HangOuts to chat with friends, and 5 reasons HangOuts are cooler than Skype; read those, then come back and wow them all with your green screen skills.

Mac OS X: CamTwist (Free)

CamTwist is remarkably useful considering it’s completely free. Unfortunately, it’s also about non-user-friendly as they come. Upon first launching the app, you’ll be greeted with this interface, which is only slightly less intimidating than a spreadsheet from the 80s.

First, hit CMD-P to open up the preview window.

The premise of CamTwist is that you add input sources, and effects, and end up with a composite video you can then feed into other applications – a DIY webcam, if you like.

Double-click on a video source – your webcam would be an easy place to start at – then double-click some effects to add them. Effects stack, though your results will vary of course depending on what you choose. I quite like this “dot screen” and “earthquake” effect.

Now, onto our green screen. For this we’ll need a background source – your desktop is probably the easiest for testing, but you could also use a pre-recorded video source (I could only get .MOV formats to work), another webcam, or just a slideshow of images. Double click to add your chosen source to the scene.

Next, highlight Webcam and select the PIP (picture in picture) button from the bottom of the list. This will overlay your webcam onto the scene. To setup the Chroma-key, select the PIP Webcam from the Step 3 column to open the settings screen.

Check the box next to Chroma key, and choose the colour. The easiest way to find the colour is using the magnifying glass in the top left of the colour popup. Adjust the threshold to tweak results – as you can see above, mine turned out pretty badly thanks to poor (uneven) lighting.

One caveat here: CamTwist won’t work with 64-bit applications, which the latest Flash player and most web browsers are – so if you’re unable to find the virtual CamTwist video source in Hangouts or otherwise, you’ll be stumbling up against this issue. To get around this, you should try running the app in 32-bit mode by right clicking on the application and checking the relevant box. If that doesn’t work, the CamTwist developers suggest installing an older version of Flash also – 10.3 should be fine – which also still runs in 32-bit.

Hopefully someone will deal with this 64-bit incompatibility at some point.

Windows: SparkoCam ($20)

I can’t find a free solution do to this on Windows, but SparkoCam is the cheapest and also lets you use a DSLR camera as a live video input source, which is fantastic and will give you far better quality than a webcam – this alone makes it worth the price, I think.

Start by selecting your video source on the initial screen. To use a DSLR, plug in the supplied USB cable and switch the camera to video mode. You might want to disable auto-focus, or you’ll end up with annoying scratching sounds as its tries to focus every 3 seconds.

To add the green screen, move over to the Effects tab (next one along). Select a background first or you won’t know when it’s working. By clicking on Detect the app was able to automatically add the right colour, and the quality of the screening was actually real good – no tweaking necessary this time. Unfortunately, it’s slightly limited in that you can only use a static background image – you can’t broadcast your desktop, or overlay on top of another video.

The Bottom Line

Green screen video is just great fun, live or pre-recorded. It can be a bit fiddly getting drivers to work correctly for CamTwist, especially considering that running an older version of Flash can be a serious security risk, but with enough tweaking you should get there in the end and the forums are full of users ready to help.

So… any ideas on how you’ll use green screen? Share your thoughts in the comments, below.

For more tips and advice on using Google Hangouts, Bakari gave some advice about using it for online meetings, and here are some creative ideas to get more out of HangOuts.

Image credit: Lego Figure Chroma Key IMG_2494 (Lær IT)

via How To Broadcast Live With A Green Screen.