Budget chroma key green screen with Android as webcam on OBS Studio

Technoloman on Chroma Key on OBS Studio.

Hello, here is Max Francisco from Technoloman.com and today I will be showing you how to build a cheap green screen for Chroma key. Then using your android phone as a web cam using DroidCam app, then put both of them together on OBS to add the chroma key filter, select the web cam source and add gameplay or a browser window as background to your video as you record or stream.

Starting with the chroma key, I used an old retractable banner stand . These are used at conferences or companies, or store openings, etc… it’s possible you can find one for free close to office parks and such. I got me one from my current company. They were throwing away a few old ones and I just got one to take home.

Cover it with green muslim fabric which is usually the “official” chroma key color for fabric as you will find online. Or you can just do like I did which was using a bright green single color wrapping paper. I taped two of them together to make them wider than the banner and still couldn’t make it wide enough for the web cam width, so I ended up just cropping the window size later on OBS. More on that later.

Using my Android phone as a webcam via USB


One can achieve that by using the DroidCam app. If you look up “android camera to USB pc” on google you are going to find a lot of old results that don’t work anymore. To save you time, look up “android phone as a web cam using DroidCam app” and you might as well find us.

  • Download the free DroidCam App on your Android, by Dev47apps
  • Download the Droid Cam client on your Windows PC Both can be found on the https://www.dev47apps.com/ website along with instructions
  • USB connections are possible via a program called “Android Debug Bridge”, or ADB. You can search on Google for info on ADB in Android
  • ADB works when manufacturer drivers are installed on the computer (ie. drivers from Samsung, or Sony, or HTC, etc.). But if they are not, here are some steps you need to take:
  • Install the drivers for your device on computer.
    Option 1: Universal Driver: https://adb.clockworkmod.com/
    Option 2: Device specific driver: http://developer.android.com/tools/extras/oem-usb.html#Drivers.
  • On your Android, go to Settings -> Developer Options, and enable “USB Debugging” on the device. Google starting from Android 4.2 and higher, hid the Developer options screen by default. To make it visible, go to Settings > About phone and tap “Build number” 7 times. Return to the previous screen to find “Developer options” at the bottom.
    See also: http://www.cnet.com/how-to/restore-the-developer-options-menu-in-android-4-2/
  • Plug the device back into computer over USB. If you get a dialog asking “Allow USB Debugging”, you need to tap OK. Sometime you need to open “USB Options” from the notification area on the device and pick “PTP” mode for that to show up.

Adding DroidCam as a source on OBS Studio.


Once you start the client by USB, you should see the window with your image.


Connecting the DroidCam to OBS studio


To be able to capture your image on OBS you need to enable the DroidCam on UBS. I achieved that by using the Window Capture option.

DroidCam as Source on OBS

  • On the bottom of the screen at OBS, at Sources, add a new one Clicking the Plus sign (+), then Window Capture and at Window, the first dropdown you should see the DroidCam option available if the DroidCam client is on on the PC.
  • You just added you Android phone as a video cam using the USB.


Put both together to achieve the chroma key effect


After the video source is setup on OBS, now it’s time to make your background disappear.

  • Sitting in front of the budget green paper background we built earlier, on OBS, right click the Window Capture source (with the DroidCam) we just added.
  • Click Filters all the way at the bottom. Then on the bottom left side, click the Plus sign, (+) and select the option Chroma Key.
  • Green usually will be the color of choice but you can actually change this to other colors. Some of the options here are to increase of decrease the Smoothness and the Key Color Spill Reduction, Opacity and other options. Play around with these to achieve the desired effect.

Adding Chroma Key filter on OBS.

I hope these tips were enough to help you set up with a home made chroma key background, using your droid as a webcam and streaming your gameplay or browser.

To achieve the latter, all you would need on OBS is another Source, using the Browser source option, or you can use the Display option to capture the content of the full display including task bar, clock, etc..

To capture Gameplay, the source would be Game, then pick the Window where the game is going on. Accessing this feature with the game already playing will show your game of choice making what to select very clear.

Max Francisco has been doing digital projects in Brazil and the US for the last 15 years.