Having Issues Streaming Retro Games With a 4:3 Aspect Ratio on Twitch? Try This Overlay Design Trick in OBS!


In a world where 16:9 is the norm, retro games created with the old 4:3 aspect ratio can be a pain to stream. Having to fit a square gameplay feed into a rectangle overlay leads to a lot of empty space, forcing streamers to create overlays specific to retro gaming.

One potential way to fill the extra space is to mirror the gameplay and blur the background. This effect is most commonly used when displaying vertically-shot videos on a widescreen display. Here’s how to implement this look on your stream!

What You’ll Need

  • OBS. This solution does not work in Streamlabs OBS
  • StreamFX Plugin

1. Install StreamFX. This plugin adds a myriad of new effects. You’re going to need the Source Mirror and Blur features of this package.

2. In your gameplay scene, add a new source. A new option should appear in your list called “Source Mirror”. Select that. From there, choose your gameplay source as the source to be mirrored. Mirroring the source allows you to edit a source without impacting the original.

3. Right click on your mirrored gameplay source. Select “Filters”. Under “Filters”, add “Blur”, which is now under the “Effects Filters” heading. I like to use Dual Filtering at size 5.00, but go with whatever look you like. Just note that the more dramatic of a blur that you use, the more strain you put on your computer.

4. Make two versions of that blurred mirror source. Align one of the sources so that the leftmost portion of the video is right against the left edge. Do the same for the other source on the right. If you want, crop both to be just the size you need.

5. Put your gameplay overtop. Crop the gameplay feed to cut out any blank space. Now you have a blurred background that moves with your game!


Again, there are tons of ways to address this challenge. This is just one approach. If this is a look you’d like to implement on your stream, I hope this guide helps you get there!


3 thoughts on “Having Issues Streaming Retro Games With a 4:3 Aspect Ratio on Twitch? Try This Overlay Design Trick in OBS!

  1. JG May 27, 2021 / 2:18 AM

    Norton says it’s a virus and blocks it from installing on Windows. Disabling the anti-virus and adding an exception does nothing. There seems to be little to no documentation anywhere about this (other than “I don’t use Norton” or “do you just install everything you find”).

    • Jett May 27, 2021 / 8:53 AM

      Can’t speak for Norton specifically, but some OBS plugins do trigger anti-virus, even though it isn’t (assuming you grabbed it from the right source).

      This video shows the same prompt I got from Windows. I had to tell it that I was okay with installing the file. Hope this helps!

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