Create Side-by-Side Vertical Split Videos in OBS

This guide provides a straightforward walkthrough on how to set up a side-by-side vertical split-screen reaction layout in OBS Studio. You will learn how to import your sources, crop them into vertical aspect ratios, and align them perfectly side-by-side for a professional-looking reaction video.

Step 1: Add Your Video Sources

First, you need to bring both video inputs into your active OBS scene.

  1. Go to the Sources dock at the bottom of the screen.
  2. Click the + (plus) icon.
  3. Select Video Capture Device to add your webcam or camera.
  4. Click the + icon again and select Media Source (for pre-recorded video files) or Window Capture/Display Capture (to record a YouTube video or game playing on your screen).

Step 2: Crop the Sources Vertically

To create a vertical split, you must crop both horizontal sources so they can sit side-by-side without overlapping.

  1. Click on your camera source in the preview window to select it.
  2. Hold down the Alt key (Windows/Linux) or the Option key (Mac).
  3. Click and drag the left and right bounding box handles inward. This crops the source instead of resizing it. Crop it until it looks like a narrow vertical rectangle.
  4. Release the Alt/Option key.
  5. Select your reaction content source and repeat the process, cropping the left and right sides to create a matching vertical rectangle.

Step 3: Align and Resize the Layout

Now you must position the cropped videos side-by-side to fill the screen.

  1. Click and drag your cropped camera source to the left half of the canvas.
  2. Click and drag the reaction content source to the right half of the canvas.
  3. To resize them, click and drag the corner handles of the bounding boxes (do not hold Alt/Option this time). Expand them so they match in height and fill the screen from top to bottom.

To ensure both sides are perfectly symmetrical and split exactly down the middle:

  1. Right-click your left-side source and select Transform > Edit Transform.
  2. Assuming you are using a standard 1920x1080 canvas, set the Size width to 960 and height to 1080.
  3. Set the Position X to 0 and Y to 0.
  4. Right-click the right-side source, select Transform > Edit Transform, and set its Size to 960 and 1080.
  5. Set its Position X to 960 and Y to 0.

This mathematical alignment ensures a perfect 50/50 vertical split down the exact center of your screen.