Cropping in OBS allows you to cut out areas from your webcam or source. The standard crop will cut out areas from the sides of the camera. Cropping your camera can help make it fit better in an overlay or scene. The crop feature is also used to remove any unwanted background clutter from view.
Quick Cropping with the Alt Key
The easiest way to crop your webcam in OBS is to hold the Alt key on your keyboard, left-click, and drag the sides. To crop the image with this method you will need to have the source selected and ensure that it is visible.
With the webcam source selected, the border of the source will be red. Once a side has been cropped the outline will turn green.
Holding the Alt key and dragging in a corner will allow you to crop two sides at once. This is helpful as it speeds up
Precise Cropping with Edit Transform
The edit transform menu can be used for a precise cropping. This allows you to choose the exact amount of pixels to be removed from each side. The transform window also allows you to choose the exact positioning and size of the webcam.
The transform menu can be opened by right-clicking on the webcam source, and going to transform, then edit transform. Alternatively, select the source and press Ctrl + E.
At the bottom, you will see the crop input boxes. Each input allows you to crop from one side. You can manually input the amount of pixels you wish to crop or use the arrows to adjust the values.
The webcam source will be positioned to hug the top left corner by default. This can be changed using the “Positional Alignment” drop menu.
With the edit transform menu open you can still use the Alt crop method. The crop values will manually adjust in the transform menu as you drag the sides in. Combining the two methods allow you to quickly and precisely adjust the crop on your camera.
Abstract Shape Webcam Crop Masks
Some streamers prefer to use abstract shapes for their camera. It allows the webcam to fit nicely in overlay designs. Unique camera shapes can be created using the image mask filter.
The filter uses a black and white image to define a mask for the webcam. The white areas on the image will be visible, with the black areas cropped out.
1. The filter menu can be opened by right-clicking on the webcam source and choosing the filter option. All the audio and effect filters for the layer will be shown on this page.
2. Press the plus icon under the Effect Filters panel, and choose to add the “Image Mask/Blend” filter.
3. Ensure the type is set to Alpha Mask (Color Channel), and the color is set to white. These should be set by default.
4. Click the “Browse” button to open the file explorer window.
5. Locate and open the mask image file. The moment the file is loaded, the webcam will be masked accordingly.
The easiest way to create a mask for your webcam is using a raster graphics editor like photoshop. It is recommended to match the size of the mask to your OBS canvas resolution. The resolution is typically set to 1920 pixels wide, by 1080 high.
Green Screen Alternative
Often the purpose of cropping a webcam is to remove enough of the background as possible. Too much cropping can cause the person to move out of frame during their stream or recording session.
A green screen can be used in an effort to hide the background while still capturing a wide view of the camera. The green screen needs to be placed behind you while you stream or record. The green area can be removed in OBS using the Chroma Key filter.
To achieve the cleanest mask possible on your webcam, good lighting is required. Correct lighting allows more information to be picked up from the camera. The added color and definition help the filter to distinguish between the background and foreground easier.
Removing a Crop in OBS
The quickest way to remove an existing crop is to select the source and press Ctrl + R on your keyboard. Alternatively, you can right click on a source, and go to “Transform”, then “Reset Transformation”. All crop changes will then be removed, restoring the source to its default state.
Resetting the transformation will also rescale your cropped media. Another plausible method is to hold the Alt key on your keyboard, then left-click and drag the side. Dragging out the sides or corners while holding the Alt key will fill out the crop, effectively removing your changes.
Resizing Your Webcam in OBS
Resizing your webcam works differently than cropping. Instead of cutting off a portion of the camera, you’re making the entire source smaller. Combining resizing and cropping may be required to position your camera neatly behind an overlay.
The camera can be scaled by clicking and dragging one of the sides or corners. Naturally, the source will retain its aspect ratio. If you want the ratio to be changed, then you will need to hold the shift key as you rescale the source.
Exact sizing changes can be made by using the edit transformation window. The fastest way to open the transform window is by pressing Ctrl + E on your keyboard.
Using a Crop in Multiple Scenes
Instead of adding your camera to each scene as a source, you can create a webcam scene. This is a scene that will only feature your webcam and overlay. This is often referred to as scene nesting.
Because the webcam is nested you can make crop and mask adjustments in full size. The scene can then be added as a source and scaled-down in other scenes without losing quality.
Using a webcam scene can help if you ever change the cropping of your camera. Rather than having to change every scene individually, all adjustments can be made in one scene.
Another option is to copy and paste the source transform settings into another scene. Both the copy and paste transform options can be found by right clicking on the layer and expanding the transform menu.
Final Thoughts
The crop feature is quick to learn, and helpful if you’re going to be streaming or recording content with OBS. While cropping can be used to make adjustments to a camera, you can also crop out any visual source. This allows for more customization and can be a helpful tool when setting up advanced scenes in OBS.
