How to Crop a Webcam into Shapes in OBS

OBS Studio has no shape picker for webcams. To get a circle, rounded square or any other shape, you combine two built-in tools: a Crop/Pad filter that trims the camera to the right proportions, and an Image Mask/Blend filter that uses a picture of your shape as a stencil. The webcam shows through the shape and the rest becomes transparent. If you also need a portrait (vertical) layout, rotation is a separate step, and the order of these steps changes the result.

The short answer

• 1. Add your webcam as a Video Capture Device source.
• 2. Add a Crop/Pad filter to trim it to the proportions your shape needs, such as a square for a circle.
• 3. Add an Image Mask/Blend filter below the crop and point it at an image of your shape.
• 4. Resize and position the shaped webcam in your scene, and rotate it with Transform if you need portrait orientation.

"Crop" can mean two different things here. Cropping only cuts straight lines off the edges, so it always leaves a rectangle. A curved or angled shape needs a mask. Most shaped-webcam setups use both.

Before you start

• OBS Studio is installed and your webcam is connected.
• Your operating system allows OBS to use the camera. On macOS, check the Camera list under Privacy & Security. On Windows, check the camera privacy settings.
• No other app, such as a video-call program, is holding the camera. Many webcams work in only one app at a time.
• You have a mask image for your shape. This is usually a PNG. The next section explains how to make one.

Exact menu names and filter labels can vary between OBS versions and operating systems. The steps below use the common labels. If one doesn't match, look for the nearest equivalent in your version.

Make a mask image

A mask is a plain image that tells OBS which parts of the webcam to keep. You can make one in any image editor that exports PNG. Make the canvas match the proportions your webcam will have after cropping. For a circle, that means a square canvas. The Image Mask/Blend filter stretches the mask to fit the source, so a square circle mask applied to an uncropped widescreen camera becomes an oval.

Mask type in OBS | How the image should look | What OBS keeps

Alpha Mask (Alpha Channel) | Your shape drawn on a transparent background | Areas that are opaque in the image

Alpha Mask (Color Channel) | A white shape on a black background, no transparency needed | White areas stay, black areas disappear, grey becomes partly see-through

Both types work. The color-channel version is often easier to make in a basic editor. For a soft edge instead of a hard cut-out, feather or blur the edge of the shape in your image editor. The gradient becomes a gradual fade in OBS.

Step by step in OBS

• 1. In the Sources panel, click + and choose Video Capture Device. Select your webcam and confirm. Check: your live camera image appears in the preview.
• 2. Right-click the webcam source and choose Filters. In the Effect Filters section, click + and add Crop/Pad.
• 3. Enter crop values for the left, right, top and bottom edges until the remaining area matches your mask's proportions. For a circle, crop the sides until the image is square. Check: the source outline in the preview shows the proportions you want, such as a square.
• 4. In the same Effect Filters list, click + again and add Image Mask/Blend.
• 5. Set Type to the alpha-channel or color-channel option that matches your image, then browse to your mask file. Check: the webcam now appears in your shape, with empty or transparent space around it.
• 6. Make sure Crop/Pad sits above Image Mask/Blend in the filter list. OBS applies filters from top to bottom, so the crop must happen before the mask. If you can drag filters in your version, drag them into this order. If not, use the up and down arrows.
• 7. Close the Filters window. Drag the source's corner handles in the preview to resize it, then move it where you want it in the scene.

OBS also lets you crop by holding Alt (Option on macOS) while dragging a source's edge in the preview. This is quick for one-off framing. The Crop/Pad filter is more precise, and it keeps the crop in the filter chain where it lines up with the mask.

Rotating for a portrait layout

Rotating the webcam and changing the shape of the whole output are two separate jobs. Do whichever applies to you.

• Rotate the webcam source: right-click it and choose Transform, then pick a 90-degree rotation. Use this when your camera is mounted sideways, or when you want a tall camera window inside a normal widescreen scene.
• Make the whole output vertical: in Settings, go to Video and set the base (canvas) resolution and the output resolution to a tall size, such as 1080x1920. Use this when the final video itself must be portrait, for example for short vertical clips. Changing the canvas does not rotate the camera.

Order matters for masks. Filters, including crop and mask, are applied to the camera image in its original orientation. The Transform rotation is applied afterward, to the finished shaped result. A circle looks the same either way. A shape with a distinct top, such as a heart, a tall rounded rectangle or a badge, will turn with the rotation. Draw that kind of mask in the camera's original orientation, or rotate the mask image before loading it, so the shape ends up the right way up after the transform.

Adding a border (optional)

The mask itself doesn't draw an outline. To add one, create a PNG of just the outline, such as a ring for a circle, with a transparent centre. Add it as an Image source, place it above the webcam in the Sources list, and line it up over the shaped camera. Group the two sources if you want them to move and resize together.

How to know it worked and what that doesn't prove

Seeing the correct shape in the OBS preview confirms three things: OBS can access the camera, the crop and mask apply in the right order, and the shape has the right proportions. To check the final result, make a short test recording. Play it back and confirm that the shape, its position and any rotation look the same as in the preview.

Neither check tells you how the shaped camera will look in a live call or stream. If you send OBS into a call app with the Virtual Camera, the app receives the whole rectangular canvas. It doesn't receive a cut-out shape. The transparent areas around your shape show whatever sits behind the webcam in your scene, or black if nothing does. To control that, place a background image or colour source below the webcam in your scene. Call quality, including resolution, frame rate, lighting and how the other side's app scales or mirrors your video, depends on the call service and your connection. A quick test call with someone else, or the app's own camera preview, is the only way to check those.

Common problems

• The circle looks like an oval: the source isn't square when the mask is applied. Adjust the Crop/Pad values, and check that the crop filter is above the mask.
• The shape shows the wrong part of your face: change which edges you crop. For example, take more off the bottom and less off the top to move the window up.
• Nothing is cut out, or the whole camera disappears: the mask type doesn't match the image. Switch between the alpha-channel and color-channel options.
• The webcam source is black: this is a camera-access problem, not a mask problem. Disable the filters to confirm. Then check your OS camera permission and close other apps that may be using the camera.
• The shape is upside down or sideways after rotating: rotate the mask image itself, as described in the portrait section.
• The edges look jagged: use a larger mask image, or add a slight feather to the shape's edge in your image editor.

Some third-party OBS plugins add ready-made shape masks or rounded-corner options. Their features, compatibility with your OBS version and upkeep vary, so check each plugin's own documentation. The built-in crop-and-mask method above needs no add-ons.