How to Round Corners in DaVinci Resolve

To round a video in DaVinci Resolve, open the clip in Fusion, select MediaIn1 and add a Rectangle mask from the toolbar. Confirm that Rectangle1 feeds MediaIn1’s blue mask input, then select Rectangle1 and increase Corner Radius. Keep Soft Edge near zero for a clean card, and put a background on the track below so the transparent area outside the shape doesn't turn up as black.

The clicks themselves are quick. What catches editors is everything around them: the mask lands on the wrong node, non-uniform scaling stretches the curves, or a perfectly good transparent result looks black because nothing sits underneath it. The rest of the guide covers the dependable Fusion setup first, then the faster alternatives for graphics and multi-clip sequences.

Choose the Method That Matches the Job

The native Fusion Rectangle workflow is available in both Resolve Free and Studio. Resolve 21.1 was released on September 8, 2026, and every control named below matches the 21.1 edition of the Resolve 21 Reference Manual.

Round a Video with a Fusion Rectangle Mask

1. On the Edit page, put the clip you want to round on V2 and the background video, color or graphic on V1.
2. Select the V2 clip and open the Fusion page.
3. Check that MediaIn1 is connected to MediaOut1.
4. Select MediaIn1, then click the Rectangle mask button in the Fusion toolbar. Resolve should create Rectangle1 and wire it to the blue mask input on MediaIn1.
5. Select Rectangle1 and set Width and Height so the mask sits just inside the frame.
6. Increase Corner Radius until the curve suits the card.
7. Leave Soft Edge at zero or very low for crisp, UI-style corners. Only add feather when the composite really needs a softer edge.
8. Go back to the Edit page and play the whole clip over its final background.

The checkerboard in the Fusion Viewer is transparency, not a fault. On the Edit page, that area shows whatever sits on the lower track. With no lower track, the timeline background is normally black, so the finished frame looks as if the mask added a black border.

If the Rectangle Does Nothing, Check the Connection

A blue input takes an effect mask, but what the mask does depends on the tool receiving it. Masking MediaIn cuts the source image. Masking a Transform normally limits where the transformation applies; it won't make everything outside the shape transparent on its own. On a Merge, the mask controls where the foreground shows over the background.

Drop a Rectangle into empty space and Resolve creates the tool without necessarily connecting it where you meant. Drag Rectangle1’s output square onto MediaIn1’s blue triangle, or delete the loose node, select MediaIn1 and add Rectangle again. I'd take the second route: it's usually faster, and it won't hook the mask to MediaOut or some unrelated effect.

If the node graph still feels opaque, the site’s Fusion tutorial for beginners explains viewers, image connections, masks and Merge nodes before you build a bigger composite. The Fusion learning hub helps you choose the next workflow by task, and Blackmagic offers current Resolve training books and lesson files with downloadable practice projects.

Resize the Card Without Stretching Its Corners

Rectangle1 defines the visible shape. A Transform node moves and scales the image. Those two jobs look interchangeable right up until X and Y get scaled by different amounts.

Stretch the already-masked image horizontally or vertically and its corners stretch with it. To move or resize the picture inside a fixed rounded window, transform the source first, then mask a Merge over a transparent Background. Don't just move Rectangle1 onto a Transform and expect it to cut the output alpha.

Use this routing: MediaIn1 into Transform1, then Transform1 into Merge1’s green foreground input. Connect Background1 to Merge1’s yellow/orange background input and set Background1’s Alpha to 0. Connect Rectangle1 to Merge1’s blue effect-mask input, then Merge1 to MediaOut1. Leave Merge at Normal/Over. The mask reveals the transformed foreground inside the rectangle and the transparent background everywhere else.

The Background sets the Merge output resolution, so give it the dimensions of the intended composition before you adjust the mask. The manual’s Merge and Transform chapters distinguish this canvas from Transform sizing: whatever feeds the background input decides the output resolution, while a Transform changes the image’s placement and proportions without touching its pixel resolution. A mask doesn't change the real dimensions either. It only changes the area you see, which is why the manual reaches for a Crop node when a graphic genuinely needs a smaller canvas.

When the whole timeline needs a new shape, and not just one picture-in-picture card, use the separate aspect-ratio workflow for Resolve before you build the mask.

The Rectangle chapter describes Corner Radius as 0.0 for sharp corners and 1.0 for the maximum rounding. It isn't a pixel-radius field. Equal Width and Height values don't guarantee a square on a non-square canvas either, because Rectangle starts in the composition’s aspect ratio.

A 2025 discussion about Rectangle radius during resizing shows the practical problem well, though it isn't an official formula. Set the card’s final proportions and judge the radius at delivery resolution. If a mask fits one still image but not another, compare its Image-tab output dimensions and pixel aspect with the composition. Don't copy a fixed-pixel expression without accounting for those dimensions.

Use One Rounded Frame Across Multiple Clips

Copying the same Fusion composition to ten edits works until one clip gets trimmed, reframed or replaced. If the whole sequence should play inside one rounded window, select the clips on the Edit page, right-click and choose New Compound Clip. Open that Compound Clip in Fusion and apply the Rectangle mask once.

That's the clean way to handle a demo reel, an app walkthrough or a montage inside a persistent device-style frame. Keep the clips separate when their positions or radii have to change independently. A Compound Clip adds another level of timing, so give it a clear name and open it whenever you need to adjust the cuts inside. For a split-screen grid, the Resolve FX Video Collage effect has its own controls for tile spacing and rounded tile corners on the Cut and Edit pages.

An Adjustment Clip isn't my first choice for this job. It processes everything beneath it for its time range, which can pull in titles, backgrounds or overlays you never meant to touch. The dedicated Adjustment Clips guide explains that top-down scope and when a shared timeline effect is the better tool.

Save the rounded mask as a drag-on effect

A Compound Clip gives everything inside it one shared radius. When each clip needs its own corners, I'd turn the mask into an Edit page effect, because every clip then keeps its own Inspector values and nobody has to reopen Fusion. The manual's Fusion effect template steps start from any clip, and that clip isn't saved with the effect.

Build the comp with the Merge routing from the resize section above, so Rectangle1 sits on a node between MediaIn1 and MediaOut1. That's where those template steps place the effect nodes. Select all the nodes, right-click one and choose Macro > Create Macro. In the Macro Editor, tick Width, Height, Corner Radius and Soft Edge under Rectangle1, then name the effect. The Fusion macros and templates guide shows the Save to menu and the Effects template folder. Quit and reopen Resolve if the effect doesn't show up, then drag it from the Edit page Effects Library onto each clip and set its radius in the Inspector.

Build a Rounded Color Card for Text

For a label or lower-third panel, I'd start with a Fusion Background node over a Solid Color generator brought in from the Edit page:

1. Add a Background node and choose the card color and alpha.
2. Select the Background node and add Rectangle1 to its blue mask input.
3. Set Width, Height and Corner Radius on Rectangle1.
4. Add Text+ and Merge the text over the rounded Background.
5. Connect the Merge output to MediaOut.

Connect the rounded Background to Merge’s yellow/orange background input and Text+ to its green foreground input, so the text sits on top of the fill and doesn't mask the letters. For a plain Text title, you can skip the node setup entirely: the title's Inspector has its own Background group with a Corner Radius slider, and that's enough for a rounded box behind one line. The DaVinci Resolve text guide covers typography and title animation.

Let Text+ draw a box that fits the words

The Fusion card keeps its size, so a longer name means resizing the mask. Text+ can draw the box itself. Edit Text+ from the Titles category onto a track, select it and open Shading in the Inspector. Element 1 is the letter fill and sits on top, so pick a higher number such as 2 for the box. Tick Enabled and set Appearance to Border Fill. The Level menu decides what the box wraps: the whole text, each line, each word or each character.

The Round slider curves the box corners, and Extend Horizontal and Extend Vertical set the padding. I'd pick this over the node card whenever the wording will change, because the box is drawn around the text and grows with it. The Fusion card still wins for a panel with a fixed size or its own shadow branch.

Add a Border and Shadow That Follow the Radius

For a simple outline, duplicate the Rectangle onto a separate colored Background branch, turn off Solid on that copy and adjust Border Width. Then merge the outline over the rounded video. The Rectangle mask controls separate a filled shape from an outline. Check the stroke at final output size; don't assume Border Width is measured in pixels.

To make the outline draw itself around the card, I'd switch to the shape nodes, because sRectangle has a Length control made for write-on animation. Turn off Solid, set Border Width and choose Round for Border Style. Match Width, Height and Corner Radius to the card by eye in the Viewer. In the sRectangle controls, Length 1.0 closes the shape, so keyframe it from 0 to 1, and Position sets where the line starts. sRectangle only shows through an sRender node, so merge the sRender output over the card. The shape animation guide covers the keyframes. A static border stays simpler with the Rectangle outline above.

For a shadow, use another Background set to black with reduced Alpha, masked by a filled copy of the rounded Rectangle. Offset that mask’s Center, add Soft Edge and merge this branch behind the card. Leave enough canvas around it so the feather doesn't get clipped. Don't blur the finished video branch, because that softens the picture too. These are combinations of Background, Rectangle and Merge controls, not a named one-click shadow preset.

When the Edit-Page Method Is Enough

For a one-off video or still-image overlay, apply the Transform effect from the Resolve FX Transform category of the Effects Library and open its controls in the Inspector. Under Image Adjustment, Edge Rounding rounds the corners of the clip’s alpha, Edge Softness feathers that edge, and the Crop checkbox exposes crop controls for each side when you also need to trim the frame. Set Advanced Options, Edge Behavior to Transparent when the area outside the image should reveal a lower track. All of these controls are documented in the Resolve FX Transform chapter. It's a separate effect, not the built-in clip Transform controls.

Don't mix that effect up with the normal Inspector controls named Crop Left, Crop Right, Crop Top and Crop Bottom. Those remove straight strips and won't create curved corners on their own. The Resolve Inspector control guide maps those clip-level transform and crop groups.

Move back to Fusion when the rounding has to work alongside stabilization, several transforms, animation or a reusable border. The node graph shows the processing order, so you aren't left guessing which crop happened first.

On the Color page, a Power Window normally limits a grade. It won't make the rest of the clip transparent by itself. To use a window as an alpha matte, right-click empty space in the node graph, choose Add Alpha Output, and connect the window node’s blue key output to that blue output. A rectangular window’s Softness feathers its edge; it isn't Fusion’s Corner Radius. For a custom contour, use a Curve window or the Window palette’s Convert to Bezier option. For a regular rounded card, Rectangle in Fusion or FX Transform is simpler. The manual explains Color-page alpha output as a way to composite against clips on lower video tracks.

Round Only the Top or Bottom Corners

The standard Rectangle mask applies the same radius to all four corners. To round only the top corners of a panel, make the mask taller than the frame and move it down until the bottom curves sit outside the visible area. Reverse that placement when you only want the bottom corners rounded.

For four independently controlled corners, build a custom Polygon or B-Spline contour, or combine masks. The standard Rectangle doesn't expose four separate radius controls. This is shape construction, not subject isolation; when the main job is arranging several clips and not shaping their edges, use the site’s picture-in-picture workflow.

Animate the Card Without Making the Edge Wobble

Width, Height, Center and Corner Radius can all be animated. For a simple entrance, move or uniformly scale the finished card; don't change Width and Height separately. That keeps the proportions intact, although the radius still grows in pixels as the whole card grows. If the design needs a constant pixel radius while the card changes size, use a dimension-aware expression or a custom shape and inspect the result, because a fixed Corner Radius value on its own doesn't lock pixels.

Set the final radius at the final card size, then preview the whole animation at normal speed. Use the Spline editor to ease position or scale, and skip extra Corner Radius keyframes unless the design is meant to go from square to rounded.

Export Rounded Corners with or Without Transparency

If the rounded video is already composited over its final background, export it normally. The lower track has already filled the transparency outside the mask.

If another editor needs real transparency, remove any opaque background from the output and use Deliver’s Single Clip mode for the finished composition. Choose an alpha-capable format, codec and type that your installation offers, then turn on Export Alpha, which only appears under the frame rate setting when the codec supports alpha. The manual’s alpha export section gives ProRes 4444 and DNxHR 444 as Single Clip examples, and its RGBA list for individual clips adds ProRes 4444 XQ, TIFF and OpenEXR. Encoder availability still depends on the operating system, edition and installed build, so a codec on that list isn't a promise that every machine can encode it.

Ordinary H.264 MP4 delivery doesn't keep this alpha, and a .mov extension alone doesn't prove transparency either. Where the codec offers an Alpha Mode, Premultiplied is the default, so match straight or premultiplied alpha to the receiving application, then reimport a short render over a bright color. The transparent-video export guide covers format selection and edge interpretation in more depth.

For ordinary YouTube or social delivery, composite over the intended background first and use the settings in the Resolve export settings hub.

Fix the Five Problems That Waste the Most Time

The corners are black

The outside of the mask is transparent, but nothing sits underneath it. Put the rounded clip on V2 and a background on V1, or render to an alpha-capable format when the next application needs the transparency.

The entire clip disappears

Select Rectangle1 and reset Width, Height and Center. Check that Invert is off and that the mask feeds MediaIn1’s blue input. A tiny, inverted or off-screen Rectangle can hide the whole frame.

The curves turn into ovals

Look for a non-uniform transform after the mask, including Edit-page sizing. Reframe the source before the masked Merge described above, and check the mask canvas and pixel aspect. A mismatch in image dimensions can also make copied settings look different from clip to clip.

The edge looks soft

Lower Soft Edge and check the composition at delivery resolution. A small feather can hide aliasing; a big one makes a UI card look out of focus.

The mask works in Fusion but not in the timeline

Make sure you opened the same timeline clip whose Fusion composition you edited. Check that MediaIn1 still reaches MediaOut1 and that no later Edit-page crop or transform hides the rounded edge.

If this is the first effect you've built from clip geometry, the DaVinci Resolve tutorial roadmap places it after Inspector basics and before heavier Fusion work.

Rounded Corners in DaVinci Resolve: FAQ

Can I round corners in DaVinci Resolve Free?

Yes. The native Fusion Rectangle mask, Background, Merge, Transform and basic keyframe controls used here are all available in the free edition.

Why does Corner Radius change when I resize the Rectangle?

Corner Radius is a 0.0–1.0 shape control, not a fixed pixel value, so how it looks depends on the rectangle’s dimensions and the image geometry. Set the final proportions first, and check mask resolution and pixel aspect before you reach for a dimension-aware expression.

Can I apply rounded corners to several clips at once?

Yes. Put the shots in a Compound Clip and apply one Fusion Rectangle mask to the compound. Keep them separate if each clip needs its own framing or animation.

Can I round only two corners?

Yes. Extend the Rectangle past the frame so the curved corners you don't want sit outside the visible area. Use several masks or Shape tools when every corner needs independent control.

Why are my rounded corners uneven?

Look for non-uniform scaling after the rounded shape, and for mismatched mask dimensions or pixel aspect. Reframe the source before a masked Merge over a transparent Background, then judge the corners at final output size.

How do I export rounded video with transparency?

Render with a format and codec that offer alpha-channel output in Resolve, turn on Export Alpha, and check the file over another color. When the delivery platform doesn't accept alpha, composite over the final background first.

Jason Miller I run DaVinci Resolve Club, an independent publication. My guides explain editing, color, Fairlight, Fusion and delivery, with clear Free vs Studio limits.