To edit ultrawide footage without forcing it into 16:9, give your DaVinci Resolve timeline custom pixel dimensions, preserve the source proportions with Fit scaling, and export at the same dimensions. Here’s a practical 3440 × 1440 Mac workflow.

This guide is for a Mac user assembling ultrawide screen recordings, ordinary video clips and simple titles into one ultrawide movie. The instructions follow Blackmagic Design’s September 2026 DaVinci Resolve 21.1 Reference Manual, including its Edit, Fusion and Deliver sections. DaVinci Resolve 21.1 Reference Manual

Choose the actual output dimensions first

Start with the dimensions you want the finished file to have. For example, a 3440 × 1440 recording can use a 3440 × 1440 timeline and export. Resolve accepts custom frame sizes through the width and height fields beneath its timeline resolution selector; you do not have to choose a 16:9 preset. The manual describes these fields as the frame size used “For X × Y processing.” Reference Manual, Chapter 6: Project Settings

Use the actual pixel dimensions rather than relying on an “ultrawide” or “21:9” label. Dividing 3440 by 1440 gives approximately 2.389:1. That calculation describes this particular frame precisely and avoids choosing a slightly different shape by accident.

Check your Resolve edition before committing to a larger delivery size. Blackmagic documents the free edition as supporting finishing up to 3840 × 2160 at 60 fps. The 3440 × 1440 example stays within those dimensions. For a 5120-pixel-wide deliverable, use Studio rather than assuming that a short frame height bypasses the free edition’s UHD boundary. DaVinci Resolve Studio: edition capabilities

If you need a smaller version of a 5120 × 1440 composition, an illustrative proportional reduction is 3840 × 1080: multiply both dimensions by 0.75. That preserves the original frame shape, although it reduces the available pixels. It is a different deliverable from a native 5120 × 1440 file.

Create a timeline that owns the ultrawide format

Create the custom timeline before arranging titles or reframing clips. Resolve normally makes new timelines inherit the project settings, but it also supports individual timeline settings for format, monitoring, output and color. This lets one timeline have its own dimensions without requiring every timeline in the project to share them. Reference Manual, Chapter 41: Creating and Working with Timelines

  1. Open the Edit page and choose File > New Timeline or press Command-N.
  2. Give the timeline a recognizable name, such as Ultrawide 3440x1440.
  3. Clear Use Project Settings to expose the individual settings. The manual also refers to the Use Custom Settings control in this dialog.
  4. In Format, enter 3440 for width and 1440 for height in the custom frame-size fields beneath Timeline Resolution.
  5. Choose Square for the pixel aspect ratio when working with ordinary square-pixel desktop recordings. Leave Use vertical resolution unchecked.
  6. Set the intended timeline frame rate before editing. For the worked example, assume the source recording and intended delivery are both 30 fps.
  7. Set Mismatched Resolution to Scale entire image to fit, then create the timeline.

These controls and the new-timeline procedure are documented in Chapters 6 and 41 of the Resolve 21.1 Reference Manual. To revisit an existing timeline, right-click its entry in the Media Pool and choose Timelines > Timeline Settings.

If you are using project-wide settings instead, the equivalent geometry controls are under Project Settings > Master Settings, while the default treatment of mismatched clips is under Image Scaling > Input Scaling. Check which level controls your timeline before changing values: a timeline using individual settings can differ from the project defaults. Reference Manual, Chapters 6 and 41

Frame rate deserves an early decision. Blackmagic documents that the project’s timeline frame-rate setting becomes unavailable after media is added to the Media Pool, while individual timelines provide their own format settings. Decide the intended cadence during setup rather than treating it as another width-and-height adjustment later. Reference Manual, Chapter 6

Decide how each mismatched clip should fit

An ultrawide timeline can contain footage with different proportions. The scaling choice determines whether Resolve preserves the whole source, trims its edges or changes its proportions. Blackmagic documents four input-scaling methods; the following table translates them into practical editing decisions. Reference Manual, Chapter 6: Image Scaling

Scaling method What happens When to choose it
Scale entire image to fit Preserves proportions and the whole image; unused space remains where the shapes differ Desktop recordings, slides and diagrams whose edges matter
Scale full frame with crop Preserves proportions and fills the frame; excess image extends beyond the frame Footage you can deliberately reframe
Center crop with no resizing Keeps the source at its pixel size; larger images are cropped and smaller images leave space A deliberate pixel-size workflow
Stretch frame to all corners Resizes the image independently to match both frame dimensions Material that specifically requires this treatment, rather than ordinary square-pixel recordings

For a particular timeline clip, open Inspector > Video > Retime and Scaling and change Scaling from Project Settings to the appropriate override. The available choices are Crop, Fit, Fill and Stretch. Use Fit when preserving the complete source is the priority. Reference Manual, Chapter 57: Compositing and Transforms in the Timeline

A useful starting policy is to fit screen recordings and diagrams, then decide individually whether other footage can be filled and reframed. This keeps an automatic crop from removing a menu, label or other detail needed to follow the recording.

Understand the fit-versus-fill tradeoff with one calculation

Consider an illustrative 1920 × 1080 clip inside the 3440 × 1440 timeline. The calculations below assume square pixels, centered placement and no additional transforms. They describe geometry, not a measured rendering result.

With Fit, the scale factor is the smaller of 3440 ÷ 1920 and 1440 ÷ 1080, or approximately 1.333. The clip becomes 2560 × 1440. That leaves 880 pixels horizontally, giving a centered clip 440 pixels of space on each side.

With Fill, the scale factor is the larger ratio, approximately 1.792. The clip becomes 3440 × 1935. It fills the width, but its height exceeds the timeline by 495 pixels. Centered placement therefore removes approximately 247.5 pixels from both the top and bottom of the scaled image.

This explains why a 16:9 recording cannot simultaneously fill an ultrawide frame, retain every edge and keep its proportions. Choose which requirement matters for that shot. For a desktop demonstration, preserving readable controls may justify side space; for a simple graphic, you might redesign the layout to use the wider canvas.

If you select Fill, inspect the result and adjust the clip’s position in the Inspector where needed. Positioning changes which part remains visible; it does not eliminate the geometric crop. Resolve documents its Edit-page transform and cropping controls in Chapter 57.

Keep Fusion titles and graphics at the intended size

Fusion can display a different image size from the Edit timeline without indicating an error. Blackmagic explains that Fusion compositions do not have one universal resolution: source media can establish the initial image dimensions, while generated images normally follow the relevant composition context. Fusion output then returns to the Edit timeline through Resolve’s image-sizing settings. Reference Manual, Chapter 75: Controlling Image Processing and Resolution

For example, opening a higher-resolution source clip in Fusion can expose that source resolution even when the Edit timeline is smaller. Avoid adding a 1920 × 1080 resize merely because a node viewer shows an unexpected size. First inspect the dimensions flowing through the nodes and the scaling applied when the result reaches the timeline.

For a composition combining neutral text or graphics over a background, establish the intended canvas through the background input of the Merge node. Blackmagic documents that this input determines the Merge output resolution. A Background node set to the intended frame size is a supported way to control that canvas; position and scale foreground elements within it, then inspect the result back on the Edit page. Reference Manual, Chapter 75

Export an ultrawide file and verify it on your Mac

The export dimensions are a separate checkpoint. Resolve’s Deliver-page resolution normally follows the timeline when output scaling matches the timeline settings, but a render setting can override it. Verify the actual width and height before rendering. Reference Manual, Chapter 11: Format Resolution on the Delivery Page

  1. Open Deliver and select Custom Export.
  2. Choose Single Clip for one finished movie.
  3. Select a supported output format and codec. For a conventional playback file, Resolve documents an H.264 master configuration using QuickTime and H.264; confirm that your selected encoder accepts the intended custom dimensions.
  4. Check Resolution and enter 3440 × 1440 if necessary. Verify the intended frame rate too.
  5. If the movie includes audio, enable audio export and check the output-bus selection.
  6. Choose the filename and destination, add the job to the render queue, and render a short representative section first.

Blackmagic documents the export controls, H.264 master configuration and audio output selection in Chapter 187: Rendering Media. If a selected format or encoder rejects the dimensions, choose another supported combination and repeat the short test before rendering the complete timeline.

Open the exported test in QuickTime Player, then choose Window > Show Movie Inspector or press Command-I. Apple documents this inspector as showing video information including resolution, aspect ratio, compression format and frame rate. Confirm the reported resolution is 3440 × 1440. View information about a media file in QuickTime Player on Mac

Watch the test as well as checking its metadata. Inspect the edges of a desktop recording, the proportions of a simple circle or square, title placement, and any transitions between differently shaped clips. This catches composition problems that a correct resolution alone cannot reveal.

Trace unexpected bars, cropping or stretching

Use the symptom to decide which control to inspect first. The sequence below follows the distinction Resolve makes between input scaling, clip transforms, Fusion processing and output scaling. Reference Manual, Chapters 11, 57 and 75

  • The file reports 1920 × 1080: inspect the Deliver resolution and output-scaling settings, then check the active timeline’s Format settings.
  • A 16:9 clip has side space in the ultrawide movie: check whether Fit is selected. That space is expected when preserving the whole image.
  • Edges disappear: inspect Fill scaling, Inspector zoom and cropping, and any Fusion nodes that resize or crop.
  • Circles become ovals: inspect Stretch scaling, independently adjusted horizontal and vertical zoom, and pixel aspect ratio.
  • A graphic occupies an unexpectedly narrow canvas: inspect its Fusion image dimensions and the background input controlling its Merge output.

Also check Timeline > Output Blanking if unexplained black areas remain. Blackmagic describes output blanking as a final operation that covers portions of the picture with black. Adding blanking to a 16:9 frame does not change that frame into an ultrawide pixel resolution. Reference Manual, Chapter 11: Output Blanking

Finish with three values aligned: the intended timeline dimensions, the chosen treatment of mismatched footage, and the exported file’s dimensions. Once those agree, you can make deliberate framing decisions for each clip while preserving a genuinely ultrawide deliverable.

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