resize video without stretching

The resize operation always preserves your source video's original aspect ratio. Internally, it scales the footage to fit entirely within your target width and height (whichever dimension is more restrictive), then centers it and fills any remaining space with black bars. There is no code path in this tool that stretches width and height independently to force-fill a mismatched frame — that kind of distortion simply isn't possible with the resize settings here.

This is different from some resize tools (including some video editing software's default behavior) that stretch footage to exactly fill a target frame, distorting circles into ovals and faces into stretched or squeezed versions of themselves. If you've been burned by that kind of result elsewhere, this tool's fit-and-pad approach is the safer default.

The trade-off is that a target size with a very different aspect ratio than your source will produce black bars rather than a full-frame fill. If black bars aren't acceptable for your use case and you specifically want the frame filled edge-to-edge, that requires cropping into the footage instead — the site's Crop Video tool handles that case by letting you choose exactly which region of the frame to keep.

For most resizing needs — downscaling for a smaller file, standardizing several clips to one resolution, preparing a video at a specific pixel size a platform requires — the fit-and-pad approach is exactly what you want, since it guarantees the footage always looks correctly proportioned, just possibly with black bars if the shapes don't match.