How this tool works
Choose a shape and the video is redrawn into it, frame by frame, then encoded again. The live preview shows a real frame from your file in the new shape before anything is encoded, because the only way to know whether a crop works is to look at it. Nothing is uploaded — the work happens on your own device.
The size you pick is the short edge, because that is what people mean by a resolution: vertical 1080p is 1080 wide and 1920 tall. How the picture fills the new shape is the important choice, and there are three ways to do it. Blurred fill scales the whole frame to fit and puts an enlarged, blurred copy of the same frame behind it, so nothing is cropped and nothing is black. Fill and crop fills the frame completely and cuts away whatever does not fit. Fit with bars shows the whole picture on a flat colour.
Choosing how to fit
- Blurred fill is the default for good reason: it loses nothing from the picture and does not leave black bars, which is why it is what Instagram and the popular editing apps do. On a busy scene it looks deliberate rather than like a compromise.
- Fill and crop is cleaner and costs you the edges: going from widescreen to vertical throws away most of the width, so a subject standing to one side disappears. The estimate says how much is being cut, and the crop position can be moved off centre.
- Fit with bars keeps everything and looks dated: it is the right answer when the whole frame genuinely matters — a screen recording, a diagram, anything where cropping loses information rather than scenery.
- Reshaping always re-encodes: the picture is redrawn into a new frame, so there is a small quality cost. Work from the best source you have rather than from something already reshaped once.