How cropping works here
Load a video, then drag a rectangle across the preview to mark the region you want to keep. An aspect preset row above the preview offers Freeform, 1:1, 4:3, 16:9, and 9:16. Choosing one constrains the drag, so the selection keeps that shape however you move it, which is the difference between hitting a square exactly and getting one that is four pixels off.
When you export, the region outside the rectangle is discarded and the remaining picture is re-encoded to MP4 with H.264 video and AAC audio. Cropping is a real change to the picture, so it cannot be done without re-encoding: the frame dimensions themselves are different afterward.
The crop dimensions are rounded to even numbers because H.264 requires it. That means the exported frame can be a pixel narrower or shorter than the rectangle you drew, which never matters visually and occasionally matters if you are matching an exact size.
- Load a video and pick an aspect preset
- Drag the selection over the region to keep
- Export and download the cropped MP4
Choosing an aspect ratio
The presets exist because most cropping is done to hit a required shape rather than to reframe artistically. 9:16 is the vertical shape used by phone-first video surfaces. 1:1 is the square that behaves predictably in a feed. 16:9 is standard widescreen, and 4:3 is the older television shape that still appears in presentation software and some embed contexts.
The important thing to understand is that cropping to a new shape means throwing away picture, not rescaling it. Turning a 16:9 landscape clip into 9:16 vertical keeps a narrow column from the middle and discards most of the width. If the action in your footage moves across the frame, it will walk out of that column.
Freeform is there for the other case, where you are cutting out a black border, removing a watermark from an edge, or isolating one region of a screen recording. In that mode the selection is whatever you drag.
Cropping, resizing, and rotating are different jobs
These three get confused constantly and doing the wrong one wastes an export. Cropping removes part of the picture and changes the frame dimensions. Resizing keeps the whole picture and changes how many pixels it occupies, which is Video Resizer. Rotating turns the whole frame, which is Rotate Video.
If your goal is a smaller file, resizing is usually the better tool, since it keeps everything in shot. If your goal is a specific shape for a specific destination, cropping is right. If a landscape clip needs to become vertical without losing the sides, neither one does that: you need a resize with padding, which Video Resizer offers through its fit mode.
On size, everything runs in browser memory, so the whole video has to fit. Files up to around 1.5 GB are workable and larger ones can fail partway through a run. Trimming a long recording down first with Video Trimmer is the reliable route.
- Crop to change the shape, resize to change the pixel count
- Use Video Resizer with padding to fit a shape without cutting
- Trim very large files first, since everything runs in memory