Add a border or frame
A border means compositing a shape around every frame, which is a layer on a timeline rather than a conversion parameter. The full editor does it — this page takes you there with your file.
Result right hereDrop a video here, or click to choose
MP4 · MOV · MKV · WebM · audio · images · subtitles · ZIP
A border is a layer sitting on top of the picture for the whole clip. Layers are what a timeline is for.
In the editor you can place a shape, size it, colour it and keep it for as long as you like.
If what you want is a different picture shape rather than a decorative frame, the "change aspect ratio" tool does that in one click right here.
FAQ
Did you mean a coloured frame or a change of shape?
If you want the video to become square or vertical, use the aspect ratio tool. A decorative frame is a layer.
Can the border be an image?
Yes, in the editor. On this site the "add a sticker" tool also places a PNG over the picture.
Does it change the video size?
A border drawn on top does not. Padding the picture out does, and that is also a timeline job.
Is there a rounded-corner option?
In the editor, yes.
Is it free?
Yes.