Combine Videos Side by Side or Stacked

How to use it#

Drop two videos onto the box above, or click it to choose them. The first goes on the left, or on top.
Choose side by side or stacked, whether the result runs as long as the longer clip or the shorter, and whose sound to keep. The arrows on a row swap the two clips.
The video is made as soon as the clips and settings settle. Play it in the preview, then download it.

How the two clips are fitted together#

Side by side, both clips are brought to the same height, the shorter clip's, so neither is enlarged and neither is cropped or given bars: a portrait phone video next to a landscape one simply takes less of the width. Stacked, both are brought to the same width instead. Each clip keeps its own shape, and the result takes whatever shape the two make together.

The result is then scaled down, if it needs to be, to the pixels of one 1080p frame. Two 1080p clips side by side would make a frame 3840 pixels wide, which takes four times as long to encode, plays badly on older phones, and is more than some browsers can encode at all, so they come out at 2712 by 762 instead. Two portrait phone clips side by side make a landscape video of 1524 by 1356.

Length, frame rate, and sound#

The two clips start together. When the result runs as long as the longer clip, the shorter one shows its last frame for the rest, or its first frame, or black, whichever you choose; set the length to the shorter clip and the result ends when either does. The frame rate is that of the faster clip, up to 60 frames a second, so neither loses frames.

Keep one clip's sound, mix both, or have none. A clip's sound that is AAC, as phones record it, is copied in as it is. Mixed sound is encoded as AAC, with each clip turned down a little so the two together do not distort. The picture is always encoded again as H.264, since the two clips have to be drawn into one frame. That is slower than copying, and slower again on an older phone or with 4K clips, but on a recent computer a minute of video takes well under a minute.

Frequently asked questions#

How do I make a split screen video?

Drop the two clips on this page and choose Side by side for a left and right split, or Stacked to stack them vertically, top and bottom. The result is ready to download once it appears in the preview.

Can I combine a portrait video with a landscape one?

Yes. Side by side, both are scaled to the same height, so the portrait clip is narrower and nothing is cropped or stretched. Stacked, both are scaled to the same width, so the landscape clip is shorter.

What happens when one video is shorter?

By default the result runs as long as the longer clip, and the shorter one holds its last frame until the end. Under Once the shorter one ends, you can show its first frame instead, or black. Choose Shorter clip to end the result when the shorter one ends.

Can I put more than two videos together?

Not at once. This page combines two. For a grid of four, combine two pairs here, then put the two results together stacked. To play clips one after another instead, use merge videos.

What size is the combined video?

Up to the pixels of one 1080p video, about two million. Clips smaller than that keep their size; larger ones are scaled down together. The Picture figure shows the exact size before you download.

Can I make a side by side video on an iPhone or Android phone?

Yes, in the browser on either. A video from the iPhone Photo Library is handed to the page as a converted copy, which works the same way. A phone encodes more slowly than a computer, so keep the page open until the preview appears.

Why is it slow?

The two clips are drawn into one frame, so every frame of the result is encoded again and nothing can be copied. Your file never leaves your device, so the work is done by your own computer or phone, inside this browser tab, not on a server built for it. Every frame is decoded and compressed again: a minute of 1080p at 30 frames a second is 1,800 pictures of about two million pixels each, and 4K has four times as many pixels. The browser hands the compression to your device's video chip where it has one, but each frame still passes through the tab, which shares the processor with everything else that is open. A phone also slows itself down as it warms up, and some browsers slow a tab you switch away from, so keeping this tab in front, closing other tabs, and plugging a phone in all help.

Are my videos uploaded?

No. Both videos are read and drawn together inside this browser tab, and the MP4 is handed straight to your downloads. Nothing is sent to a server.