BYTETOOLS

Side-by-Side Video Maker

Put two videos next to each other, stacked, or one inside the other as picture-in-picture. Choose which clip's sound to keep or mix both, all in your browser.

Drop the first clip hereLeft, top, or the background in picture-in-picture.
Drop the second clip hereRight, bottom, or the inset in picture-in-picture.

The result stops when the shorter clip ends. Both clips are re-encoded with H.264 on your own device, so a pair of long or high-resolution videos will take several minutes — keep this tab open while it works.

Add both clips to continue.

What is the Side-by-Side Video Maker?

The ByteTools Side-by-Side Video Maker combines two clips into one frame. Place them left and right for a comparison, stack them top and bottom for a vertical feed, or drop the second clip into a corner of the first as picture-in-picture with an adjustable size and position.

  • Three layouts: side by side, stacked, and picture in picture
  • Picture-in-picture inset placeable in any corner at 10–60% width
  • Mixed clip sizes scaled and letterboxed to line up automatically
  • Audio from the first clip, the second, both mixed, or silent
  • Landscape, vertical 9:16 and square output presets
  • 100% local processing — neither video is uploaded

How to use the Side-by-Side Video Maker

  1. 1

    Drop your first clip into the left box and your second into the right box.

  2. 2

    Pick a layout: side by side, stacked, or picture in picture.

  3. 3

    Choose an output size, and for picture in picture set the inset corner and width.

  4. 4

    Choose which clip's sound to keep, or mix both together.

  5. 5

    Click Combine clips, then preview the result and download the MP4.

About the Side-by-Side Video Maker

The ByteTools Side-by-Side Video Maker combines two clips into one frame. Place them left and right for a comparison, stack them top and bottom for a vertical feed, or drop the second clip into a corner of the first as picture-in-picture with an adjustable size and position.

It is what you want for before-and-after comparisons, reaction videos, split-screen duets, dance or workout clips shown against a reference, and gameplay with a webcam inset. Clips of different sizes are scaled to fit and letterboxed automatically, so a phone video and a screen recording still line up cleanly. You choose whether to keep the first clip's audio, the second clip's, a mix of both, or none.

Everything runs 100% locally in your browser with a WebAssembly build of ffmpeg. Neither video is uploaded anywhere. Both clips have to be decoded and the combined frame re-encoded with H.264 on your own device, so two long or high-resolution videos will take several minutes — keep the tab open while it works.

Frequently asked questions

How do I put two videos side by side?

Drop one clip into each box, leave the layout on Side by side, pick an output size and click Combine clips. Each video is scaled to fill half the frame, letterboxed if its shape does not match, and the two are joined into a single MP4.

Can I make a picture-in-picture video?

Yes. Choose the Picture in picture layout and the second clip is overlaid on the first as an inset. You can put it in any of the four corners and set its width between 10% and 60% of the frame, which covers everything from a small webcam bubble to a half-screen overlay.

What happens if my two clips are different lengths?

The combined video ends when the shorter clip does. If you want them to match, trim or loop one of them first — the Loop Video and Split Video Into Parts tools on this site can do that before you combine.

Why did mixing the audio fail?

Mixing needs both clips to actually contain a soundtrack. If one of them is silent there is nothing to mix, and the tool reports it. Switch the sound option to whichever single clip has audio and it will work.

Do the two videos need to be the same size?

No. Each clip is scaled to fit its half of the frame and padded with black where its shape does not match, so a vertical phone video and a widescreen screen recording combine perfectly well without any manual resizing.

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