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Comparisons are easier when both clips play at once. Drop in two to four videos to place them side by side, stack them, or arrange four in a 2×2 grid. Choose the gap, background colour, which audio to keep and how long the result runs, then render a single MP4 locally.
Processing locally on your device
Overview
A split-screen video plays several clips in one frame at the same time. With two or three videos you can choose a row (side by side) or a column (stacked). In a row, every clip is scaled to the same height, so each keeps its own aspect ratio; the height is the smallest of the clips, capped at 1080 pixels, and the total width is kept within 3840 pixels. In a column, every clip shares the same width, up to 1920 pixels.
Four videos make a 2×2 grid. Each cell takes the shape of the first video, at most 960 pixels on its long side, so four 1080p clips produce a 1920 × 1080 frame plus any gap. Clips with a different shape are fitted inside their cell with bars in the background colour. A gap of 0 to 40 pixels separates the videos, and you can reorder clips with the up and down buttons at any time.
Videos rarely have identical lengths. Shortest stops the result when the shortest clip ends; Longest runs until the longest one ends and holds the last frame of the shorter clips. For sound, pick the audio of any one video, mix all of them at balanced levels, or export silently. The preview plays all clips in sync and shows the output size and length before you render.
Rendering is done by FFmpeg 5.1 compiled to WebAssembly in your browser, with no upload. The output is an MP4 with H.264 video (CRF 21) and AAC audio, at the frame rate of the first clip (up to 60 fps). Because two to four videos are decoded at once and the combined frame is re-encoded on a single thread, a one-minute split screen can take several minutes on a laptop. The engine is a one-time, cached download of about 31 MB.
| Clips | Layout | Output size |
|---|---|---|
| 2 | Side by side | 3840 × 1080 |
| 2 | Stacked | 1920 × 2160 |
| 3 | Side by side | 3840 × 720 |
| 4 | 2×2 grid | 1920 × 1080 |
Drop two to four videos into the tool.
Reorder them with the up and down arrows.
For two or three clips, choose side by side or stacked; four clips form a 2×2 grid.
Set the gap and background colour.
Choose Shortest or Longest length and which audio to keep.
Click Create split screen and download the MP4.
Use cases
Show an original and an edited, restored or color-graded version of the same clip side by side so the difference is obvious.
Put two performers, or a performer and a reaction, next to each other in a vertical stack for TikTok-style duet videos.
Compare two golf swings, runs or lifts recorded on separate days, and use the gap to make the split clear.
Show four angles of an event, or four products doing the same task, in a 2×2 grid with a single shared soundtrack.
Pro tips
Answers to common questions about the side-by-side.
Yes. In a row or column each clip is scaled to the shared height or width and keeps its proportions. In a grid, clips that don’t match the first video’s shape are fitted with bars.
With Shortest, the output stops when the shortest clip ends. With Longest, it runs to the end of the longest clip and the others freeze on their last frame.
Yes. Choose Mix all and every clip with sound is mixed at a balanced level. You can also keep just one clip’s audio or export without sound.
No, the tool handles up to four. Decoding more videos at once would be very slow in a browser.
Every input is decoded and the combined frame is re-encoded on one CPU thread in WebAssembly. Expect several minutes per minute of output for HD clips, more on older laptops.
No. ToolEnhancer processes files on your own device inside the browser. They are never sent to, stored on or seen by our servers.
Yes. The side-by-side is free to use with no sign-up, no watermarks and no daily limits.