AnyTool
Your files never leave your device. All processing happens locally in your browser.

How do I make a split-screen video in my browser without uploading?

Open AnyTool's Video Split Screen tool, drop in 2 to 4 clips, and combine them side-by-side, top/bottom, or in a 2x2 grid. Mix the audio together or pick one clip's audio, then export an MP4. It runs in your browser with a self-hosted ffmpeg engine: no upload, no CDN, no watermark.

  • Combine 2-4 videos into one frame
  • Side-by-side, top/bottom, or 2x2 grid
  • Mix all audio or pick one source
  • 100% in your browser — no signup, no watermark

What is

Split-screen video

A split-screen video shows two or more clips at once within a single frame — arranged side-by-side, stacked top and bottom, or in a 2x2 grid — with audio either mixed together or taken from one source. Building it client-side composites the clips in the browser, so the files are never uploaded.

Video Tools

Related terms

split screengridside-by-sideaudio mixffmpeg

How to Make a Split-Screen Video

Combine 2-4 clips into one frame in your browser.

1 minWeb browser
  1. 1

    Add videos

    Drop in 2 to 4 clips — they stay on your device.

  2. 2

    Pick a layout

    Choose side-by-side, top/bottom or a 2x2 grid, and set the audio.

  3. 3

    Export

    Composite and download the MP4 — nothing is uploaded.

Result: A split-screen MP4 video

Frequently Asked Questions

Two to four, side-by-side, top/bottom, or in a 2x2 grid.

Two clips can go side-by-side or stacked, and three or four fit into the grid layout.

You can mix all the clips' audio together or pick a single clip's audio.

Mixing blends every track, while picking one keeps just that clip's sound in the MP4.

No — the split screen is composited entirely in your browser with a self-hosted engine.

The clips never leave your device and there is no size cap, signup or watermark.

Detailed Explanation

Methodology

How the Video Split Screen Tool Works

AnyTool builds split-screen videos entirely in the browser using a self-hosted single-threaded ffmpeg.wasm engine — the core (ffmpeg-core.js + the 32 MB wasm) is bundled from npm and served as a same-origin asset, so nothing is fetched from a CDN. Each input clip is first scaled and padded to fit its grid cell, then the cells are combined with the hstack (side-by-side), vstack (stacked), or xstack (grid) filter; audio is mixed with the amix filter over the inputs that carry sound, or you can pick a single track or none. The composite is re-encoded as H.264 video with AAC audio in an MP4. Single-threaded is deliberate: the multi-threaded core needs SharedArrayBuffer + cross-origin isolation (COOP/COEP), which would block cross-origin ad iframes, so it is avoided.

  • Runs client-side — the videos are never uploaded
  • Self-hosted ffmpeg core (bundled) — no CDN
  • Each input scaled + padded to its cell
  • Combined with hstack / vstack / xstack
  • Audio amix over sound-carrying inputs, or pick one / none; H.264 + AAC MP4
  • Single-threaded (keeps ads working); no backend, no cap
Privacy & Security

Privacy vs Upload-based Tools

Most online split-screen makers upload your files to a server and cap the free tier or add a watermark. AnyTool composites locally with a bundled engine, so the videos never leave your browser, there is no size limit, no watermark and no signup, and it works offline after the first load.

Split screen: AnyTool vs typical tools
CapabilityAnyToolTypical tools
Data handlingIn your browserOften uploaded
Engine sourceSelf-hosted (no CDN)CDN / server
Layoutshstack / vstack / xstackOften fixed
Audioamix / pick / noneOften first only
Watermark / capNoneCommon
CostFree, no signupFree/limited

AnyTool is a privacy-first client-side split-screen maker — compositing runs locally and nothing is uploaded.