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Convert Video Files Locally in Your Browser

The browser runs the encoder directly, so there is no upload to a server.

  • Uses the WebCodecs API so the browser runs the encoder directly
  • Conversion runs in your browser, using local encoding paths when the browser exposes them
  • Works best on recent desktop browsers; mobile support varies
  • No install, no account
  • MP4, MOV, MKV, and WebM in and out

Overview

"Browser-based" used to mean "uploads to a server, server does the work, sends the result back." That is not what is happening here. This converter uses the WebCodecs API, a relatively new browser interface that lets the page run video encoding and decoding directly in the browser, on your device.

The practical effect: encoding can be quick on supported codec paths because the browser drives the encoder directly rather than uploading to a server. Performance depends on your browser, OS, and hardware.

Desktop browser support is good in recent Chrome, Edge, Opera, and Firefox; Safari has been adding fuller WebCodecs support over recent versions. Mobile browser support is improving but not yet uniform, so desktop is the recommended path for serious batch work.

Technical notes

WebCodecs

WebCodecs is a low-level browser API for encoding and decoding video frames. It lets the page run the encoder in the browser directly, which is why browser conversion can be quick for common codecs.

Hardware acceleration when available

When the browser exposes a hardware video encoder, encoding can be substantially faster than software-only encoding. Without hardware encode, the same job still runs; it just takes longer.

Browser support

Recent desktop versions of Chrome, Edge, Opera, and Firefox support WebCodecs. Newer Safari versions add fuller support. Mobile browser support is improving but not uniform; desktop is the recommended path for batch work.

Good to know

Hardware encode availability varies

Whether the browser uses a hardware encoder depends on your OS, GPU, and browser version. Without hardware encode, the same conversion still works; it just takes longer.

Mobile support is partial

Mobile browser WebCodecs support is improving but lags desktop. For one-off conversions on a phone, recent Chrome and Safari work in many cases; for serious batch work, use desktop.

HEVC depends on the browser

HEVC (H.265) decode and encode availability vary by browser and OS. H.264 is the most reliable common path; HEVC works on Safari 16.4+ and recent Chrome/Edge with hardware HEVC support.

How to convert videos in the browser

Encode your videos using the browser's built-in WebCodecs API rather than a server.

01

Add your videos

Drag and drop your video files into the converter, or click to pick them.

02

Choose your settings

Pick the output format, quality, optional width, and whether to remove audio.

03

Start the batch

Click Convert files. Each file is processed locally on your device.

04

Download

Download files individually, or grab the whole batch as a ZIP.

Frequently Asked Questions

Are my files uploaded anywhere?

No. Encoding runs in your browser via WebCodecs and the file stays on your device.

Does this work on Mac, Windows, Linux and Chromebook?

Yes, on a recent desktop browser. Performance varies with your device, browser, and the source files.

Why is encoding fast in the browser now?

WebCodecs lets the page run the encoder directly in the browser instead of round-tripping the file to a server. When the browser exposes a hardware video encoder, encoding can be substantially faster than software-only paths.

Does this work on mobile browsers?

Partially. Mobile WebCodecs support is improving but is not as uniform as desktop. Use Chrome or Safari on iOS/Android for one-off conversions; desktop is the recommended path for batches.

Why don't I need to install anything?

The encoder is already in your browser. The page just provides the UI and tells WebCodecs what to do with each file.

Which browsers does this work in?

Conversion uses the WebCodecs API. Fully supported: desktop Chrome 94+, Edge 94+, Opera 80+, Firefox 130+, and Safari 26+. Safari 16.4 to 25 work for most files but some may fail because their WebCodecs implementation is partial. Browsers without WebCodecs (Chrome/Edge <94, Firefox <130, Safari ≤16.3, Internet Explorer) cannot run the converter at all. Mobile browser support is improving but inconsistent, so a desktop or laptop is recommended for batch work.

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