Video Format Converter

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Convert video files between MP4 and WebM formats entirely in your browser. Processing uses hardware-accelerated WebCodecs decoding for fast, high-quality output without any file uploads. Your video never leaves your device.

How to Convert a Video

01

Upload a video file (MP4, WebM, MOV, AVI, or MKV)

02

Select the output format — MP4 for universal compatibility, WebM for web use

03

Click Process and download the converted file

MP4 vs WebM — which format to choose

MP4: Universal compatibility — works on every device, browser, and platform
MP4: Uses patented H.264/H.265 codecs — not fully open-source
WebM: Open format, royalty-free, excellent for HTML5 web video
WebM: Limited support on older devices, Apple ecosystem, and some media players

Common video conversion use cases

  • Convert a MOV file from iPhone or Mac to MP4 for sharing on Windows or Android
  • Convert MP4 to WebM for embedding in an HTML5 video element
  • Re-wrap AVI or MKV files into MP4 for social media upload compatibility
  • Convert WebM screen recordings to MP4 for use in video editing software
  • Prepare video files for platforms that require a specific container format

Key Features

MP4 and WebM Output

Convert to MP4 for maximum device and platform compatibility, or WebM for open-format web delivery with smaller file sizes.

Hardware-Accelerated Processing

Uses the WebCodecs API for GPU-assisted decoding and encoding, significantly faster than software-based WASM conversion tools.

Broad Input Support

Accepts MP4, WebM, MOV, AVI, and MKV input files. Any common video format can be converted to your target output.

No Upload Required

All conversion happens locally in your browser. No server, no wait time, no privacy risk — files never leave your device.

Complete Privacy

Video files are processed entirely in your browser. No data is transmitted to any server at any point during conversion.

Frequently Asked Questions

Which format should I convert to?

Choose MP4 if you need the file to work everywhere — phones, TVs, social media, video editors, and email all support it. Choose WebM if you are delivering video on the web and want an open format with good compression, particularly for use in HTML5 video players.

Will the quality change after conversion?

The output quality depends on the source. Converting from a high-quality source will produce a good result. Re-encoding always involves some generation loss compared to the original, though at the default settings this is minimal and not perceptible for most use cases.

Can I convert MOV or AVI files?

Yes. MOV, AVI, and MKV are all accepted as input. They will be decoded and re-encoded into your chosen MP4 or WebM output format.

Is there a file size limit?

The tool enforces a 500MB limit. Large files are handled with streaming I/O to keep memory usage manageable.

Which browsers are supported?

Chrome 94+ and Edge 94+ are fully supported. Firefox has partial WebCodecs support. Chrome is recommended for best performance and compatibility.