H5Kit

Convert Video

Free online video converter: turn common video formats into universally playable MP4 (AVC + AAC) or compact WebM (VP9 + Opus). Converts locally in your browser — no upload.

About this tool

Convert videos between formats entirely in your browser. Input can be any format your browser can decode (MP4, MOV, WebM, MKV and more); output is either MP4 (AVC + AAC) for maximum compatibility or WebM (VP9 + Opus) for smaller files on the web.

How to use

  1. Click or drag to select a video file
  2. Preview the video to confirm it decodes correctly
  3. Choose the target format (MP4 or WebM)
  4. Click "Convert" and download the converted video

FAQ

Should I choose MP4 or WebM?

MP4 (AVC + AAC) plays on virtually every device, phone and TV — pick it when in doubt. WebM (VP9 + Opus) is usually smaller at the same quality and great for websites, but some older devices and players do not support it.

Which input formats are supported?

Anything your browser can decode: MP4, MOV, WebM and MKV work in all major browsers. If a file cannot be read, the tool will let you know.

Will quality get worse after conversion?

Converting always re-encodes the video, which trades a little quality. The default settings aim for a good balance, and for most footage the difference is barely visible.

Are my videos uploaded to a server?

No. All decoding and encoding runs locally in your browser. Your files never leave your device.

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