Convert WebM to MP4
Convert your WebM videos to MP4 format. Processed locally in your browser.
Drop your file here
Related tools
Convert a video in your browser
Filzy lets you convert a video to switch WebM to MP4 for compatibility with Windows, Office, social platforms and the wider ecosystem. The tool runs ffmpeg.wasm directly inside your browser tab, so your video file is decoded and re-encoded on your CPU without ever uploading to a server. The output is a re-encoded MP4 with H.264 video and AAC audio, opens cleanly in Office, social platforms and legacy players. Filzy supports WebM as input. The free tier processes 3 files without an account; signing up unlocks unlimited use, with no daily cap and no watermark.
Files stay on your device
Decoding, processing, and re-encoding all happen in a Web Worker via ffmpeg.wasm. The video bytes never reach a server, no temporary copy is stored anywhere.
Local CPU speed
WebAssembly delivers near-native performance on your CPU. A 5-minute clip typically processes in 1 to 3 minutes on a modern laptop, depending on the operation.
No upload, no daily cap
Skip the multi-minute upload that plagues server-based tools. The bottleneck moves to your CPU, where you have full control. No daily limit, no watermark.
How to convert a video with Filzy
- 1
Drop your video
Drag the file in, or click to select. Filzy accepts WebM files. The practical size limit is your device memory; multi-gigabyte files work on most modern laptops.
- 2
Filzy converts the video locally
ffmpeg.wasm decodes the video, applies the operation, and writes the result. Progress is shown frame by frame in the browser. The output is a re-encoded MP4 with H.264 video and AAC audio, opens cleanly in Office, social platforms and legacy players.
- 3
Download the result
Save the file, or send it straight to another Filzy tool such as Compress, Trim, or Add watermark. Files chained between Filzy tools also stay local.