WAVE MP4
Why not upload

Free online MP4 converter without the upload.

Every other converter Upload · queue · download Wave Drop · convert · save
The file Uploaded to their server Never leaves the tab
Progress bar Actually your upload speed The actual conversion
“Deleted later” You take their word for it No server = no copy to delete
File size Free tier caps or queues you 8 GB per file, no queue
Terms of service You grant a licence to your file MIT site · LGPL FFmpeg
Under the hood · real time

What a conversion actually looks like.

wave://engine · sample.mkv → sample.mp4 ready
  1. INIT engine 30 MB WASM · once per session
  2. MOUNT sample.mkv 24.3 MB · in-memory only
  3. PROBE streams 1× H.264 · 1× AAC · 1080p
  4. PLAN route streams already fit MP4 → remux
  5. REMUX container Matroska → ISO base media · no re-encode
  6. WRITE sample.mp4 24.3 MB · fast-start atom · 2.1 s
0 bytes uploaded 2.1s total 100% local
How it works

Three steps.
No upload in any of them.

  1. 01

    Drop your file

    Pick a video from your device, or drag one onto the card. Never leaves the browser.

  2. 02

    Wave runs the engine locally

    A WebAssembly build of FFmpeg does the work right here, on your machine. No queue, no wait for someone else's server.

  3. 03

    Save the result

    MP4 for video, or MP3 if you only want the audio. One click, straight to your Downloads folder.

Why Wave

The converter that respects your files.

Nothing leaves your device

Every byte stays in your browser tab. No upload, no server round-trip, no copies you can't see.

Fast when it can be

If the streams already fit MP4, Wave repackages instead of re-encoding. Same quality, seconds instead of minutes.

Free. No account. No file limits.

Convert as many files as you want. No sign-up wall, no "10 free conversions" gimmick, no watermark on the output.

Real MP4, real playback

Output ships with a fast-start atom so it plays everywhere - QuickTime, VLC, Windows, iOS, Android, the web.

Audio, too

Grab just the audio from any clip as an MP3 - same offline pipeline, one universally-playable format.

Open, LGPL-only

Built on FFmpeg's LGPL core. No GPL contamination, no closed encoders - the engine you can inspect.

FAQ

Answers, briefly.

Do you actually upload my video anywhere?

No. Wave loads a WebAssembly build of FFmpeg into your browser and runs the whole conversion locally. You can open your browser's network tab while you convert and see for yourself - no file bytes go out.

Is it really free?

Yes. No sign-up, no trial, no per-file limit, and no watermark on the output. The conversion itself always stays on your device and free to use.

How large a file can I convert?

Up to 8 GB per file. Wave streams the source through the WebAssembly engine in chunks (via WORKERFS) and, on Chrome and Edge, can save the output straight to disk with the File System Access API instead of buffering it in RAM - so the ceiling is really about your browser's decoder headroom, not file size. A warning appears above 2 GB so you know it'll take a while.

Which formats does it read?

MP4, MOV, MKV, AVI, WEBM, FLV, TS, 3GP, M4V, and most other common containers. When the input already contains H.264, HEVC, AAC, or MP3, Wave copies the streams straight into MP4 - no re-encode.

Why is my "just repackage" conversion so fast?

Because there's no encoding involved. Wave inspects the source, and if the video and audio streams already fit inside MP4, it just changes the container. The pixels and samples are untouched - same quality, a fraction of the time.

Can I extract audio from a video?

Yes. On the conversion screen, pick MP3 as the output format. Wave will pull the audio out and save it as an MP3 - one format on purpose, so it plays on any device that plays sound.