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Free

Video converter

Convert MOV, MKV, AVI, WebM, WMV, 3GP and MTS videos to MP4, WebM, GIF or MP3 online free. Remuxed in seconds when the codecs fit. Batch, no upload.

Convert to
Quality

When the streams already fit the new format, they are copied as they are: a fast remux with no quality loss. Otherwise the video is re-encoded at high quality.

Maximum resolution

Remux or re-encode

A video file is a container (MP4, MOV, MKV, WebM) holding compressed streams, usually H.264 or HEVC video and AAC sound. When the streams already fit the new container, Nibbo copies them as they are: a remux takes seconds even for an hour of video and loses no quality.

When they don’t fit, as with VP9 in WebM, Windows Media in WMV or Xvid in AVI, every frame is decoded and encoded again: on your graphics chip through WebCodecs, or with FFmpeg compiled to WebAssembly where the browser can’t. That takes about as long as the video plays, or longer.

How it works

  1. Drop one or many videos and pick MP4, WebM, GIF or MP3. Each file shows whether it will be remuxed or re-encoded.
  2. Remuxes copy the streams into the new container. Re-encodes run on your device with WebCodecs, or with FFmpeg compiled to WebAssembly when the browser has no suitable codec.
  3. Download each result, or all of them as one ZIP. Nothing is uploaded at any step.

Questions

Are my videos uploaded?

No. Reading, remuxing and encoding all run in this browser tab. Open DevTools and watch the Network tab while a file converts: no request carries it.

Why is one file done in seconds and another takes minutes?

A remux only copies the streams, so it runs at disk speed. A re-encode decodes and encodes every frame; FFmpeg in WebAssembly, used when the browser can’t, is slower still.

How large can a video be?

Up to 3 GB per file for free, and as many files as you like. Remuxes and WebCodecs re-encodes stream from the disk; the FFmpeg path holds the result in memory.