Video Converter

Convert MP4, WebM, MOV, MKV between containers and codecs entirely in your browser. Hardware-accelerated via WebCodecs.

What it does

Pick a video, choose the target container (MP4 or WebM) and codec (H.264, H.265, VP9, AV1), and the encoder produces a new file without uploading anything.

When the source and target codecs match, the tool routes through a fast no-re-encode path that just remuxes the bytes into the new container.

Format quick guide

MP4 with H.264 is the universal pick — plays everywhere. H.265 is smaller for the same quality but not every device decodes it natively.

WebM with VP9 is the modern web default. AV1 produces the smallest files but encoding is slow on older hardware.

How to use it

  1. Drop a video — Drag the file in or click the dropzone. Any common video format is accepted.
  2. Pick format and codec — MP4/H.264 for compatibility, WebM/VP9 for the web, MP4/H.265 to halve the file size on modern devices.
  3. Download — The encoder runs locally; the new file lands on your machine as soon as it finishes.

When to use it

Phone footage to a web-friendly file

Convert HEVC iPhone clips to MP4/H.264 so Windows and old browsers can play them without re-encoding through the cloud.

Codec shopping

Compare H.265 vs VP9 vs AV1 sizes on your actual content before committing a transcoding pipeline to one codec.

Container changes only

MOV → MP4 with the same H.264 codec is instant — no re-encode, no quality loss.

FAQ

Will my video upload anywhere?
No. WebCodecs runs the encoder inside your browser tab. Verify in the network panel: zero bytes leave your device during a conversion.
How large can the input be?
There's no hard cap. Files past 500 MB transparently stage to OPFS so the browser doesn't try to hold the whole blob in RAM.
Does it preserve quality?
Lossless re-mux when codecs match. Otherwise lossy — pick a quality preset that suits your bitrate budget.