rndlabs / convert

webm → mp4 · marry audio · everything stays in your browser
drop files here or click to pick
a video (.webm or .mp4) · optionally a song (.mp3 / .wav) to marry in
First run downloads the ffmpeg engine (~31 MB, cached after). Conversion runs entirely on your machine — nothing is uploaded. webm → mp4 re-encodes to H.264 (crf 18); an mp4 with a song marries losslessly (-c:v copy). Made for LT64 / MCT64D renders, works on anything.