MKV to MP3

What this does

MKV is Matroska: an open container designed to hold almost anything — several video tracks, several audio tracks, subtitles in a dozen languages, chapters and attachments, all in one file. It is what film archives and fan releases use, and it is the container most likely to hand you a choice you did not know you had.

An MKV holds video alongside the sound, and often more than one soundtrack. This takes an audio track out and leaves the picture behind.

The container that usually has more than one soundtrack

Where an MP4 normally carries one audio track, an MKV frequently carries several: an original language and a dub, or a film and its commentary. This takes one of them — the track a player would select by default. The audio inside is usually AAC, AC-3 or DTS, all of them lossy, so encoding to MP3 is a second pass and 192 kbps or above keeps it inaudible. If your MKV is a music file rather than a video, the picture track simply is not there and nothing is discarded but the wrapper.

Nothing is uploaded

The conversion happens inside this page. Your file is read by the browser, converted here, and saved straight back to your downloads. It is never sent to a server, so there is no upload wait and no size cap beyond what your own device can hold.

Open your browser’s developer tools, switch to the network panel, and convert a file. You will see the converter itself download once, and no upload of your audio at all. That is the whole difference between this and a site that converts on a server, and what that difference actually means is worth a read.

The first conversion is slower

The converter is about 32 MB and downloads the first time you use it, which is the one moment this page is not instant. After that it is cached, and later conversions start immediately, even offline. So do later visits.

Questions