MKV to MP3
Extract the main audio track of an MKV video as MP3. Nothing is uploaded.
Drop MKV files here
Converted on your device. Files are never uploaded.
Up to 20 files at a time.
MKV files often hold films, recorded shows and concerts, with several audio and subtitle tracks inside. When you only want the sound, an MP3 is far easier to play on a phone or in a music app. FormatJet extracts the main audio track in your browser, so the MKV stays on your device.
About the formats
MKVMatroska video
MKV (Matroska) is an open video container that can hold several audio and subtitle tracks. Media players like VLC open it, but phones, editors and TVs often don’t.
MP3MP3 audio
MP3 is the most widely supported audio format. Its lossy compression makes music about a tenth of the size of a CD, and every phone, car and player can play it.
Converted with Mediabunny, Browser audio decoder (WebCodecs), LAME MP3 encoder, Media engine (FFmpeg).
Questions
My MKV has several audio languages. Which one becomes the MP3?
The file’s main audio track. MKVs often carry extra languages or a commentary, but an MP3 holds a single track, so only the main one is converted.
Are the subtitles kept?
No. Only sound goes into the MP3; the video and any subtitle tracks in the MKV are dropped.
Can I convert a large MKV film?
Yes, up to 1 GB. Mediabunny reads the MKV in pieces rather than loading it whole, so a long film doesn’t have to sit in memory all at once.
Which bitrate should I choose for a film soundtrack?
Start with the default, 192 kbps. If the music and effects matter to you, a higher choice in Options sounds better, and the MP3 grows with it.
MKV to MP3 with the API
The conversion API opens later this year.
curl https://api.formatjet.com/v1/convert?to=mp3 \
-H "Authorization: Bearer fj_test_…" \
-F file=@input.mkv -o output.mp3