WebM to MP3
Convert the audio in WebM files to MP3. Nothing is uploaded.
Drop WebM files here
Converted on your device. Files are never uploaded.
Up to 20 files at a time.
WebM is common for browser recordings, screen captures and video saved from the web, but music players and audio editors often don’t open it. Converting to MP3 gives you audio that plays almost anywhere. FormatJet does it in your browser, so the file stays on your device and nothing is uploaded.
About the formats
WebMWebM video
WebM is an open video format made for the web, with VP8, VP9 or AV1 video and Opus or Vorbis audio. Browsers play it, and screen recorders often save it.
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
What audio is inside a WebM?
Usually Opus, sometimes Vorbis. Your browser decodes either one with its built-in decoder, and FormatJet then encodes the result as MP3 with LAME.
Does the MP3 sound as good as the WebM?
It can’t sound better, and it may lose a little. Opus and Vorbis are lossy already, so making an MP3 is a second round of lossy compression; a higher bitrate in Options holds on to more than the default 192 kbps.
What about a screen recording with no sound?
A WebM without an audio track can’t become an MP3, so the page refuses it and says the file has no audio. Check that the recording captured sound, then record it again.
Can I convert several WebM files at once?
Yes, up to 20 at a time. The MP3s download one by one or together through “Download all”, each named after its WebM.
WebM 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.webm -o output.mp3