Convert MP4 to OPUS online
Free, no sign-up, no limits. Drop your MP4 files, get OPUS files back in seconds.
1 files converted so far
Drop your MP4 files here
or · multiple files accepted
Local conversion: your files never leave your device.
Why convert MP4 to OPUS?
You want to keep only the sound of a video: lecture, concert, course, interview, the music from a clip. The resulting file is 10 to 20 times smaller and plays on any player.
How to do it, step by step
- Drop your MP4 fileinto the area at the top of the page (or several files at once). On mobile, tap the area and pick the file from your apps.
- Check the output format: OPUS is already selected. For music, 192 kbps is transparent for most listeners and 320 kbps gives the maximum. For voice (memos, podcasts, lectures), 128 kbps is more than enough and halves the file size.
- Start the conversion.The FFmpeg engine loads once (≈ 10 MB), then each file is processed in a few seconds without leaving your device.
- Download your OPUS, directly or as a .zip if you converted several files. The name and metadata (title, artist, cover art) are preserved.
The MP4 format (MPEG-4 (video audio track))
MP4 is a video file. Extracting its audio track lets you keep only the sound of a lecture, a concert, an interview or a personal video, in a much smaller file you can listen to anywhere.
- Universal video format
- Large
- Pointless when only the sound matters
The OPUS format (Opus Interactive Audio Codec)
Opus is currently the most efficient audio codec: it delivers the best possible quality at very low bitrates. It is the format of WhatsApp, Telegram and Discord voice messages and of video calls. Excellent, but still poorly recognized by consumer players and car stereos.
- Exceptional quality at low bitrates
- Free format
- The standard for voice on the internet
- Very few devices play it
- Often impossible to open on Windows without extra software
MP4 vs OPUS comparison
| MP4 | OPUS | |
|---|---|---|
| Compression | Lossy | Lossy |
| Typical size (1 min, music) | ≈ 20–100 MB | ≈ 0.7 MB |
| Common use | smartphone videos, lectures, concerts, online courses | WhatsApp/Telegram voice messages, Discord, calls |
| Metadata (title, cover art) | Yes | Yes |
Frequently asked questions
Does converting MP4 to OPUS lose quality?
OPUS is a lossy compressed format: a conversion always involves re-encoding. At 192 kbps or higher, the difference is inaudible in the vast majority of cases. Just avoid chaining several successive conversions.
Is the MP4 to OPUS converter free?
Yes, with no limit on the number of files, no sign-up and no watermark. Each file can be up to 200 MB.
Are my MP4 files uploaded to the internet?
No. The MP4 to OPUS conversion is performed by FFmpeg directly in your browser (WebAssembly). Your files never leave your computer or phone.
How do I convert MP4 to OPUS on iPhone or Android?
Open this page in Safari or Chrome, tap the drop area, select your MP4 file (from Files, Voice Memos, Downloads or WhatsApp), then tap "Convert". The OPUS downloads to your files.
Can I convert several MP4 files at once?
Yes, add all your files in one go. They are converted one after another and a button lets you download everything as a .zip archive.