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MP4 to Opus Converter — Free, Online, No Upload

Extract and compress the audio from an MP4 to Opus — perfect for streaming the soundtrack at minimal bandwidth.

Free · no signup2 free files a day100% in-browser · no upload

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How to convert MP4 to OPUS online

  1. 1

    Drop your MP4 file

    Drag your MPEG-4 Part 14 file onto the box above, or click it to pick a file.

  2. 2

    Wait a few seconds

    Conversion starts on its own and runs on your device, not on a server.

  3. 3

    Download your OPUS

    Click Download to save the Opus Interactive Audio Codec file.

MP4 vs OPUS: format overview

MP4

MPEG-4 Part 14

Moving Picture Experts Group · 2001

Compression
lossy
Transparency
No
  • ✓ Universal compatibility across all platforms
  • ✓ Excellent compression with H.264/H.265
  • ✗ H.264 has royalty implications
OPUS

Opus Interactive Audio Codec

IETF / Xiph.Org · 2012

Compression
lossy
Transparency
No
  • ✓ Best low-bitrate quality of any audio codec
  • ✓ Royalty-free and open standard (RFC 6716)

MP4 magic bytes: 00 00 00 xx 66 74 79 70

OPUS magic bytes: 4F 67 67 53 (Ogg container)

Why convert MP4 to OPUS?

You've got a video — a recorded meeting, a podcast video, a voice memo captured as MP4 — and you need to deliver the audio over the internet with the smallest possible file size. MP3 is old technology. AAC is patented. Opus is the modern answer: a royalty-free codec engineered specifically for streaming, VoIP, and web delivery, and it outperforms both MP3 and AAC at every bitrate below 128 kbps.

This converter extracts the audio from your MP4 and re-encodes it as Opus. Discord uses Opus for voice. WebRTC (the technology behind browser-based video calls) uses Opus. Chromium-based browsers play Opus in HTML5 audio elements natively. For a recorded meeting at 48 kbps or a music track at 96 kbps, Opus produces cleaner audio than MP3 at twice the bitrate — making it ideal for podcast streaming, web audio, and Discord bots.

Because the MP4's AAC audio is re-encoded into Opus, there is a generation loss. The converter writes 192 kbps, which keeps that loss small. The output file is a standard .opus container that plays in Chrome, Firefox, Edge, Android, and VLC. Apple's Music app doesn't play Opus, and support in Safari depends on the version.

Quality & file size: MP4 to OPUS

Typical sizes: MP4 100–300 MB (1 minute 1080p); OPUS 1–3 MB (3-minute song).

OPUS output is encoded at 192 kbps.

Re-encoding one lossy format into another adds a second round of compression.

Frequently asked questions

What bitrate is the Opus file?
192 kbps at 48 kHz, set by the converter. That is far more than speech needs — 32–64 kbps is plenty for voice — and comfortably clean for music, so a voice-only file is bigger than it has to be.
Can I play Opus files on my phone?
Android supports Opus natively. On iPhone, Opus playback requires a third-party app like VLC — the native iOS Music app does not support Opus.

Your MP4 file never leaves this tab — FormatDrop has no endpoint that receives file data. How it works