About OPUS Files
Opus Audio
Opus is a versatile, open-source audio codec optimized for both speech and music at very low bitrates. It is the standard for WebRTC voice calls and excels at real-time communication.
Family
Audio Files
Extension
.opus
MIME Type
audio/opus
Can Use As
4F 50 55 53 00 01 00 00 4B 41 49 4A
ASCII: OPUS....KAIJ
📈 Target Minimum File Size (Guaranteed ≥ KB)
Lossless JPEG Q100 + standard COM segment padding for government & exam portals
Tap to choose your file Drop files here or click to browse
Automatic format identification and lossless transcoding across 201+ formats.
Convert to:
Detecting available formats...
Target Max File Size:
Uploading...
Processing your file...
READY!
Download File
Your file is converted & verified! Unlock instant download:
One-time secure payment via Stripe (Apple Pay, Google Pay, Card). Zero recurring subscription.
🛡️ Verification Audit
- ✓
- ✓ sRGB Color Fidelity
- ✓
Continue with this converted file (0s zero re-upload):
Batch Conversion Ready!
Your file is converted & verified! Unlock instant download:
One-time secure payment via Stripe (Apple Pay, Google Pay, Card). Zero recurring subscription.
Need to convert larger files or bigger batches right now?
Unlock up to 1 GB & priority cloud queue with 1-click Stripe checkout (Apple Pay, Google Pay, Card):
HOW OPUS CAME TO BE.
Opus is what happens when several of the best codec teams on the planet decide to collaborate. The IETF standardized it in September 2012 (RFC 6716) as a unified successor to Vorbis, CELT, and Skype’s SILK. Its brief was audacious: one codec that beats MP3 for music, HE-AAC for low bitrates, and G.722 for voice — at every bitrate from 6 kbps to 510 kbps, with algorithmic latency as low as 5 ms.
It succeeded. Every major VoIP system (WhatsApp, Signal, Discord, Zoom, Microsoft Teams), most browser-based real-time communication (WebRTC), YouTube’s VP9 streams, and most Bluetooth LE audio devices now use Opus. The codec is entirely royalty-free. It is, quantitatively, the best general-purpose audio codec available in 2026.
Technical Specifications
- MIME type
- audio/opus
- Extensions
- .opus, .ogg (container)
- Standard
- RFC 6716 (2012)
- Sample rates
- 8, 12, 16, 24, 48 kHz
- Latency
- 5-60 ms (configurable)
Typical Sizes & Weights
Voice call (24 kbps)
180 KB/min
Podcast (48 kbps)
21 MB/hour
Music (128 kbps)
~1 MB/min
High-fidelity music (160 kbps)
~1.2 MB/min
STRENGTHS & LIMITATIONS.
Strengths
- Best-in-class quality across the entire bitrate range.
- Royalty-free and patent-free.
- Ultra-low latency — suitable for live voice and music.
- Handles speech and music equally well — no need to switch codecs.
- Mandatory codec in WebRTC, so supported in every browser by design.
Limitations
- Very low hardware decoder adoption — software-only on most phones.
- Older platforms (legacy Windows apps, old cars) may not play .opus files.
- Container semantics confusing — Opus lives inside Ogg, WebM, or MP4.
- Encoder tooling is less polished than AAC's commercial ecosystem.
CURIOSITIES & TRIVIA.
Opus can switch on the fly between a speech codec (SILK) and a music codec (CELT) mid-stream, picking the best for the current audio.
At 64 kbps, Opus sounds better than MP3 at 128 kbps — half the size, better quality.
The codec is used by WhatsApp, Signal, Discord, Telegram, Zoom, and Microsoft Teams for voice calls.
WebRTC (browser video calls) requires Opus as a mandatory codec for audio — every browser supports it.
Opus encoding latency can be as low as 5 ms — faster than human audio perception, which is why it works for live calls.
Specialized Utilities for .OPUS Files
MP3 Audio Compressor — Reduce MP3 File Size
Compress MP3, WAV, M4A, and FLAC audio files by adjusting bitrate (64k, 96k, 128k, 192k), sample rate, and mono/stereo channels.
Online Audio Cutter & Trimmer
Trim MP3, WAV, FLAC, M4A, and OGG audio tracks to exact start and end timestamps with built-in browser playback and custom bitrate.
Extract Audio from Video
Extract the audio track from any video file and save it as MP3, WAV, or other audio formats. Perfect for creating podcasts, music rips, or voice-only recordings.
Video to MP3 Audio Extractor
Extract high-bitrate MP3 audio tracks from MP4, MOV, MKV, AVI, and WebM video recordings in seconds—ideal for podcasts, lectures, and interviews.
CONVERT FROM OPUS
CONVERT TO OPUS
Common Use Cases
VoIP calls, WebRTC, voice chat, low-bitrate streaming.
Related Formats
Popular comparisons
OPUS vs MP3
Differences, file size, and when to choose each format.
OPUS vs WAV
Differences, file size, and when to choose each format.
OPUS vs FLAC
Differences, file size, and when to choose each format.
OPUS vs M4A
Differences, file size, and when to choose each format.
OPUS vs OGG
Differences, file size, and when to choose each format.
OPUS vs AAC
Differences, file size, and when to choose each format.
Popular OPUS conversions
The most-requested destinations when starting from OPUS.
Frequently Asked Questions
OPUS (Opus Audio) is an audio file format used to store sound recordings — music, voice, podcasts, sound effects. The format defines how the audio samples are compressed (or stored raw), what bitrates are supported, and how metadata such as title, artist, album, and cover art is embedded. It is part of the audio files family.
VLC, foobar2000, and the default media players on Windows and macOS handle OPUS natively. On mobile, iOS Music and Android media apps vary in their support — popular formats work everywhere; niche ones may need a dedicated app. If playback fails on a device, converting to MP3 or AAC usually solves it.
Upload the OPUS to KaijuConverter and pick MP3, WAV, FLAC, AAC, OGG, or any other target. Our FFmpeg pipeline decodes the audio and re-encodes to the target format at sensible default bitrates (VBR ~190 kbps for music, 96 kbps for speech). Metadata and cover art travel with the audio where both formats support them.
OPUS can be lossy or lossless depending on the specific variant. Lossy variants (smaller files) discard some audio detail during compression in ways tuned to be inaudible; lossless variants preserve every sample exactly but produce larger files. For distribution, lossy at high bitrate is standard; for archival, lossless wins.
Need to Convert Gigabyte Archives or Mass Folders?
KaijuConverter delivers ultra-fast in-memory conversions for everyday tasks. For multi-gigabyte production workloads without browser bandwidth bottlenecks, explore high-throughput desktop suites.
One-time payment with zero recurring commitment: convert files up to 1 GB, OCR, PDF/A, and .ZIP batches for 24 hours.
Full 7 days of unlimited conversions, up to 2 GB per file, 100% ad-free with zero subscription.
High-throughput enterprise pipeline for files up to 2,048 MB, 50-file batches, ISO PDF/A, and priority processing.
Convert thousands of camera RAW files (CR3, NEF, ARW) to WebP, AVIF, or TIFF in one pass.
GPU-accelerated RAW development with end-to-end 16-bit ICC color profile management.