Convert MKV to Opus Online Free
Extract the audio from your Matroska MKV video and encode it as Opus — the modern open codec with best-in-class compression efficiency. Ideal for streaming, Discord bots, and open-source projects.
ChangeThisFile extracts audio from your Matroska MKV video and encodes it as Opus using FFmpeg on our secure servers. Opus delivers excellent audio quality at very low bitrates, making it ideal for streaming and bandwidth-sensitive applications. Files are auto-deleted, free with no signup required.
Convert Matroska to Opus
Drop your Matroska file here to convert it instantly
Drag & drop your .mkv file here, or click to browse
Convert to Opus instantly
Matroska vs Opus: Format Comparison
Key differences between the two formats
| Feature | MKV (Matroska) | Opus |
|---|---|---|
| Type | Open video container | Open audio codec in OGG container |
| Developer | Matroska.org | Xiph.Org / IETF RFC 6716 |
| Audio codec | AC-3, DTS, AAC, FLAC, PCM, etc. | Opus — highly efficient open codec |
| File size | Large (HD video included) | Very small — best-in-class compression |
| Quality at low bitrate | Source-dependent | Excellent even at 32–64 kbps |
| License | Open-source | Open-source, royalty-free |
| Use case | HD media library | WebRTC, Discord, streaming, low-bandwidth apps |
When to Convert
Common scenarios where this conversion is useful
Create compact audio from large HD MKV files
Opus at 128 kbps provides near-transparent quality at roughly 1MB per minute. Extract audio from large HD MKV media files as Opus to create tiny, high-quality audio versions for archiving or distribution.
Build Discord bot audio from MKV content
Discord uses Opus for all voice audio. Extract audio from MKV files and convert to Opus to use in Discord bots. Libraries like discord.js and discord.py support Opus natively for low-latency voice channel playback.
Optimize MKV audio for low-bandwidth streaming
Opus delivers significantly better audio than AAC or MP3 at bitrates below 64 kbps. Extract MKV audio to Opus for streaming applications that must work over slow or metered mobile connections.
Extract anime or film audio for WebRTC applications
WebRTC uses Opus for real-time audio transmission. Converting MKV audio to Opus lets you integrate pre-recorded film or animation audio into browser-based WebRTC streaming tools without codec conversion overhead.
Create self-hosted podcast audio from MKV recordings
Self-hosted podcast servers like Icecast support Opus streaming. Convert MKV video recordings to Opus for compact, high-quality audio delivery to podcast listeners on bandwidth-limited connections.
How to Convert Matroska to Opus
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1
Upload your MKV file
Drag and drop your .mkv file onto the converter or click to browse and select it. Files up to 500MB are supported.
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2
Server-side Opus encoding
Your MKV is uploaded over HTTPS and FFmpeg extracts and decodes the audio stream, encoding it as Opus in an OGG container. The video stream is discarded. Processing completes in seconds.
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3
Download your Opus file
Click Download to save the .opus file. Both the original MKV and converted Opus are automatically deleted from our servers after download.
Frequently Asked Questions
MKV files can contain various codecs. Opus outperforms AC-3, MP3, and AAC at bitrates below 128 kbps, and matches or exceeds them at higher bitrates. Converting to Opus gives you a highly efficient, open-source output regardless of what codec was in the source MKV.
Yes. Both DTS and Opus are lossy codecs. Converting from DTS to Opus involves decoding DTS and re-encoding to Opus, adding another generation of lossy compression. At high Opus bitrates (128+ kbps), this difference is typically inaudible.
Opus audio is stored in an OGG container with a .opus extension. Some players may list it as .ogg — both are the same format.
Yes. Discord voice channels use Opus encoding natively. Python (discord.py + PyNaCl) and Node.js (discord.js + @discordjs/opus) both accept Opus audio files for playback in voice channels.
FFmpeg encodes Opus at a high variable bitrate by default, typically 128 kbps. Opus at 128 kbps is generally considered transparent — indistinguishable from lossless for most content and listeners.
Yes. Opus supports multi-channel audio including 5.1 and 7.1 configurations. Multi-channel audio from MKV will be preserved in the Opus output.
Yes. Opus is supported natively in Chrome, Firefox, Edge, and Opera. Safari added Opus support in version 16. It is the preferred format for WebRTC audio in all major browsers.
Yes. ChangeThisFile is completely free. No signup, no limits, no fees.
Very fast. Opus encoding is computationally efficient. A one-hour MKV file typically converts to Opus in under 30 seconds on our servers.
Yes. All uploads are HTTPS-encrypted and files are deleted from our servers immediately after you download the converted Opus file. We never retain your content.
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