MKA vs OPUS
A detailed comparison of Matroska Audio and Opus Audio — file size, quality, compatibility, and which format to choose for your workflow.
Matroska Audio
Audio FilesMKA is the audio-only Matroska container supporting any audio codec.
About MKA filesOpus Audio
Audio FilesOpus 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.
About OPUS filesStrengths Comparison
MKA Strengths
- Holds any audio codec — universal container.
- Multiple audio tracks in one file.
- Chapter markers, attachments, metadata.
- Open standard, patent-free.
OPUS 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
MKA Limitations
- Limited hardware support — most audio players don't recognize MKA.
- Streaming services never adopted it.
- Overshadowed by FLAC for lossless and AAC for lossy.
- Tooling less mature than MKV.
OPUS 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.
Technical Specifications
| Specification | MKA | OPUS |
|---|---|---|
| MIME type | audio/x-matroska | audio/opus |
| Extension | .mka | — |
| Container | Matroska (EBML) | — |
| Codecs | Any audio codec — FLAC, Opus, Vorbis, AAC, MP3, DTS, TrueHD | — |
| Siblings | .mkv (video), .mks (subtitles), .webm (restricted web subset) | — |
| Extensions | — | .opus, .ogg (container) |
| Standard | — | RFC 6716 (2012) |
| Sample rates | — | 8, 12, 16, 24, 48 kHz |
| Latency | — | 5-60 ms (configurable) |
Typical File Sizes
MKA
- Single-track FLAC 20-30 MB
- Full album FLAC (10 tracks + chapters) 250-400 MB
- Multi-language audiobook 500 MB - 2 GB
OPUS
- 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
Ready to convert?
Convert between MKA and OPUS online, free, and without installing anything. Encrypted upload, automatic deletion after 2 hours.
Frequently Asked Questions
MKA (Matroska 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.
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 MKA 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.
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 MKA 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.
MKA 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.