Convert MKA to AMR

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MKA vs AMR Format Comparison

Aspect MKA (Source Format) AMR (Target Format)
Format Overview
MKA
Matroska Audio Container

Matroska Audio (MKA) is the audio-only variant of the Matroska multimedia container format (.mkv), developed by the Matroska open-source project since 2002. MKA can encapsulate virtually any audio codec — including FLAC, AAC, Opus, Vorbis, DTS, and AC3 — within a single flexible container. It excels at storing multi-track audio, chapter markers, and rich metadata, making it popular for concerts, audiobooks, and archival collections.

Lossless Modern
AMR
Adaptive Multi-Rate Audio

Adaptive Multi-Rate (AMR) is a speech-optimized lossy audio codec standardized by 3GPP for mobile telephony. Operating at low bitrates from 4.75 to 12.2 kbps, AMR dynamically adjusts its bitrate based on network conditions. While highly efficient for voice, AMR is unsuitable for music due to its narrow-band focus and aggressive compression targeting the human speech frequency range.

Lossy Legacy
Technical Specifications
Sample Rates: Any (codec-dependent)
Bit Depth: Any (codec-dependent)
Channels: Mono to 7.1+ surround (codec-dependent)
Codecs: FLAC, AAC, Opus, Vorbis, AC3, DTS, PCM, MP3, etc.
Container: Matroska/EBML (.mka)
Sample Rates: 8 kHz (AMR-NB), 16 kHz (AMR-WB)
Bit Rates: 4.75–12.2 kbps (NB), 6.6–23.85 kbps (WB)
Channels: Mono only
Codec: AMR-NB, AMR-WB (G.722.2)
Container: 3GP (.3gp), AMR (.amr)
Audio Encoding

MKA wraps audio streams in the Matroska EBML container without re-encoding, preserving the original codec data bit-for-bit:

# Mux FLAC audio into MKA container
ffmpeg -i input.flac -codec:a copy output.mka

# Mux multiple audio tracks into MKA
ffmpeg -i track1.flac -i track2.aac \
  -map 0:a -map 1:a -codec:a copy output.mka

AMR uses algebraic code-excited linear prediction (ACELP) optimized for speech compression:

# Encode to AMR-NB at 12.2 kbps
ffmpeg -i input.wav -codec:a libopencore_amrnb \
  -b:a 12.2k -ar 8000 -ac 1 output.amr

# Encode to AMR-WB at 23.85 kbps
ffmpeg -i input.wav -codec:a libvo_amrwbenc \
  -b:a 23.85k -ar 16000 -ac 1 output.amr
Audio Features
  • Metadata: Matroska tags (title, artist, album, arbitrary key-value pairs)
  • Album Art: Embedded attachments (cover images, fonts, any file)
  • Gapless Playback: Supported via codec delay and trimming
  • Streaming: Supported via WebM subset and HTTP streaming
  • Surround: Full multichannel support (codec-dependent)
  • Chapters: Native chapter support with nested chapters and names
  • Metadata: Minimal metadata support
  • Album Art: Not supported
  • Gapless Playback: Not applicable
  • Streaming: Designed for real-time telephony streaming
  • Surround: Not supported (mono only)
  • Chapters: Not supported
Advantages
  • Supports virtually any audio codec without re-encoding
  • Multiple audio tracks in a single file (multi-language, commentary)
  • Native chapter markers for audiobooks and concert recordings
  • Rich metadata and attachment support (cover art, lyrics)
  • Open-source format with no licensing fees
  • Lossless container — no quality loss from the container itself
  • Extremely small file sizes (ideal for voice recordings)
  • Dynamic bitrate adaptation for varying network conditions
  • Standard format for 3G/4G mobile voice calls
  • Very low CPU requirements for encoding/decoding
  • Excellent speech intelligibility at low bitrates
  • Wide support on mobile phones
Disadvantages
  • Limited native support on Apple devices and iOS
  • Not recognized by many car audio systems and portable players
  • Some media players may not support all embedded codecs
  • Larger container overhead compared to raw audio formats
  • Less common than M4A or MP3 for single-track audio distribution
  • Very poor music quality (speech-only optimization)
  • Mono only — no stereo or multichannel support
  • Low sample rate (8 kHz NB, 16 kHz WB)
  • Limited desktop software support
  • Outdated for modern applications (VoLTE uses EVS)
Common Uses
  • Multi-track audio collections (concerts, live recordings)
  • Audiobooks with chapter navigation
  • Archival storage with lossless codecs (FLAC in MKA)
  • Multi-language audio packaging
  • Extracted audio tracks from MKV video files
  • Mobile phone voice recordings
  • 3G/4G voice call recording
  • Voice memos on older mobile devices
  • Telephony voicemail systems
  • Low-bandwidth voice communication
Best For
  • Storing multiple audio tracks in a single organized file
  • Audiobooks and podcast series with chapter markers
  • Archiving concert recordings with metadata and cover art
  • Flexible audio packaging where codec choice may vary
  • Voice recordings where file size is critical
  • Mobile telephony applications
  • Legacy voice memo playback and archiving
  • Low-bandwidth voice transmission
Version History
Introduced: 2002 (Matroska Project)
Current Version: Matroska v4 (EBML-based)
Status: Active development, IETF standardization (RFC 8794)
Evolution: v1 (2002) → v2 (2004) → v3 (2010) → v4 (2014+)
Introduced: 1999 (3GPP, ETSI)
Current Version: AMR-NB, AMR-WB (G.722.2)
Status: Legacy, being replaced by EVS
Evolution: AMR-NB (1999) → AMR-WB (2001) → AMR-WB+ (2004) → EVS (2014)
Software Support
Media Players: VLC, MPC-HC, foobar2000, mpv, PotPlayer
DAWs: Limited (extract audio first for editing)
Mobile: Android (VLC, MX Player), iOS (VLC, Infuse)
Web Browsers: Limited native support (WebM subset only)
Tools: MKVToolNix, FFmpeg, MediaInfo, HandBrake
Media Players: VLC, QuickTime, Windows Media Player
Mobile: Android (native), iOS (native playback)
Telephony: 3GPP-compliant mobile networks
Tools: FFmpeg, SoX, GoldWave
Web Browsers: Limited support

Why Convert MKA to AMR?

Converting MKA to AMR extracts audio from the Matroska Audio container and re-encodes or remuxes it into AMR format. MKA files can contain virtually any audio codec, but many devices and applications do not recognize the .mka extension. By converting to AMR, you gain broad compatibility with media players, mobile devices, and audio editing software that expect standard audio file extensions.

AMR uses adaptive multi-rate audio encoding to produce smaller files at the cost of some quality loss. When your MKA file contains high-bitrate or lossless audio that is too large for practical distribution, converting to AMR significantly reduces file size while maintaining perceptually transparent quality at appropriate bitrates.

MKA's strength lies in its container flexibility — it can hold multiple audio tracks, chapter markers, and rich metadata. However, this versatility comes at the cost of compatibility. Most car stereos, portable players, and smart speakers cannot play .mka files directly. Converting to AMR ensures your audio is accessible on the widest range of devices and platforms.

The conversion process decodes the audio stream from the MKA container and encodes it into AMR. If the source MKA contains multiple audio tracks, the primary (first) track is typically extracted for conversion. For best results, choose a bitrate and quality setting appropriate for your intended use — higher settings for archival and critical listening, lower settings for portable playback and streaming.

Key Benefits of Converting MKA to AMR:

  • Wider Compatibility: Play your audio on devices that do not support .mka files
  • Standard Format: AMR is recognized by virtually all media players and audio editors
  • Simplified Sharing: Recipients can open AMR files without installing special software
  • Mobile Playback: Most phones and tablets natively support AMR audio
  • Web Integration: Use AMR files directly in websites, apps, and online platforms
  • Editing Support: Import AMR directly into DAWs and audio editors for production work
  • Streaming Ready: AMR works with standard streaming protocols and services

Practical Examples

Example 1: Extracting Audio for Mobile Playback

Scenario: A user has concert recordings stored as MKA files with FLAC audio inside, but their smartphone cannot play .mka files and they need to transfer the music for on-the-go listening.

Source: live_concert_2024.mka (78 min, FLAC inside, 312 MB)
Conversion: MKA → AMR
Result: live_concert_2024.amr

Workflow:
1. Upload MKA file to the converter
2. Select AMR as the target format
3. Download the converted file
4. Transfer to phone or portable player
5. Enjoy playback on any compatible device

Example 2: Preparing Audio for Editing Software

Scenario: A podcast editor receives multi-track MKA files from a recording session but their DAW only accepts standard audio formats for import.

Source: podcast_session_ep15.mka (45 min, multi-track, 180 MB)
Conversion: MKA → AMR
Result: podcast_session_ep15.amr

Benefits:
✓ DAW-compatible format for immediate import
✓ No need to install Matroska plugins
✓ Standard format recognized by all editing software
✓ Clean audio extraction from container
✓ Ready for mixing, EQ, and mastering

Example 3: Converting for Web and Streaming Use

Scenario: A content creator has audiobook chapters stored as MKA files but needs to upload them to a platform that only accepts common audio formats.

Source: chapter_07_dragons.mka (32 min, Opus inside, 24 MB)
Conversion: MKA → AMR
Result: chapter_07_dragons.amr

Platform requirements met:
✓ Standard audio format accepted by hosting service
✓ Compatible with web-based audio players
✓ Proper file extension for content management
✓ Metadata preserved where format allows
✓ Ready for distribution and streaming

Frequently Asked Questions (FAQ)

Q: What audio codec is inside my MKA file?

A: MKA is a container that can hold any audio codec — FLAC, AAC, Opus, Vorbis, MP3, AC3, DTS, PCM, and more. You can check the internal codec using MediaInfo or FFmpeg. Our converter automatically detects and handles the internal codec during conversion to AMR.

Q: Will I lose quality converting MKA to AMR?

A: It depends on the codecs involved. If your MKA contains lossless audio (like FLAC) and AMR is a lossy format, some quality will be lost during encoding. If both are lossless, the conversion preserves full quality. If the source is already lossy, converting to another lossy format adds another generation of compression artifacts.

Q: Why can't I play MKA files on my device?

A: MKA uses the Matroska container format, which is not natively supported on all devices — particularly Apple products, car stereos, and basic portable players. Converting to AMR solves this by repackaging the audio in a universally recognized format.

Q: Can MKA files contain multiple audio tracks?

A: Yes — one of MKA's key features is multi-track support. A single MKA file can contain multiple audio streams (e.g., different languages or commentary tracks). When converting to AMR, typically only the primary audio track is extracted.

Q: How large will the converted AMR file be?

A: File size depends on the source codec and AMR encoding settings. Converting from lossless MKA (e.g., FLAC inside) to a lossy AMR will produce a much smaller file. Converting between lossless formats maintains similar file sizes. The converter uses optimal default settings for good quality-to-size balance.

Q: Does the converter preserve metadata from MKA?

A: The converter transfers compatible metadata (title, artist, album) to the AMR output where the target format supports it. However, MKA-specific features like chapter markers, attachments, and multi-track information may not transfer, as most standard audio formats do not support these features.

Q: What is the difference between MKA and MKV?

A: MKA (.mka) and MKV (.mkv) both use the Matroska container format. MKV is for video (with audio), while MKA is the audio-only variant — identical container structure but containing only audio streams, metadata, and optional attachments. Converting MKA to AMR extracts just the audio content.

Q: Is MKA an open-source format?

A: Yes — Matroska (including MKA) is fully open-source, developed under LGPL license. The specification has been standardized by IETF as RFC 8794. This means no licensing fees, no patents, and perpetual availability — making it excellent for long-term archival alongside its conversion to more compatible formats like AMR.