Convert WMA to AMR — Free Online Converter
Convert Windows Media Audio (.wma) to Adaptive Multi-Rate Audio (.amr) online for free. Fast, secure audio conversion with no watermarks or registrati...
2M+ filer konvertert
Klarert av tusenvis av brukere
Sikker overføring
HTTPS-krypterte opplastinger
Personvern først
Filer slettes automatisk etter behandling
Ingen registrering
Begynn å konvertere med en gang
Fungerer overalt
Alle nettlesere, alle enheter
Slik konverterer du
Upload your .wma file by dragging it into the upload area or clicking to browse.
Choose your output settings. The default settings work great for most files.
Click Convert and download your .amr file when it's ready.
About WMA to AMR Conversion
WMA is Microsoft's audio codec delivering compressed audio typically at 64-320 kbps. AMR (Adaptive Multi-Rate) is a speech-optimized codec created by ETSI for GSM and UMTS mobile voice calls. AMR-NB operates at 8 kHz with bitrates from 4.75 to 12.2 kbps, while AMR-WB extends to 16 kHz at up to 23.85 kbps.
Converting WMA to AMR re-encodes the audio through a speech-optimized codec, dramatically reducing file size while maintaining intelligible voice reproduction. This conversion is specifically designed for speech content — AMR handles music poorly but excels at clear voice at minimal bitrates.
Why Convert WMA to AMR?
AMR is the native codec for billions of mobile phones and the backbone of GSM voice infrastructure. Telecom voicemail systems, IVR platforms, and MMS gateways often require AMR input. If you have WMA voice recordings from a Windows-based system that need to enter the mobile telephony pipeline, AMR conversion is required.
The extreme compression (128 kbps WMA to 12.2 kbps AMR-NB) makes AMR ideal for mass archival of voice content. Call center recordings, dictation files, and interview archives stored as WMA can be compressed further for long-term storage.
Common Use Cases
- Converting WMA voicemail recordings for mobile telephony systems
- Preparing WMA voice memos for MMS delivery to feature phones
- Compressing WMA call recordings for long-term archival at minimal storage cost
- Delivering WMA audio to IVR systems that require AMR input format
- Migrating Windows-recorded voice content to mobile-compatible AMR format
How It Works
FFmpeg decodes the WMA stream to PCM, resamples to 8 kHz (AMR-NB) or 16 kHz (AMR-WB), downmixes to mono, and encodes using libopencore-amrnb or libopencore-amrwb. The AMR codec uses ACELP (Algebraic Code-Excited Linear Prediction) optimized for the human speech spectrum. Since both WMA and AMR are lossy, the transcode compounds quality loss. The output is written as raw AMR (.amr) or wrapped in a 3GP container.
Quality & Performance
Double lossy transcoding (WMA to AMR) produces lower quality than converting from an uncompressed source. AMR-NB is narrowband (300-3400 Hz) and sounds like a standard phone call. AMR-WB extends to 50-7000 Hz for HD Voice quality. Neither is suitable for music. For the best results, start from WMA Lossless or the highest available WMA bitrate.
Device Compatibility
| Device | WMA | AMR |
|---|---|---|
| Windows PC | Native | Partial |
| macOS | Partial | Partial |
| iPhone/iPad | Partial | Partial |
| Android | Partial | Partial |
| Linux | Partial | Partial |
| Web Browser | No | No |
Recommended Settings by Platform
Spotify
Resolution: N/A
Bitrate: 320 kbps
OGG Vorbis preferred
Apple Music
Resolution: N/A
Bitrate: 256 kbps
AAC format required
SoundCloud
Resolution: N/A
Bitrate: 128 kbps
Lossless FLAC/WAV for best quality
Podcast
Resolution: N/A
Bitrate: 128 kbps
MP3 mono for spoken word
Tips for Best Results
- 1Use AMR-WB at 23.85 kbps for the best voice quality when the target system supports wideband
- 2Pre-process the WMA with noise reduction before conversion — AMR handles clean speech much better than noisy recordings
- 3Only convert speech content to AMR — music will be severely degraded by the speech-optimized codec
- 4Wrap the AMR output in a 3GP container for broader mobile device compatibility
- 5For higher-quality voice archival, consider Opus at 16-32 kbps instead of AMR — Opus handles speech better at similar bitrates
Related Conversions
WMA to AMR conversion bridges Windows audio with mobile telephony infrastructure. Use AMR-WB for HD Voice quality and reserve AMR-NB for legacy systems requiring narrowband compatibility.