Convert Windows Media Video (.wmv) to Adaptive Multi-Rate Audio (.amr) online for free. Fast, secure video conversion with no watermarks or registration.
Conversion settings — add a file to adjust
Upload your .wmv 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.
WMV files carry WMA audio in Microsoft's ASF container, while AMR (Adaptive Multi-Rate) is a narrowband speech codec developed by ETSI for GSM cellular networks. AMR operates at 8 kHz with bitrates from 4.75 to 12.2 kbps, using algebraic CELP encoding optimized exclusively for human voice. Converting WMV to AMR extracts the audio, downsamples to 8 kHz mono, and encodes it for the most extreme voice compression available — producing files under 6 MB per hour of speech.
AMR's sole purpose is ultra-compact voice encoding for mobile telephony. If you have WMV recordings of meetings, depositions, interviews, or phone calls and need the absolute smallest possible audio files for MMS delivery, legacy mobile voice memo systems, or VoIP archival, AMR achieves compression ratios that no other format can match for speech content.
FFmpeg decodes the WMA audio from the ASF container, downsamples to 8 kHz mono (AMR-NB requirement), and encodes using libopencore_amrnb at the selected bitrate (4.75–12.2 kbps). AMR uses 20ms CELP frames with built-in voice activity detection (VAD) and comfort noise generation (CNG). The output is a raw AMR file or AMR wrapped in a 3GP container for mobile compatibility.
At 12.2 kbps, AMR sounds like a clear phone call — perfectly adequate for speech comprehension. Below 7.4 kbps, speech remains intelligible but sounds compressed with noticeable artifacts. Music and non-speech audio are severely distorted at any AMR bitrate — the codec is not designed for them.
| Device | WMV | AMR |
|---|---|---|
| Windows PC | Native | Partial |
| macOS | Partial | Partial |
| iPhone/iPad | Partial | Partial |
| Android | Partial | Partial |
| Linux | Partial | Partial |
| Web Browser | No |
Resolution: 1920x1080
Bitrate: 8-12 Mbps
H.264 recommended for fast processing
Resolution: 1080x1080
Bitrate: 3.5 Mbps
Square or 9:16 for Reels
Resolution: 1080x1920
Bitrate: 4 Mbps
9:16 vertical, under 60s ideal
Resolution: 1280x720
Bitrate: 5 Mbps
Under 140s, 512MB max
Resolution: 960x540
Bitrate: 2 Mbps
16MB limit for standard, 64MB for document
Resolution: 1280x720
Bitrate: 4 Mbps
WMV to AMR conversion extracts voice audio into the most space-efficient speech format available. It is specialized for telephony-grade voice delivery, not general audio.
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| Caracteristică | WMV | AMR |
|---|---|---|
| Nume complet | Windows Media Video | Adaptive Multi-Rate Audio |
| Extensie | .wmv | .amr |
| Cel mai potrivit pentru | Windows native | Speech optimized |