Convert WebM Video (.webm) 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 .webm 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.
WebM files contain audio encoded with Opus or Vorbis — codecs capable of excellent broadband audio quality. AMR (Adaptive Multi-Rate) is a narrowband speech codec operating at 4.75-12.2 kbps, mono, 8 kHz — designed for GSM cellular voice calls. The quality gap between Opus and AMR is enormous.
AMR produces the smallest possible audio files — about 90 KB per minute. This extreme compression is useful only for speech content when audio must be delivered via MMS, legacy voicemail systems, or IVR telephony platforms with strict AMR format requirements.
The conversion extracts and radically compresses audio from web video sources for telephony applications.
FFmpeg extracts and decodes Opus/Vorbis from the WebM container, downmixes to mono, resamples from 48 kHz (Opus) or 44.1 kHz (Vorbis) to 8 kHz, and encodes to AMR-NB using libopencore-amrnb. The output uses the standard AMR file format with the #!AMR\n header. Opus's excellent quality is dramatically reduced to telephone bandwidth.
Quality is reduced to telephone grade. The 8 kHz sample rate limits frequency response to 300-3400 Hz. Opus/Vorbis broadband audio quality is completely destroyed — only speech intelligibility is preserved. Music and ambient sounds become unrecognizable.
| Device | WebM | AMR |
|---|---|---|
| Windows PC | Partial | Partial |
| macOS | Partial | Partial |
| iPhone/iPad | Partial | Partial |
| Android | Native | Partial |
| Linux | Partial | Partial |
| Web Browser | Native |
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
WebM to AMR is an extreme compression conversion for telephony applications, extracting speech-only audio from web sources at minimum possible file size.
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| No |
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| Funktion | WebM | AMR |
|---|---|---|
| Fullstandigt namn | WebM Video | Adaptive Multi-Rate Audio |
| Filandelse | .webm | .amr |
| Bast for | Web optimized | Speech optimized |