Quick Verdict
Use AMR when…
Use AMR only when storage and bandwidth are extremely constrained and content is voice — voicemail systems, ham radio recordings, network-limited voice apps.
Use MP3 when…
Use MP3 for general audio — voice notes, music, podcasts, any content where you want broad compatibility with phones, computers, and web platforms.
AMR vs MP3: Feature Comparison
| Feature | AMR | MP3 |
|---|---|---|
| Optimization | Voice (300 Hz – 3.4 kHz) | Full audio range |
| Typical bitrate | 12.2 kbps | 128–320 kbps |
| File size (1 minute voice) | ~90 KB | ~960 KB at 128 kbps |
| Music quality | Unusable | Excellent at 256+ kbps |
| Web/browser support | None | Universal |
| Mobile compatibility | Older phones, voicemail | Every phone |
When AMR wins
- ✓Optimization: Voice (300 Hz – 3.4 kHz)
- ✓Typical bitrate: 12.2 kbps
- ✓File size (1 minute voice): ~90 KB
When MP3 wins
- ✓Optimization: Full audio range
- ✓Typical bitrate: 128–320 kbps
- ✓File size (1 minute voice): ~960 KB at 128 kbps
Frequently asked questions
Will MP3 sound better than AMR for voice?
Yes — even MP3 at 64 kbps sounds significantly better than AMR at 12.2 kbps for voice. The bitrate gap is huge. For best voice quality, use MP3 at 96 kbps mono or AAC at 64 kbps mono.
How do I convert AMR to MP3?
FFmpeg: `ffmpeg -i input.amr -c:a libmp3lame -b:a 128k output.mp3`. For voice content, mono is sufficient: `-ac 1 -b:a 64k`.
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