FormatDrop
Audio Format

AMR

Adaptive Multi-Rate Audio

AMR (Adaptive Multi-Rate) is the standard audio codec used for voice calls and voice recordings on mobile phones. It's optimised entirely for human speech — delivering intelligible voice quality at very low bitrates (4.75–12.2 kbps), making it ideal for GSM calls, voicemail, and voice memos on older smartphones. Android devices (especially older Samsung, HTC, and LG phones) often save voice recordings as AMR files. If you've received a voice message you can't play, it's probably AMR.

What is AMR?

AMR uses multi-rate narrow-band speech encoding — it adapts its bitrate based on available bandwidth, from 4.75 kbps to 12.2 kbps in narrow-band mode (AMR-NB, 8 kHz sample rate) or 6.6–23.85 kbps in wide-band mode (AMR-WB, 16 kHz — also known as G.722.2). AMR-NB is optimised for GSM/EDGE voice calls; AMR-WB (HD Voice) provides significantly better voice quality on 3G/4G networks. The codec uses dynamic bitrate adaptation — it can lower bitrate during silence and increase it for complex speech. AMR files use the .amr extension (narrow-band) or .3gp/.3g2 container (for mobile video with AMR audio tracks).

AMR pros and cons

Advantages

  • Extremely small file sizes — a 1-minute voice memo is approximately 60–100 KB
  • Optimised for speech — intelligible voice at very low bitrates
  • Standard for mobile voice recording on Android devices
  • Supported by 3GPP standard — every mobile carrier and device
  • AMR-WB (HD Voice) provides excellent speech quality for modern calls
  • VLC and FFmpeg play AMR natively

Limitations

  • Not suitable for music — narrow-band focus makes it sound terrible for non-speech
  • Low audio quality (8 kHz sample rate for AMR-NB) — sounds 'telephone-like'
  • Limited software support outside VLC and FFmpeg
  • Not supported by macOS QuickTime or Windows Media Player natively
  • Rarely produced by modern smartphones (replaced by AAC or Opus)
  • No stereo support

When should you convert AMR files?

Convert AMR to MP3 or AAC for sharing voice memos with people who may not be able to play AMR: `ffmpeg -i input.amr -c:a libmp3lame -q:a 4 output.mp3`. Convert AMR to WAV for editing in audio software: `ffmpeg -i input.amr output.wav`. Note: converting AMR to MP3 or WAV creates a larger file with the same narrow-band voice quality — it doesn't improve the audio. Convert AMR to OGG Opus for the best quality-per-size ratio for voice: `ffmpeg -i input.amr -c:a libopus -b:a 32k output.ogg`.

All FormatDrop conversions run entirely in your browser — no file upload, no server processing. Your files stay on your device.

AMR FAQ

How do I play AMR files on iPhone or Windows?
iPhone: VLC for iOS opens AMR files. Alternatively, convert to MP3 first using an online converter or FFmpeg on a computer, then transfer to iPhone. Windows: VLC plays AMR natively. Windows Media Player does not support AMR without additional codec packs. The quickest solution on any platform is to open AMR in VLC.
Why do Android voice recordings save as AMR?
Older Android devices (pre-2015) defaulted to AMR for voice recordings because it's the smallest possible file size for voice — essential when storage was limited. Modern Android devices use AAC or Opus for voice recording, which provides better quality. If you're still getting AMR recordings, check your voice recorder app's settings and change the output format to AAC or MP3.
Can I convert AMR to MP3?
Yes: `ffmpeg -i input.amr -c:a libmp3lame -q:a 4 output.mp3`. Online converters like CloudConvert also handle AMR to MP3. The resulting MP3 will have the same narrow-band (telephone) audio quality as the AMR — conversion doesn't improve quality, it just changes the format to one that plays in more apps.
What is AMR-WB vs AMR-NB?
AMR-NB (Narrow-Band) uses an 8 kHz sample rate — suitable for basic voice intelligibility, sounds like a telephone call. AMR-WB (Wide-Band, also called HD Voice or G.722.2) uses a 16 kHz sample rate — significantly better voice quality, closer to natural speech. Modern 4G/VoLTE calls use AMR-WB. VoIP applications like WhatsApp and Signal use Opus codec, which is superior to both.

More formats

HEICWebPAVIFEPUBWebMOpusMP3WAVM4AFLACAACMP4AVIMKVMOVJPGPNGGIFSVGTIFFICOBMPEPSARWOGGWMVPPTXPagesPDFDOCXRAWHEVCH.264AIFFM4VWMA3GPDNGRTFPSDOGVTSFLVAIXLSXCSVZIPAPNGMIDIJPEG XLMPG/MPEGVOBM2TSAC3ALACDTSJP2HEIFAPECBZ3G2SRTDOCPPTXLSODTODSM3URAR7ZM4BTXTMOBITARGZJSONXMLYAMLKEYMTSCR2NEFMXFTGACAFASSVTTDSFRMF4VWVASFRMVBORFRW2EAC-3TTA