Adaptive Multi-Rate Audio

Writable

audio · also known as AMR-NB, GSM-AMR

The Adaptive Multi-Rate (AMR or AMR-NB or GSM-AMR) audio codec is an audio compression format optimized for speech coding. AMR speech codec consists of a multi-rate narrowband speech codec that encodes narrowband (200–3400 Hz) signals at variable bit rates ranging from 4.75 to 12.2 kbit/s with toll quality speech starting at 7.4 kbit/s.

Identify it

Extensions	`.amr.3ga`
MIME types	`audio/amr`
Signatures	`2321414d52` at byte 0 (File Formats Wiki) `2321414d520a` at byte 0 (Adaptive Multi-Rate Audio)
PRONOM	`fmt/356`
Wikidata	`Q4676210`
Library of Congress	`fdd000254`

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Open it

FFmpegOpen sourcereads and writes · LGPL-2.1-or-later / GPL-2.0-or-later
ParoleOpen sourcereads · GNU General Public License
PhotoRecOpen sourcereads · GNU General Public License
Q191782Open sourcereads · GNU General Public License, version 3.0
VLC media playerOpen sourcereads · GNU Lesser General Public License, version 2.1 or later
Awave Studioreads and writes
EZ CD Audio Converterreads
Media Player (Windows 11)reads
Photorecoveryreads
Pinnacle Studio 17 Ultimatereads
Q1243769reads
QuickTime Xreads

Convert it

To	With	Fidelity	Command and losses
FLAC (Free Lossless Audio Codec) 1.2.1	FFmpeg	Lossless	`ffmpeg -i in.amr out.flac` Lossless for decoded audio; a lossy source stays as degraded as it was. WAV may reduce bit depth or drop metadata.
Waveform Audio	FFmpeg	Lossless	`ffmpeg -i in.amr out.wav` Lossless for decoded audio; a lossy source stays as degraded as it was. WAV may reduce bit depth or drop metadata.
Matroska 1-4	FFmpeg	Lossy	`ffmpeg -i in.amr out.mkv` Re-encoded with lossy codecs by default; try `-c copy` to remux without re-encoding when the codecs fit the container.
MPEG 1/2 Audio Layer 3	FFmpeg	Lossy	`ffmpeg -i in.amr out.mp3` Lossy re-encoding.
MPEG-4 Part 14	FFmpeg	Lossy	`ffmpeg -i in.amr out.mp4` Re-encoded with lossy codecs by default; try `-c copy` to remux without re-encoding when the codecs fit the container.
Ogg	FFmpeg	Lossy	`ffmpeg -i in.amr out.ogg` Lossy re-encoding.
WebM	FFmpeg	Lossy	`ffmpeg -i in.amr out.webm` Re-encoded with lossy codecs by default; try `-c copy` to remux without re-encoding when the codecs fit the container.

Sources

From Converters (FFmpeg, ImageMagick, Pandoc, LibreOffice), Just Solve the File Format Problem (File Formats Wiki), PRONOM, Wikidata. Updated 2026-10-24.

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