amr

.amr — Adaptive Multi-Rate

3GPP (3rd Generation Partnership Project) · 1999

Developer

3GPP (3rd Generation Partnership Project)

What is a .amr file?

The Adaptive Multi-Rate (AMR) audio codec is a speech-oriented audio data compression format. It is widely used in mobile phones for voice calls due to its ability to adapt its bit rate to the network conditions. This results in a good balance between audio quality and bandwidth efficiency.

Programs That Open .amr Files

Platform	Program
Windows	VLC Media Player	Free
	Foobar2000	Free
	Windows Media Player	Free	Official
macOS	VLC Media Player	Free
	QuickTime Player	Free	Official
	MPlayerX	Free

Common Problems with .amr Files

⚠️ File won't play on a specific device or software.

Ensure the device or software supports the AMR codec. You may need to convert the file to a more widely supported format like MP3 or AAC using a converter tool.

⚠️ Poor audio quality.

This can sometimes happen if the AMR file was encoded with a very low bitrate. Converting to a higher bitrate format or re-encoding the AMR file with a better bitrate may help.

⚠️ File corruption.

If the AMR file is corrupted, it might be unplayable. Try re-downloading or obtaining the file again from the source. If possible, attempt repair with specialized audio recovery software.

Frequently Asked Questions

What is an AMR file?▼

An AMR file is an audio file that uses the Adaptive Multi-Rate codec, primarily designed for speech compression and widely used in mobile communications.

Can I convert AMR files to MP3?▼

Yes, you can convert AMR files to MP3 or other audio formats using various online converters or desktop software like VLC Media Player or dedicated audio converters.

Why does my AMR file sound bad?▼

The audio quality of an AMR file depends on the bitrate it was encoded with. Low bitrates, common in mobile calls, can result in lower fidelity. Converting to a higher bitrate format or re-encoding might improve quality if the original encoding allowed for it.

Technical Details

AMR files typically contain audio data encoded using the AMR narrowband or wideband speech codecs. The header signature is often absent, but files might begin with the Magic number '0x23' followed by '0x41' ('#A' in ASCII) for the AMR-WB format.

Did You Know?

AMR was developed by a partnership of Ericsson, Nokia, and VoiceAge.

It is an open standard defined by the 3GPP.

AMR-NB (Narrowband) is commonly used for voice calls, while AMR-WB (Wideband) offers higher fidelity.

Security Information

AMR files themselves are audio data and do not inherently contain malicious code. However, like any file, they can be a vector for malware if they are part of a malicious download or attached to a phishing email. Always ensure you are downloading AMR files from trusted sources.