File Extension: AMR

File Type: Adaptive Multi-Rate (AMR) compressed audio

AMR is an audio data compression scheme especially suited for speech coding. It has found large use in GSM (and derivative, like UMTS) mobile phone systems. It's also the standard speech codec choosed by 3GPP.

Sample hexdump

Here's a sample hexdump of an .AMR file's header (first 256 bytes):
sample AMR audio file
Marked in yellow are the patterns used by TrID to identify an AMR file.
Check the MiniDumper tool to obtain an hexdump from a file in an easy way!

Additional informations / Related links

  • Wikipedia - Adaptive multi-rate compression
  • Library of Congress - AMR, Adaptive Multi-Rate Speech Codec
  • File Extension Seeker - AMR search results
  • FILExt - AMR extension details