amr The .amr filename extension refers to the adaptive multi-rate audio codec initially released in 1999. The format is typically used to encode speech audio and is optimized for this purpose. It can encode speech into one of two file version, either AMR-NB (narrow Band) or AMR-WB (Wide Band) which supports a broader frequency. Because of its optimization for speech audio, the format has been widely adopted as the standard speech codec for GSM and UMTS mobile phone networks by the 3rd Generation Partnership Project ' a collaborative group of organizations in the telecommunications industry.
mp3 First released in 1995 and developed by the Fraunhofer Society, the mp3 audio format is arguably one of the most recognizable audio file format that ever existed. This digital audio encoding format hails from the lossy data compression algorithm family. The format enjoys widespread support and compatibility with most handheld music players, smartphones, computers, and in car stereos most of which have native support for the format. It is also a popular format used for distribution of audio files over computer networks such as the internet. Free mp3 encoders such as LAME and audacity give authors the tools necessary to create .mp3 files.