This format was created for online broadcasting. Opus is an audio codec for compression used on the Internet in real-time mode. Employed by programs such as Skype and Mozilla. Mostly used in interactive applications. The advantages of Opus are high audio quality and good compression. It works only on devices powered by Windows. Opus files can be converted to similar extensions.

amr

AMR (Adaptive Multi Rate): adaptive encoding with variable bitrate

This information compression format allows for optimizing speech encoding. Files in the Adaptive Multi Rate format can be created using phones and smartphones. AMR files are mostly used for voice recordings. The main advantages of the format are the large number of encoding and decoding rates, as well as the small size of the resulting content. With the help of appropriate software, an Adaptive Multi Rate file can be converted into any other audio format.