A codec (coder-decoder) is software that compresses or decompresses media. While MX Player includes basic codecs, legal restrictions (patents on Dolby and DTS) prevent the app from shipping with AC3 or DTS support. is a user-installed library (a .so or .zip file) that adds this missing support.

With the correct ARMv8 NEON codec installed, MX Player 1.13.0 gains support for:

: Place the downloaded .zip file in your device’s internal storage. Upon opening MX Player, it should automatically detect the file and prompt you to install it.