libmpcdec-dev binary package in Ubuntu Focal arm64

 Musepack is an audio compression format with a strong emphasis on
 high quality. It's not lossless, but it is designed for transparency,
 so that you won't be able to hear differences between the original
 wave file and the much smaller MPC file.
 .
 It is based on the MPEG-1 Layer-2 / MP2 algorithms, but since 1997
 it has rapidly developed and vastly improved and is now at an advanced
 stage in which it contains heavily optimized and patentless code.
 .
 This package contains the header files, static libraries
 and symbolic links that developers using libreplaygain will need.

Source package