MKA is Matroska file format's audio version, which got its name from the Russian word matryoshka (which reffers to the famous nesting dolls).
MKA is not a popular audio format, therefore users might want to encode their files to more common multimedia formats.
MKA encoders will allow their users to customize various value of their MKA source file such as the sample rate or bit rate.
MKA converters will also enable their users to select the output folder and the destination format, according to one's specific needs.