MKA is an audio container format. It supports some types of audio compression algorithms. The .mka file extension belongs to the Matroska format (Matröška, Matryoshka). Thus, it serves to specifically designate the file type "Matroska Audio File" (Matroska Audio File). Matroska is an open cross-platform standard. It is a modern extensible multimedia container format. It is error resistant. It is suitable for streaming HTTP / RTP. Supports multiple subtitle tracks, audio, video. The Matroska standard is supported in the native mode by many software players and hardware devices, including, for example, receivers, televisions, smartphones, etc. A .mka file is a regular Matroska container that has one or more audio tracks. They are encoded by any of the supported codecs. In most cases, AAC and AC3 (Dolby Digital) codecs are used. Playing a .mka file needs the support of the standard Matroska container format. But not only. There must also be a specific audio codec with which the tracks are encoded. Often, MKA files are used as external audio tracks for movies in other languages. Or with other content, or with sound quality. Say multi-channel sound, director’s comments. .Mka audio files are used as containers for high-quality multi-channel music.
AU is an audio file format created in Audacity. This is a free cross-platform program designed to edit audio files. AU format (Audio Units) was developed by Sun Microsystems. This format greatly simplifies the task of reliable storage of audio files. An AU file consists of 3 parts: a header (max. 24 bytes), a description block of various sizes, and audio data. The file format is used on computers running the Sun or Unix operating system. However, it opens with other audio players. The AU format uses the logarithmic encoding method, previously very popular on computers running the Sun SPARCstation operating system. Previous sound file formats, in order to reduce the size, used the logarithmic scale of recording samples. Among the representatives of such formats, the Sun AU group of formats, which are still in action, gained great fame. Problems with opening the AU file usually manifest themselves when there are no corresponding applications that would be installed on the PC. Applications that use .AU files are Apple QuickTime Player, Microsoft Windows Media Player, Real Player, Winamp, and other widely used audio players. And this is the vast majority of professional audio editors.