AAC is a sound encoded file format developed by Fraunhofer IIS, AT&T, Dolby and Sony. Its name stands for Advanced Audio Coding. The AAC format is an industry standard and was created as an improved alternative to the most common MP3 audio file format. AAC files do have slightly improved features compared to MP3s. Let's say this format provides the opportunity for improved processing of frequencies above 16 kHz. At the same time, the sound quality of AAC files is closer to the original sound source.
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.