3GA is a 3GPP audio file created in 1998. It was created by the 3rd Generation Partnership Project. It is used mainly on mobile devices in order to record, play and transmit audio data. 3GPP (3rd Generation Partnership Project) is a consortium that develops specifications for mobile telephony. The format resembles 3GP files, however, it includes only audio data. In most cases, 3GA files are used by mobile phones in order to record and transmit audio data. For example, this is how audio is recorded in Samsung Galaxy phones. The .3GA file extension can be changed to .3GP, which is widespread. Everything is supported by many programs. The 3GA format uses an adaptive coding audio codec with variable speed (AMR, AMR-NB, GSM-AMR). The development of this codec was done in order to compress encoded speech signals using adaptive modulation. In 1999, the 3GPP consortium adopted the Adaptive Variable Rate Coding (AMR) standard. Currently, it is used by GSM and UMTS communication systems. It is this format for speech recording that has found wide application on mobile devices. We note at the same time that it is not possible to play such files very often on certain devices.
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.