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.
AC3 is a sound file format. Its name is the abbreviation for Audio Codec 3. The format was developed by Dolby Laboratories, Inc as a modern and efficient sound compression technology. AC3 files feature Dolby Digital multi-channel surround sound. In this regard, they are widely distributed as a format for DVDs, movie theaters and game consoles. However, you can evaluate all the advantages of such files only if you have the appropriate acoustics for surround sound. An audio file of the specified format can include up to six sound channels, which creates a presence effect for the listener.