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.
CAF is a highly specialized audio file format. It was developed by Apple Computer, its name is an abbreviation for Core Audio File. It is a container format for audio files. CAF is distinguished by its large size from many other similar audio file formats. At the same time, the compression ratio is, on the contrary, much less than that of files of a different format, which allows compression without loss of quality compared to the original. The disadvantages of the CAF format are that not all popular players support it, and therefore such files need to be converted.