Presentation of the AAC format
AAC (Audio Advanced Coding) is an audio data compression format developed by the Fraunhofer Institute in collaboration with AT&T, Nokia, Sony and Dolby.
As with the MP3 format, it is a destruction of audio data compression, called “lossy compression” (that is, lossy compression), ie the removal of certain auditory information (for example, inaudible frequencies) to the best possible compression rate, keeping a result as close as possible to the original data.
The AAC format corresponds to the international standard “ISO / IEC 13818-7” as an extension of MPEG-2, standard of the Moving Image Expert Group (MPEG).
The AAC format was chosen by the Apple company as the primary file format on iPods or in the iTunes software.
Frequently Asked Questions: M4A – AAC Format and Features
Technical properties
AAC uses a variable bit rate encoding (Variable bit rate in English, sometimes abbreviated as VBR), that is, an encoding that allows you to adjust the number of bits used per second to encode audio data according to the complexity of current at a given moment. The algorithm used is more efficient than that of MP3, enabling smaller, higher quality files to be obtained, while requiring less resources to encode or decode.
Compared to the maximum of two channels (in stereo) supported by the MP3 format, the AAC format allows polyphonic recording of up to 48 channels. The AAC format also provides sound reproduction in the 8Hz-96.0kHz frequency band, compared to 16-48kHz for the MP3 format.
Files in AAC format, with extension .mp4 (for MPEG-4), .m4a (for MPEG-4 audio) or .m4p (for protected MPEG-4), are generally smaller than files in MP3 format.
AAC Compatibility
The AAC format is not compatible with the MP3 format, this means that you must use a player that is compatible with the format or install a specific codec so that existing players can read files in AAC format.
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However, more and more software players allow you to read files in this format, and the latest hardware MP3 players support this format.
