The Advanced Audio Coding audio format, or AAC for short, offers very good sound quality even at low bit rates. While you need a bit rate of at least 192 kbit / s for CD quality with MP3, you can achieve the same quality with AAC from a bit rate of at least 128 kbit / s. As a result, AAC files are much smaller than MP3 files and are often used, for example, when streaming music or Internet radio.
AAC became known especially through iTunes. The music player developed by Apple preferably uses this format. One reason for this is that copy protection can be built into AAC, preventing uncontrolled transfer of music files.
Better than MP3
As with MP3, the AAC format removes sounds that are not perceptible to humans and therefore unnecessary. This applies both to inaudible frequency ranges and to redundant tones that arise, for example, by overlapping. Therefore, a low data rate does not necessarily mean a deterioration of the sound. A decisive advantage over MP3: AAC files have the same quality and a significantly smaller file size than MP3 files.
AAC has other advantages as well. AAC supports up to 48 channels, while MP3 only supports six. Also, the scanning range is significantly wider with AAC. It ranges from 8 to 96 kHz. AAC achieves good sound quality starting at 94 kbit / s. Bit rates of 192 kbit / s or 224 kbit / s correspond to almost lossless CD quality. By the way, AAC files mainly use the .mp4 file extension and are used by Apple iTunes, Quicktime, mobile phones, car radios, Nintendo and Playstation, among others. AAC is also used for Internet radio.
Compress AAC
If you want to compress a file according to AAC, you can use various software programs, so-called encoders, for this. Both free and paid software are available on the market, and there are few programs that work really well. Some examples are Nero or Liquifier.
Where does the AAC come from?
AAC was developed at the Fraunhofer Institute, with other companies such as Sony and Nokia also involved. The goal was to develop a standardized audio format that offered very good sound quality in the smallest possible size. AAC is a further development of the MPEG-2 standard. Later more AAC profiles were developed under MPEG4. If you want to use AAC commercially, you have to pay for a license, which is why most encoders are paid.
AAC comes with different profiles
AAC has different profiles that can be selected for compression. Typically the LC profile is used, which is suitable for medium to high data rates. Other profiles are the HE profile, the SSR profile and the LD profile. Due to the different profiles, in some players it may happen that data such as the artist or the title is not displayed correctly because the existing profile is not supported correctly.
