What is AAC? What is AAC format

AAC (Advanced Audio Coding), Chinese called "Advanced Audio Coding", appeared in 1997, based on MPEG-2 audio coding technology. Developed by companies such as Fraunhofer IIS, Dolby Laboratories, AT&T, and Sony to replace the MP3 format. In 2000, after the emergence of the MPEG-4 standard, AAC re-integrated its features, adding SBR technology and PS technology, in order to distinguish it from the traditional MPEG-2 AAC, also known as MPEG-4 AAC.

Advanced Audio Coding. A file compression format designed for sound data. Unlike Mp3, it uses a new algorithm for encoding, which is more efficient and has a higher price/performance ratio. With the AAC format, people can feel that the sound quality is not significantly reduced

, which is more compact. AAC format can be converted with Apple iTunes or TTP (six components)

Apple ipod, Nokia phones and Sony Walkman also support AAC format audio files.

Advantages: Compared to mp3 and other lossy formats, the AAC format has better sound quality and smaller files.

Insufficient: AAC is a lossy compression format. Compared with the popular APE, FLAC and other lossless formats, the sound quality is “nearly”. In addition, the current transmission speed of USB3.0 and 16G or more large-capacity MP3 is accelerating, and the AAC's "small" aura is no longer there.

Prospects: From a development perspective, just as “HD” is being accepted by more and more people, “lossless” must be the absolute mainstream of future music formats. The prospect of AAC's "damaged" format is not optimistic.

From MP3 to AAC

As early as 1987, Fraunhofer IIS began the development of “EUREKA project EU147, Digital Audio Broadcasting (DAB)”, which is the predecessor of MP3. In collaboration with Professor Dieter Seitzer, they developed the famous ISO-MPEG Audio Layer-3 compression algorithm. In 1993, this algorithm was integrated into the MPEG-1 standard, and MP3 was put into use. At the end of 1996, Fraunhofer IIS obtained the MP3 patent in the United States, and in 1998 it stated that it would charge a patent fee of MP

3. Since the beginning of 1999, the MP3 format has become popular. In particular, there have been many music websites offering MP3s for free, and MP3 players have flooded into the market like floods. Various factors have made MP3 an extremely mainstream audio format. Although there are VQF, WMA and other challengers, the solid foundation of MP3 makes it still sit firmly at the boss's position.

But the audio format is like computer hardware and software, and it has to be updated, like the tape is not eliminated by the CD? And the CD will be replaced by DVD-Audio. Over time, MP3 is increasingly unable to meet our needs, such as compression ratio behind Ogg, WMA, VQF and other formats, the sound quality is not ideal (especially at low bit rate), only two channels &hellip ;… So Fraunhofer IIS cooperated with AT&T, Sony, Dolby, Nokia and other companies to develop the Advanced Audio Coding (AAC) audio format, which is known as the "21st century data compression method". To replace the location of the MP3. In fact, AAC's algorithm was completed in 1997, when it was called MPEG-2 AAC, because it is still an extension of the MPEG-2 (MP2) standard. But with the MPEG-4 (MP4) audio standard being formed in 2000, MPEG-2 AAC is also the core of its encoding technology, and some new encoding features have been added, so we call it MPEG-4 AAC (M4A).