AAC Audio and MP3 Audio

Apple Inc. applies FairPlay digital rights management (DRM) technology to regulate protected songs purchased from iTunes Store with iTunes. FairPlay digitally encrypts AAC audio files and prevents users from playing these files on unauthorized computers. AAC songs can be converted to mp3, wma, wav, ogg, and many more formats. Without DRM protection, the converted file can be played in any media player and portable devices.

AAC is also the standard audio format for Sony’s PlayStation 3, Nintendo's Wii (with the Photo Channel 1.1 update installed for Wiis purchased before late 2007) and the MPEG-4 video standard. HE-AAC is part of digital radio standards like DAB+ and Digital Radio Mondiale.

AAC was developed with the cooperation and contributions of companies including AT&T Bell Laboratories, Dolby, Fraunhofer IIS, Sony and Nokia, and was officially declared an international standard by the Moving Pictures Experts Group in April 1997. It is specified both as Part 7 of the MPEG-2 standard, and Part 3 of the MPEG-4 standard. As such, it can be referred to as MPEG-2 Part 7 and MPEG-4 Part 3 depending on its implementation, however it is most often referred to as MPEG-4 AAC, or AAC for short.

M4P is the Protected AAC File. AAC is the audio layer from the follow-on format to MP3. The .M4P extension is AAC purchased from Apple's Music Store (iTune) and is protected by a Digital Rights Management scheme.

Converting AAC Audio to MP3

iTunes Store sells billions of songs every year, accounting for more than 80% of worldwide online digital music sales, most of the songs are in the format of AAC. And these AAC songs are limited by Apple on the usage. That’s why so many AAC audio files owners are seeking solutions to free their purchased songs.

As a leading conversion application of virtual burning, NoteBurner is now being downloaded and used world-widely to convert iTunes AAC audio to mp3, wma and wav, especially in North America and Europe. NoteBurner has also the excellent capability of converting m4a and m4b songs to mp3, wma and wav.

AAC is a wideband audio coding algorithm that exploits two primary coding strategies to dramatically reduce the amount of data needed to represent high-quality digital audio. 1. Signal components that are perceptually irrelevant are discarded; 2. Redundancies in the coded audio signal are eliminated.

AAC offers sampling frequencies between 8 kHz and 96 kHz and any number of channels between 1 and 48. AAC encoders can switch dynamically between a single MDCT block of length 1024 points or 8 blocks of 128 points