.AAC File

Files with aac extension are mostly sound files encoded by Advanced Audio Codec. AAC is a lossy digital audio compression format. Because of its exceptional performance and quality, AAC is at the core of the MPEG-4, 3GPP and 3GPP2 specifications and is the audio codec of choice for Internet, wireless and digital broadcast arenas.

AAC was designed as an improved-performance codec relative to MP3 (which was specified in MPEG-1 and MPEG-2) by the ISO/IEC in 11172-3 and 13818-3.

AAC provides audio encoding that compresses much more efficiently than older formats, such as MP3 or OGG, yet delivers quality rivaling that of uncompressed CD audio.

Features of AAC format
AAC was promoted as the successor to MP3 for audio coding at medium to high bitrates. When compared side-by-side, AAC proves itself worthy of replacing MP3 as the new Internet audio standard the advantages over MP3 are:

• Improved compression provides higher-quality results with smaller file sizes.
• Support for multichannel audio, providing up to 48 full frequency channels.
• Higher resolution audio, yielding sampling rates up to 96 kHz.
• Improved decoding efficiency, requiring less processing power for decode.

History of AAC

Advanced Audio Coding was developed with the cooperation and contributions of companies mainly including Dolby, Fraunhofer (FhG), AT&T, Sony and Nokia, and was officially declared an international standard by the Moving Pictures Experts Group in April of 1997.

AAC was written into specification as Part 7 of the MPEG-2 standard, and again into Part 3 of the MPEG-4 standard. As such, AAC can be referred to as MPEG-2 Part 7 and MPEG-4 Part 3 depending on its implementation, but is most often referred to as MPEG-4 AAC, or AAC for short.

However, MP4 usually refers to the format described in MPEG-4 Part 14, which is a container format for carriage of video and audio data.

An aac file extension is associated with the Advanced audio coding file format (AAC) that provides audio encoding with better sound quality and compression ratio than older formats, such as mp3 or ogg.

How to open:

Use any compatible audio player, such as iTunes, Windows Media Player, Winamp, VLC Media Player to playback .aac audio files.

How to convert:

Use any audio conversion tool or transcoder listed in associated applications.