Advanced Audio Coding (
AAC) is a standardized,
lossy compression and
encoding scheme for
digital audio. Designed to be the successor of the
MP3 format, AAC generally achieves better sound quality than MP3 at similar
bit rates.
AAC has been standardized by
ISO and
IEC, as part of the
MPEG-2 and
MPEG-4 specifications. The MPEG-2 standard contains several audio coding methods, including the MP3 coding scheme. AAC is able to include 48 full-
bandwidth (up to 96 kHz) audio channels in one stream plus 16 low frequency effects (LFE, limited to 120 Hz) channels, up to 16 "coupling" or dialog channels, and up to 16 data streams. The quality for
stereo is satisfactory to modest requirements at 96 kbit/s in
joint stereo mode; however,
hi-fi transparency demands data rates of at least 128kbit/s (
VBR). The MPEG-2 audio tests showed that AAC meets the requirements referred to as "transparent" for the ITU at 128 kbit/s for stereo, and 320kbit/s for 5.1 audio.
AAC is also the default or standard audio format for:
Apple's
iPhone,
iPod,
iTunes,
Sony's
PlayStation 3 and is supported by
Sony's
Playstation Portable, latest generation of
Sony Walkman, phones from
Sony Ericsson,
Nseries Phones and the latest S40 models from
Nokia,
Android based phones,
Nintendo's
Wii (with the
Photo Channel 1.1 update installed for Wii consoles purchased before late 2007), the
Nintendo DSi and the
MPEG-4 video standard
'
High-Efficiency AAC' is part of
digital radio standards like
DAB+ and
Digital Radio Mondiale.
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