 |
| Filename extension | MPEG/3GPP container
Apple container ADTS stream |
|---|---|
| Internet media type |
audio/aac audio/aacp audio/3gpp audio/3gpp2 audio/mp4 audio/mp4a-latm audio/mpeg4-generic |
| Developed by | Bell, Fraunhofer, Dolby, Sony, Nokia, LG Electronics, NEC, NTT Docomo, Panasonic[1] |
| Initial release | December 1997[2] |
| Latest release | ISO/IEC 14496-3:2019 December 2019 |
| Type of format | Lossy audio |
| Contained by | MPEG-4 Part 14, 3GP and 3G2, ISO base media file format and Audio Data Interchange Format (ADIF) |
| Standard | ISO/IEC 13818-7, ISO/IEC 14496-3 |
| Open format? | Yes |
| Free format? | No[3] |
Advanced Audio Coding (AAC) is an audio coding standard for lossy digital audio compression. It was designed to be the successor of the MP3 format and generally achieves higher sound quality than MP3 at the same bit rate.[4]
AAC has been standardized by ISO and IEC as part of the MPEG-2 and MPEG-4 specifications.[5][6] Part of AAC, HE-AAC ("AAC+"), is part of MPEG-4 Audio and is adopted into digital radio standards DAB+ and Digital Radio Mondiale, and mobile television standards DVB-H and ATSC-M/H.
AAC supports inclusion of 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 128 kbit/s (VBR). Tests[which?] of MPEG-4 audio have shown that AAC meets the requirements referred to as "transparent" for the ITU at 128 kbit/s for stereo, and 384 kbit/s for 5.1 audio.[7] AAC uses only a modified discrete cosine transform (MDCT) algorithm, giving it higher compression efficiency than MP3, which uses a hybrid coding algorithm that is part MDCT and part FFT.[4]
AAC is the default or standard audio format for iPhone, iPod, iPad, Nintendo DSi, Nintendo 3DS, Apple Music,[a] iTunes, DivX Plus Web Player, PlayStation 4 and various Nokia Series 40 phones. It is supported on a wide range of devices and software such as PlayStation Vita, Wii, digital audio players like Sony Walkman or SanDisk Clip, Android and BlackBerry devices, various in-dash car audio systems,[when?][vague] and is also one of the audio formats used on the Spotify web player.[8]
- ^ Cite error: The named reference
businesswirewas invoked but never defined (see the help page). - ^ ISO (1997). "ISO/IEC 13818-7:1997, Information technology — Generic coding of moving pictures and associated audio information — Part 7: Advanced Audio Coding (AAC)". Archived from the original on 2012-09-25. Retrieved 2010-07-18.
- ^ Advanced Audio Coding (MPEG-4) (Full draft). Sustainability of Digital Formats. Washington, D.C.: Library of Congress. 22 June 2010. Retrieved 1 December 2021.
- ^ a b Brandenburg, Karlheinz (1999). "MP3 and AAC Explained" (PDF). Archived from the original (PDF) on 2017-02-13.
- ^ ISO (2006) ISO/IEC 13818-7:2006 – Information technology — Generic coding of moving pictures and associated audio information — Part 7: Advanced Audio Coding (AAC) Archived 2016-03-03 at the Wayback Machine, Retrieved on 2009-08-06
- ^ ISO (2006) ISO/IEC 14496-3:2005 – Information technology — Coding of audio-visual objects — Part 3: Audio Archived 2016-04-13 at the Wayback Machine, Retrieved on 2009-08-06
- ^ "The AAC Audio Coding Family For Broadcast and Cable TV" (PDF). 2013. p. 6. Archived from the original (PDF) on 2023-09-28. Retrieved 2024-01-29.
- ^ "Audio file formats for Spotify". Spotify. Retrieved 20 September 2021.
Cite error: There are <ref group=lower-alpha> tags or {{efn}} templates on this page, but the references will not show without a {{reflist|group=lower-alpha}} template or {{notelist}} template (see the help page).