Advanced Audio Coding
Lossy audio compression format / From Wikipedia, the free encyclopedia
Dear Wikiwand AI, let's keep it short by simply answering these key questions:
Can you list the top facts and stats about Advanced Audio Coding?
Summarize this article for a 10 years old
Advanced Audio Coding (AAC) is an audio coding standard for lossy digital audio compression. Designed to be the successor of the MP3 format, AAC generally achieves higher sound quality than MP3 encoders at the same bit rate.[4]
| 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; 25 years ago (1997-12)[2] |
| Latest release | ISO/IEC 14496-3:2019 December 2019; 3 years ago (2019-12) |
| 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] |
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 320 kbit/s for 5.1 audio.[citation needed] 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, YouTube Music, Apple Music[lower-alpha 1], 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.[7]