Audio compression standard
The MPEG-4 Low Delay Audio Coder (a.k.a. AAC Low Delay , or AAC-LD ) is audio compression standard designed to combine the advantages of perceptual audio coding with the low delay necessary for two-way communication. It is closely derived from the MPEG-2 Advanced Audio Coding (AAC) standard. It was published in MPEG-4 Audio Version 2 (ISO /IEC 14496-3:1999/Amd 1:2000)[ 1] [ 2] [ 3] [ 4] [ 5] and in its later revisions.[ 6] [ 7]
AAC-LD uses a version of the modified discrete cosine transform (MDCT) audio coding technique called the LD-MDCT.[ 8] AAC-LD is widely used by Apple as the voice-over-IP (VoIP) speech codec in FaceTime .[ 9]
^ ISO (2000). "ISO/IEC 14496-3:1999/Amd 1:2000 - Audio extensions" . ISO. Retrieved 2009-10-07 .
^ ISO /IEC JTC 1/SC 29/WG 11 (July 1999), ISO/IEC 14496-3:/Amd.1 - Final Committee Draft - MPEG-4 Audio Version 2 (PDF) , archived from the original (PDF) on 2012-08-01, retrieved 2009-10-07 {{citation }}
: CS1 maint: numeric names: authors list (link )
^ Heiko Purnhagen (2000-02-19). "AES 108th Convention: MPEG-4 Version 2 Audio What is it about?" . Heiko Purnhagen. Retrieved 2009-10-07 . [dead link ]
^ Jurgen Herre, Fraunhofer Institut for Integrated Circuits (2000-03-08), MPEG-4 Low Delay Audio Coding (PDF) , retrieved 2009-10-07 [dead link ]
^ Heiko Purnhagen (2001-11-07). "The MPEG Audio Web Page - MPEG-4 Audio (ISO/IEC 14496-3)" . Retrieved 2009-10-07 . [dead link ]
^ ISO (2007). "Low delay AAC profile - ISO/IEC 14496-3:2005/Amd 1:2007" . ISO. Retrieved 2009-10-07 .
^ ISO (2001). "ISO/IEC 14496-3:2001 - Information technology -- Coding of audio-visual objects -- Part 3: Audio" . ISO. Retrieved 2009-10-07 .
^ Schnell, Markus; Schmidt, Markus; Jander, Manuel; Albert, Tobias; Geiger, Ralf; Ruoppila, Vesa; Ekstrand, Per; Bernhard, Grill (October 2008). MPEG-4 Enhanced Low Delay AAC - A New Standard for High Quality Communication (PDF) . 125th AES Convention. Fraunhofer IIS . Audio Engineering Society . Retrieved 20 October 2019 .
^ Daniel Eran Dilger (June 8, 2010). "Inside iPhone 4: FaceTime video calling" . AppleInsider . Retrieved June 9, 2010 .