High-Definition Coding

{{Short description|Audio codec}}

HDC (Hybrid Digital Coding or High-Definition Coding) with SBR (spectral band replication) is a proprietary lossy audio compression codec developed by iBiquity for use with HD Radio. It replaced the earlier PAC codec in 2003.{{Cite web |url=http://www.eskimo.com/~nanook/radio/2007/04/am-bandwidth-and-digital-radio.html |title=Radio and WIreless: AM Bandwidth and Digital Radio |access-date=2007-10-07 |archive-url=https://web.archive.org/web/20080607040223/http://www.eskimo.com/~nanook/radio/2007/04/am-bandwidth-and-digital-radio.html |archive-date=2008-06-07 |url-status=dead }}[https://www.osapublishing.org/oe/abstract.cfm?uri=oe-19-26-B895 Optimization of high-definition video coding and hybrid fiber-wireless transmission in the 60 GHz band] In June 2017, the format was reverse engineered and determined to be a variant of HE-AACv1.{{cite web|url=http://theori.io/research/nrsc-5-c|title=Receiving NRSC-5|website=Theori|access-date=14 April 2018|url-status=live|archive-url=https://web.archive.org/web/20170820185827/http://theori.io/research/nrsc-5-c|archive-date=20 August 2017}} It uses a modified discrete cosine transform (MDCT) audio coding data compression algorithm.{{cite book |last1=Jones |first1=Graham A. |last2=Layer |first2=David H. |last3=Osenkowsky |first3=Thomas G. |title=National Association of Broadcasters Engineering Handbook: NAB Engineering Handbook |date=2013 |publisher=Taylor & Francis |isbn=978-1-136-03410-7 |pages=558–9 |url=https://books.google.com/books?id=K9N1TVhf82YC&pg=PA558}}