High Definition Compatible Digital

HDCD encodes the equivalent of 20 bits worth of data in a 16-bit digital audio signal by using custom dithering, audio filters, and some reversible amplitude and gain encoding:

• Peak Extend, which is a reversible soft limiter;
• Low Level Range Extend, which is a reversible gain on low-level signals.

There is thus a benefit at the expense of a very minor increase in noise.{{cite web|last1=Johnson|first1=Keith O.|last2=Pflaumer|first2=Michael W.|url=https://www.aes.org/e-lib/browse.cfm?elib=7387|title=Compatible Resolution Enhancement in Digital Audio Systems|date=1996-11-01|publisher=Audio Engineering Society|access-date=2022-12-07|url-access=subscription}}

The claim that the encoding process is compatible with ordinary CD players (without audible distortion) is disputed: not being able to decode the peak soft limiting, a normal CD player will output distorted peaks.{{cite web|url=https://www.audiomisc.co.uk/HFN/HDCD/Enigma.html |title=The HDCD Enigma |publisher=Audiomisc.co.uk |access-date=2022-12-07}}

HDCD technology was developed between 1986 and 1991 by "Prof." Keith O. Johnson and Michael "Pflash" Pflaumer of Pacific Microsonics Inc. It was made publicly available as HDCD-enabled audio CDs (often identifiable by the HDCD logo printed on the back cover) in 1995.

Between 1996 and 1999 Pacific Microsonics VP of OEM Sales, Steve Fields, made over 20 trips to Japan, visiting Sanyo, Burr-Brown Japan and major audio companies, with the intent of licensing the HDCD technology. In 1998, Burr-Brown (now part of Texas Instruments) and Sanyo Electronics of Japan introduced low-cost digital-to-analog converters with HDCD decoding included, allowing HDCD to be used in CD and DVD players in the $100 range. HDCD algorithms were included in DVD chips from many IC makers including Motorola and C-Cube, allowing HDCD to be offered by mass-market DVD player makers such as Panasonic and Toshiba.

In 2000, Pacific Microsonics folded and Microsoft acquired the company and all of its intellectual property.{{cite patent|country=US|number=5479168|pubdate=1995-12-26|title=Compatible signal encode/decode system|assign1=Pacific Microsonics Inc.|inventor1-last=Johnson|inventor1-first=Keith O.|inventor2-last=Pflaumer|inventor2-first=Michael W.}}{{cite patent|country=US|number=5872531|pubdate=1999-02-16|title=Signal encode/decode system|assign1=Pacific Microsonics Inc.|inventor1-last=Johnson|inventor1-first=Keith O.|inventor2-last=Pflaumer|inventor2-first=Michael W.}} Microsoft discontinued the official HDCD website in 2005.

In January 2007, there were roughly the same number of titles available on SACD as on HDCD-encoded CDs.{{citation needed|date=September 2021}}

A number of manufacturers offer players with HDCD capability. Some Panasonic DVD players and the Oppo line of players all feature HDCD decoding.{{cite web|url=http://www.oppodigital.com |title=Universal Network 3D Blu-ray Players - Buy Direct from the Manufacturer |publisher=OPPO Digital |access-date=2012-08-05}}{{cite web|url=http://watershade.net/wmcclain/UDP-203-faq.html|title=Unofficial OPPO UDP-203 Frequently Asked Questions|publisher=AVSForum|access-date=2017-03-03}} Several Yamaha Blu-ray players{{cite web|url=http://hometheaterhifi.com/reviews/video-player/universal/yamaha-bd-a1060-universal-blu-ray-player-review/|title=Yamaha BD-A1060 Universal Blu-Ray Player Review|publisher=Secrets of Home Theater and High Fidelity|date=2016-11-14|access-date=2017-03-04}}{{cite web|url=http://forums.stevehoffman.tv/threads/2-new-yamaha-uni-players-including-one-with-balanced-analog-outputs.566747/|title=2 new Yamaha uni players - including one with balanced analog outputs|publisher=Steve Hoffman Music Forums|date=2016-07-16|access-date=2017-03-04}} as well as Emotiva CD players{{cite web|url=http://hometheaterhifi.com/reviews/audio-player/cd-players/emotiva-erc-3-differential-reference-cd-player-digital-transport-review/|publisher=Secrets of Home Theater and High Fidelity|title=Emotiva ERC-3 Differential Reference CD Player/Digital Transport Review|date=2014-09-02|access-date=2017-03-04}} decode HDCD.

Since version 9 of Microsoft's Windows Media Player (WMP), HDCD enabled CDs can be played on personal computers fitted with a 24-bit sound card.{{cite web|url=http://www.microsoft.com/windows/windowsmedia/player/9series/features.aspx |title=Features of Windows Media Player 9 Series |publisher=Microsoft.com |access-date=2012-08-05}}{{cite web|url=http://www.microsoft.com/windows/windowsmedia/mp10/jukebox.aspx |title=Smart Jukebox Features |publisher=Microsoft.com |access-date=2012-08-05}}

With some HDCD discs and some DVD players using WMP, the first track may not be recognized as HDCD, but all subsequent tracks are. This is because HDCD has a control signal, and if the signal is not detected by WMP at the beginning of the song, the HDCD decoder is not activated.

In 2007, a member of the Doom9 forum authored a Windows CLI utility, hdcd.exe,[http://forum.doom9.org/showthread.php?t=129136 utility]{{Unreliable source?|date=January 2015}} to extract and decode the HDCD data in 16-bit WAV files ripped from HDCD discs. This utility writes 24-bit WAV output files with four bits of padding per sample. The author of the utility decided not to make the source code publicly available as the HDCD technology is patented.{{cite web|url=http://forum.doom9.org/showthread.php?p=1044539#post1044539 |title=HDCD Software Decoder - Doom9's Forum |publisher=Forum.doom9.org |access-date=2012-08-05}}

Illustrate's dBpoweramp Music Converter, a Windows GUI program, has an HDCD DSP effect that acts as a front-end to the utility listed above.dBPoweramp's DSP Effects page [http://www.dbpoweramp.com/dbpoweramp-dsp.htm]; dBpoweramp's local help file

A plugin is available for foobar2000 that will decode HDCD data in any 16-bit PCM passed through it, resulting in a 20-bit PCM stream.{{cite web|url=http://www.foobar2000.org/components/view/foo_hdcd |title=foobar2000 HDCD decoder component |publisher=Foobar2000.org |date=2012-07-18 |access-date=2012-08-05}}

FFmpeg's libavfilter includes an HDCD filter as of FFmpeg 3.1 (June 2016) that will convert 16-bit PCM with HDCD data to 20-bit PCM.{{cite web|title=June 27th, 2016, FFmpeg 3.1 "Laplace"|url=https://ffmpeg.org/index.html#pr3.1|website=FFmpeg.org|access-date=2 July 2016}}

An open-source HDCD decoder library exists as libhdcd.{{cite web|title=libhdcd - An HDCD decoder library|website=GitHub|url=https://github.com/bp0/libhdcd|access-date=21 August 2016}}

• DualDisc
• DVD-Audio
• Extended Resolution Compact Disc (XRCD)
• Super Audio CD (SACD)
• Super Bit Mapping (SBM)

{{Reflist}}

• {{webarchive |url=https://web.archive.org/web/20050622080528/http://www.hdcd.com/ |title=Microsoft's now discontinued HDCD official website}}
• {{webarchive |url=https://web.archive.org/web/20041204171913/http://www.hdcd.com/about/whatisHDCD.html |title=Microsoft's now discontinued HDCD official FAQ}}
• {{cite web|title=HDCD - An Overview|url=http://www.goodwinshighend.com/hdcd.htm|website=Goodwin's High End|archive-url=https://web.archive.org/web/20150402044617/http://www.goodwinshighend.com/hdcd.htm|archive-date=2015-04-02|language=en}}
• [http://wiki.hydrogenaud.io/index.php?title=High_Definition_Compatible_Digital High Definition Compatible Digital] at HydrogenAudio wiki

{{Audio formats}}

Category:Compact disc

Category:120 mm discs

Category:Windows media players

Category:Microsoft Windows multimedia technology

Category:Computer-related introductions in 1995

Category:Audiovisual introductions in 1995

Category:Digital audio storage