High Definition Compatible Digital (HDCD) is a proprietary audio encode-decode process that claims to provide increased

dynamic range Dynamic range (abbreviated DR, DNR, or DYR) is the ratio between the largest and smallest values that a certain quantity can assume. It is often used in the context of signals, like sound and light. It is measured either as a ratio or as a base ...

over that of standard

Compact Disc Digital Audio Compact Disc Digital Audio (CDDA or CD-DA), also known as Digital Audio Compact Disc or simply as Audio CD, is the standard format for audio compact discs. The standard is defined in the ''Red Book'', one of a series of Rainbow Books (named ...

, while retaining

backward compatibility Backward compatibility (sometimes known as backwards compatibility) is a property of an operating system, product, or technology that allows for interoperability with an older legacy system, or with input designed for such a system, especiall ...

with existing

compact disc player A CD player is an electronic device that plays audio compact discs, which are a digital optical disc data storage format. CD players were first sold to consumers in 1982. CDs typically contain recordings of audio material such as music or audio ...

s. Originally developed by Pacific Microsonics, the first HDCD-enabled CD was released in 1995. In 2000, the technology was purchased by Microsoft, and the following year, there were over 5,000 HDCD titles available. Microsoft's HDCD official website was discontinued in 2005; by 2008, the number of available titles had declined to around 4,000. A number of CD and DVD players include HDCD decoding, and versions 9 and above of Microsoft's

Windows Media Player Windows Media Player (WMP) is the first media player and media library application that was developed by Microsoft for playing audio, video and viewing images on personal computers running the Microsoft Windows operating system, as well as ...

on personal computers are capable of decoding HDCD. HDCD was a favorite for several artists such as

Neil Young Neil Percival Young (born November 12, 1945) is a Canadian-American singer and songwriter. After embarking on a music career in Winnipeg in the 1960s, Young moved to Los Angeles, joining Buffalo Springfield with Stephen Stills, Richie Fu ...

the Beach Boys The Beach Boys are an American rock band that formed in Hawthorne, California, in 1961. The group's original lineup consisted of brothers Brian, Dennis, and Carl Wilson, their cousin Mike Love, and friend Al Jardine. Distinguished by the ...

and the

Grateful Dead The Grateful Dead was an American rock band formed in 1965 in Palo Alto, California. The band is known for its eclectic style, which fused elements of rock, folk, country, jazz, bluegrass, blues, rock and roll, gospel, reggae, world music, ...

, all of whom have had multiple titles in their catalogs reissued in this format.

Technical overview

HDCD encodes the equivalent of 20 bits worth of data in a 16-bit digital audio signal by using custom

dither Dither is an intentionally applied form of noise used to randomize quantization error, preventing large-scale patterns such as color banding in images. Dither is routinely used in processing of both digital audio and video data, and is often ...

ing,

audio filter An audio filter is a frequency dependent circuit, working in the audio frequency range, 0 Hz to 20 kHz. Audio filters can amplify (boost), pass or attenuate (cut) some frequency ranges. Many types of filters exist for different audio a ...

s, and some reversible amplitude and gain encoding: Peak Extend, which is a reversible soft limiter; and 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. 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.

History

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 The Burr-Brown Corporation was an American technology company in Tucson, Arizona, which designed, manufactured, and marketed a broad line of proprietary, standard, high-performance, analog and mixed-signal integrated circuits (ICs) used in elec ...

(now part of

Texas Instruments Texas Instruments Incorporated (TI) is an American technology company headquartered in Dallas, Texas, that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globa ...

) and

Sanyo , stylized as SANYO, is a Japanese electronics company and formerly a member of the ''Fortune'' Global 500 whose headquarters was located in Moriguchi, Osaka prefecture, Japan. Sanyo had over 230 subsidiaries and affiliates, and was founded by ...

Electronics of Japan introduced low-cost

digital-to-analog converter In electronics, a digital-to-analog converter (DAC, D/A, D2A, or D-to-A) is a system that converts a digital signal into an analog signal. An analog-to-digital converter (ADC) performs the reverse function. There are several DAC archit ...

s 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-Cubed, 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. Microsoft discontinued the official HDCD website in 2005. In January 2007, there were roughly the same number of titles available on

SACD Super Audio CD (SACD) is an optical disc format for audio storage introduced in 1999. It was developed jointly by Sony and Philips Electronics and intended to be the successor to the Compact Disc (CD) format. The SACD format allows multiple au ...

as on HDCD-encoded CDs.

Hardware players

A number of manufacturers offer players with HDCD capability. Some Panasonic DVD players and the Oppo line of players all feature HDCD decoding. Several Yamaha Blu-ray players as well as Emotiva CD players decode HDCD.

Software players

Windows Media Player

Since version 9 of Microsoft's

(WMP) HDCD enabled CDs can be played on personal computers fitted with a 24-bit

sound card A sound card (also known as an audio card) is an internal expansion card that provides input and output of audio signals to and from a computer under the control of computer programs. The term ''sound card'' is also applied to external audio ...

. 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.

Other software

In 2007, a member of the Doom9 forum authored a Windows

CLI CLI may refer to: Computing * Call Level Interface, an SQL database management API * Command-line interface, of a computer program * Command-line interpreter or command language interpreter; see List of command-line interpreters * CLI (x86 instr ...

utility, hdcd.exe, to extract and decode the HDCD data in 16-bit WAV files

ripped Ripped may refer to: * Ripped, a slang term for having achieved muscle hypertrophy * '' Ripped: How the Wired Generation Revolutionized Music'', a book by Greg Kot * ''Ripped,'' a series of books and DVDs by Clarence Bass * "Ripped", an episode of ...

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. Illustrate's dBpoweramp Music Converter, a Windows

GUI The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inste ...

program, has an HDCD DSP effect that acts as a front-end to the utility listed above. A plugin is available for

foobar2000 foobar2000 (often abbreviated as fb2k or f2k) is a freeware audio player for Microsoft Windows, iOS and Android developed by Peter Pawłowski. It has a modular design, which provides user flexibility in configuration and customization. Stan ...

that will decode HDCD data in any 16-bit

PCM Pulse-code modulation (PCM) is a method used to digitally represent sampled analog signals. It is the standard form of digital audio in computers, compact discs, digital telephony and other digital audio applications. In a PCM stream, the am ...

passed through it, resulting in a 20-bit PCM stream.

FFmpeg FFmpeg is a free and open-source software project consisting of a suite of libraries and programs for handling video, audio, and other multimedia files and streams. At its core is the command-line ffmpeg tool itself, designed for processing of vid ...

'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. An open-source HDCD decoder library exists as libhdcd.

References

External links

last web archive, Internet Archive capture of Microsoft's now discontinued HDCD official website

last web archive, Internet Archive capture of Microsoft's now discontinued HDCD official FAQ *
High Definition Compatible Digital
at HydrogenAudio wiki {{Audio formats Compact disc 120 mm discs Windows media players Microsoft Windows multimedia technology Computer-related introductions in 1995 Audiovisual introductions in 1995