 | This articleneeds additional citations forverification. Please helpimprove this article byadding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "High Definition Compatible Digital" – news ·newspapers ·books ·scholar ·JSTOR(November 2025) (Learn how and when to remove this message) |
 | |
| Media type | Optical disc |
|---|---|
| Capacity | Typically up to 700MB |
| Read mechanism | 780 nm wavelength semiconductor laser |
| Developed by | Pacific Microsonics Inc./Microsoft |
| Usage | Audio storage |
| Extended from | Red Book Compact disc |
| Released | 1995; 31 years ago (1995) |
High Definition Compatible Digital (HDCD) is a proprietary audio encode-decode process that claims to provide increaseddynamic range over that of standardCompact Disc Digital Audio, while retainingbackward compatibility with existingcompact disc players.
Originally developed by Pacific Microsonics, the first HDCD-enabled CD was released in 1995.[1] In 2000, the technology was purchased by Microsoft, and the following year, there were over 5,000 HDCD titles available.[2] Microsoft's HDCD official website was discontinued in 2005; by 2008, the number of available titles had declined to around 4,000.[1]
A number ofCD andDVD players include HDCD decoding, and versions 9 and above of Microsoft'sWindows Media Player on personal computers are capable of decoding HDCD.
HDCD is a favorite among artists who have a preference for high quality sound, such asNeil Young,the Beach Boys and theGrateful Dead—all of whom have multiple CD titles (new and archival) in their catalogs mastered in this process.[3][4]
HDCD encodes the equivalent of 20 bits worth of data in a16-bit digital audio signal by using customdithering,audio filters, and some reversible amplitude and gain encoding:
There is thus a benefit at the expense of a very minor increase in noise.[5]
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.[6]
HDCD technology was developed between 1986 and 1991 by "Prof."Keith O. Johnson and Michael "Pflash" Pflaumer ofPacific 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, visitingSanyo,Burr-Brown Japan and major audio companies, with the intent of licensing the HDCD technology. In 1998, Burr-Brown (now part ofTexas Instruments) and Sanyo Electronics of Japan introduced low-costdigital-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 manyIC makers includingMotorola andC-Cube, allowing HDCD to be offered by mass-market DVD player makers such asPanasonic andToshiba.
In 2000, Pacific Microsonics folded and Microsoft acquired the company and all of its intellectual property.[7][8] Microsoft discontinued the official HDCD website in 2005.
In January 2007, there were roughly the same number of titles available onSACD as on HDCD-encoded CDs.[citation needed]
A number of manufacturers offer players with HDCD capability. Some Panasonic DVD players and theOppo line of players all feature HDCD decoding.[9][10] SeveralYamaha Blu-ray players[11][12] as well asEmotiva CD players[13] decode HDCD.
Since version 9 of Microsoft'sWindows Media Player (WMP), HDCD enabled CDs can be played on personal computers fitted with a 24-bitsound card.[14][15]
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 theDoom9 forum authored a WindowsCLI utility,hdcd.exe,[16][unreliable source?] to extract and decode the HDCD data in 16-bitWAV filesripped from HDCD discs. This utility writes24-bitWAV 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.[17]
Illustrate'sdBpoweramp Music Converter, a WindowsGUI program, has an HDCDDSP effect that acts as a front-end to the utility listed above.[18]
A plugin is available forfoobar2000 that will decode HDCD data in any 16-bitPCM passed through it, resulting in a 20-bit PCM stream.[19]
FFmpeg'slibavfilter includes an HDCD filter as ofFFmpeg 3.1 (June 2016) that will convert 16-bit PCM with HDCD data to 20-bit PCM.[20]
An open-source HDCD decoder library exists aslibhdcd.[21]