HDCD

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Official logo for HDCD from Microsoft.

HDCD (Abbreviation for High Definition Compatible Digital ) is a technology introduced in 1995 and protected by patents for the coding and decoding of audio data . It was developed between 1986 and 1991 by audio engineers Keith Johnson and Michael Pflaumer .

The procedure

According to the developers, the method is intended to provide a higher quality sound with greater detail and better dynamics of digital audio recordings , especially on CD or DVD , and thus reduce previous disadvantages, especially of conventionally encoded CDs. According to the developers, the effect of greater detail is achieved, among other things, by the fact that the audio information is no longer encoded with a resolution of 16 bits as usual  , but with an equivalent of around 20 bits. This is achieved by placing control signals for an HDCD controller in the lowest bit of the PCM audio signal. This process is called in-band signaling. The HDCD controller controls an expander and can switch between different modes of an interpolation filter.

Terminals

HDCD-capable end devices are rather a rarity on the market for end consumers. This is why the process was designed from the outset in such a way that HDCD-coded audio signals are compatible with conventional playback devices. Since the HDCD control signals are designed in such a way that they only occupy the lowest bit, and that only for a fraction of the total availability, the loss of the useful signal when played on non-HDCD-capable devices is negligible. Therefore, the maximum dynamic range of an HDCD signal is only marginally reduced when played back on a non-HDCD-capable device. When using the optional peak extension, the compressed useful signal is modeled on a tape saturation curve, so that any distortion on non-HDCD-compatible devices is less disturbing than a conventionally mastered CD that has been overdriven to the same volume.

There are both CD players with a built-in HDCD controller, which output a correspondingly decoded audio signal via the analog outputs, and (pre) amplifiers with a built-in HDCD controller, which send the PCM signal via an S / PDIF or HDMI input from any CD player or other source of PCM data. All DVD & BD players can play HDCDs.

The process has so far only achieved limited market coverage. At the moment just about 5000 different HDCD-encoded CDs and DVDs should be available. In addition, the HDCD sound carriers are mostly only released by established and well-known artists.

The future

In September 2000 Microsoft bought the company Pacific Microsonics Inc., which Keith Johnson and Michael Pflaumer had founded in 1996 to better market the process. Microsoft was able to increase the spread of decoder technology due to its market position and the entering into partnerships with end device manufacturers who licensed the technology. Meanwhile, audio / video receivers , digital-to-analog converter , sound processors and digital preamplifier with integrated HDCD decoder available. Microsoft uses the process in its own Windows Media Player to play digital audio formats.

The ability of the system to assert itself with sound carriers remains questionable. The new developments Super Audio Compact Disc (SACD) and DVD-Audio , which already have a significantly higher market share than HDCD-encoded CDs, offer an even greater wealth of detail. The DVD-Audio and SACD store (in different data formats) the higher resolutions of 24 bits used in production with at least 48 kHz. Since it is becoming apparent that the buyers of high-quality sound carriers have turned to these formats (status: 2008), the days of the HDCD process on sound carriers seem numbered.

literature

  • Thomas Görne: Sound engineering. Fachbuchverlag Leipzig in Carl Hanser Verlag, Munich et al. 2006, ISBN 3-446-40198-9 .

Web links

Individual evidence

  1. ↑ Microsoft Acquires Pacific Micro Sonics Inc .: Developer of HDCD Digital Audio Technology to Bring Advanced Sound Engineering To Digital Media Efforts. In: Microsoft News Center. Microsoft Corp., September 18, 2000, accessed January 12, 2010 .