Hidden information on some Music Compact Discs – HDCD

The next time your browsing through your compact disc music collection, assuming you still purchase or collect compact discs, have a look for the HDCD symbol on the back of the compact disc box, or on the sleeve notes.


HDCD – High Definition Compatible Digital, or HDCD is a patented encode-decode process, now owned by Microsoft since 2000, that improves the audio quality of standard Redbook audio CDs, while retaining backward compatibility with existing Compact disc players.  Not to be confused with SACD (Super Audio CD), it can only be dedoced on some compact disc players that have HDCD support.

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 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.

But since 2000, Microsoft acquired the company and all of its intellectual property assets and included the technology in Microsoft Windows Media Player.

Windows Media Player 9, 10 or 11 running on Windows XP and Windows Media Player 11 running on Windows Vista or Windows 7 are all capable of decoding and playing HDCDs on personal computers with a 24-bit sound card installed.


Media Player 9 indicates the presence of an HDCD by enabling the logo in the control bar at the bottom of the application window.


This was changed in versions 10 and 11; if an HDCD is inserted into a compact disk player with WMP 10/11 running, the HDCD logo appears only if the HDCD feature is disabled. So again, the HDCD logo only appears if you’ve got it disabled.

To enable HDCD decode on Windows Vista and Windows 7 you need to enable it. Select Tools/Options/Devices/Speakers in Windows Media Player


Does it sound any different, well you have to test it and find out!?

I’ll blog in another post, how you can re-rip all your CDs including this new detailed information!

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