Sunday, 23 November 2008

What is HDMI? What is HDCP?

HDMI which stands for High-Definition Multimedia Interface is an alternative to SCART (known as PĂ©ritel in France, trapezium shaped connector) and S-Video (analog video signal that carries the signal as two signals, luminance and color, round connector), for transmitted uncompressed digital streams.

HDMI connects digital AV sources to compatible output devices (e.g. television screens, computer screens), it's pure digital, no analog whatsoever. HDMI 1.0 was published in December 2002.

HDCP is the copy-protection scheme for HDMI initiated by Intel and Silicon Image.

Sunday, 2 November 2008

What is WXGA?

WXGA is "wide" XGA, a non-standard resolution derived from the XGA, or Extended Graphics array, standard introduced by IBM in the 1990s - the hardware of which was developed in the UK (for an enumeration of computer display standards see wikipedia). WXGA uses a "widescreen" aspect ratio (ratio of long side to the short side of a display unit).

Metrics for WXGA hardward include luminance in "nits" (an American term for candela per square meters (cd/m^2)); the word derives from the latin nitere (to shine). An average cloudy sky is about 2000 nits, an average laptop screen is about 10 % of that at 200 nits. The moon's surface is about 2500 nits, over ten times brighter than the average laptop screen.

Luminance is also known as luminous intensity or photometric brightness.