D

D-1 resolution

D-1 is a resolution standard for TV specifications. It means 720 x 486 in NTSC systems, and 720 x 576 in PAL and SECAM systems.

dBm

dB(1 mW)

A dBm is a standard unit for measuring levels of power in relation to a 1 milliwatt reference signal. Similar to dB, except that dB is relative to the power of the input signal, dBm always relates to a 1 milliwatt signal. In other words, dB is a relative measurement, and dBm is an absolute measurement.

XdBm = XdBW + 30

dBu

dB(0.775 Vrms)

Voltage relative to 0.775 volts.

Originally dBv, it was changed to dBu to avoid confusion with dBV. The "v" comes from "volt", while "u" comes from "unloaded". dBu can be used regardless of impedance, but is derived from a 600 Ω load dissipating 0 dBm (1 mW).

dBV

dB(1 Vrms)

A logarithmic voltage ratio with a reference voltage relative to 1 volt, regardless of impedance.

Deinterlace

The process of converting interlaced analog video signal into a non-interlaced form.

Digital

A method of storing, processing and transmitting information through the use of distinct electronic or optical pulses that represent the binary digits 0 and 1.

DirectShow

A multimedia framework and API produced by Microsoft for software developers to perform various operations with media files or streams.

Dot crawl

A visual defect consisting of animated checkerboard patterns, which appears along horizontal color transitions. This occurs when the video decoder mixed up the high-frequency luminance information as chrominance information.