HD or High Definition is the new
generation of display device, most usually used in the sense of
HDTV. With the ever increasing data transfer rates afforded by
cable technology what was once a dream in now becoming reality
with a number of HD channels already available here in the UK
from the BBC & Sky. HD essentially involves improving the
resolution that images are viewed at which means better, clearer
pictures.
Standards for HD dictate that the minimum native resolution of
the display is 720 physical lines in wide aspect ratio. (This
is compared with 576 visible lines in old style STANDARD DEFINITION
displays.) In the world of computers & projection technology
a line equates to a line of pixels and therefore an HD projector
will have a native resolution of 1280 x 720 (progressive) or 1920
x 1080 (interlaced). It should be able to display these at both
50Hz & 60 Hz.
The required input formats for HD are as follows:
Analog
YPbPr (Component Video)
DVI
( with HDCP) or HDMI (with HDCP)
Some Definitions:
HD vs HD Ready - HD devices
have a built-in tuner whereas HD Ready devices require an external
tuner. HD Ready devices offer only to meet a minimum specification
and are generally not true HD display devices.
DVI - Digital Video Interface
HDMI - High Definition Multimedia Interface. HDMI is the
latest standard connector designed for digital TV. Unlike DVI
the connector also carries audio.
HDCP - High-bandwidth Digital-Content Protection
Progressive vs Interlaced - These are the types of video
scan used to create the images onscreen. A progressive video scan
involves scanning (displaying) the image each line at a time from
top to bottom. Interlaced scanning (as used in CRT display devices)
invloved splitting the lines onscreen into two "fields",
where alternate lines belong to different fields. The first field
in written, followed by the second field which then completes
the "frame". The reason for using interlaced scanning
is that it provides far reduced flicker at any given frequency
of scan. In older equipment this was an issue. Modern equipment
uses Interlaced video as a form of compression as it can approxiamately
half the data transfer rate required.
HDV - High Definition Video - More generally used in cameras
which are recording to HD standards.
REAL LIFE
USAGE
HDTV is now coming online and HD technology does offer a great
image quality. It is worth carefully considering whether buying
an HD Ready unit will actually meet your full future requirements,
although it will offer an improvement over SDTV.
We have range of HD equipment in our hire & demo stock.
Please call or email us for further details.
We'll be happy to hire, demonstrate
our HD stock. Please call or email for current purchase price.
Current hire prices are shown below.
| Samsung DVD-HD860 | High Definition (HD) DVD player. Can convert standard DVD image quality to High-Definition level. HDMI output, upscaling, etc. | £10.00 | £30.00 |
For more info on the Canon XEED SX50
Projector click here
MORE INFO
For more detailed info on HD, HDTV & HDV click
here for wikipedia defintion
