Lumagen VisionHDQ - Manual (Page 36)

VisionHDQ ™
User Manual and Installer Guide
© 2004-2007 Lumagen®, Inc. 33 Rev 1.14
Selecting the Output Resolution
The Society for Motion Picture and Television Engineers (SMPTE) standards for 480p, 720p, 1080i
and 1080p are used as reference points for output timing. Other resolutions and vertical-refresh-
rates are derived from these standards.
It is important that the optimal output resolution is selected on the Lumagen. For a DVI-D output
which is connected to a plasma, DLP, or LCD display, the output resolution should be the native
resolution of the display. To find the native resolution of the display, check the user manual
provided with the display. Use the instructions in the Installation Commands section of this
manual to select the appropriate resolution.
For CRT projectors, and other analog interface displays, the best choice of output resolution is
more involved. The best choice depends on tube size, focus, phosphor spot size, and video-
bandwidth. For CRT projectors, some suggested starting points, based on tube size, are 720p for
7 inch, 840p for 8 inch, and 960p for 9 inch. Use the instructions in the Installation Commands
section of this manual to select the appropriate resolution.
High-definition, direct-view and rear-projection televisions typically support 480p and 1080i.
Some also support 540p or 720p. If 720p is supported, it is the recommended resolution,
because 1080i suffers from display interlace-artifacts that reduce the perceived vertical resolution
to roughly the same as 720p. Since the output is over-sampled horizontally, 720p provides nearly
equivalent perceived vertical and horizontal resolution as 1080i, and it eliminates interlaced-
display artifacts.
A vertical-refresh-rate of 59.94 Hertz works well for NTSC and PAL M material. For PAL (except
PAL M) and SECAM, 50 Hertz generally provides the best picture. Note that the selected rate
must be supported by the display at the selected vertical resolution.
NOTE:
The maximum resolution depends on the vertical rate, the output aspect
ratio, and on whether the output size is reduced from factory defaults.
The software attempts to prevent illegal combinations of resolution, vertical rate and aspect ratio,
but given that there are millions of combinations, not all cases could be checked.