[Balug-admin] video hookup for BALUG presentations at Four Seas Restaurant

[Michael Paoli]

I may want to tweak/update the details on this after 2005-05-17, but from
earlier (2005-04-19) bits of testing and observations, this is what I come
up with for a write-up of our video capabilities at Four Seas Restaurant
(suitable for informing potential presenters of, etc.)

video hookup for BALUG presentations at Four Seas Restaurant

This is what we have available at the Four Seas Restaurant
3rd Floor Banquet Facility "The China Room"
There is relatively high (~20 ft.) ceiling mounted video projector and
screen above the 3rd floor bar area.  Down near the stage area, where
we have access to connect video input to go to the projector, the only
inputs we appear to have available are for composite video, with RCA
type connector.  It seems the video projector just handles NTSC.
BALUG has available to it a USB powered video converter, that takes as
input analog VGA/SVGA via a DE-15M (it also has a pass-through DE-15F
available for external monitor, etc.), and has NTSC SVHS and composite
(RCA plug) video outputs.

Note that this video converter seems to only convert and output to NTSC
video, about the upper left 640x480 of VGA/SVGA input, though it seems
to accept at least some higher resolution inputs (I tried these
resolutions:
1400x1050 1280x1024 1024x768 800x600 640x480)
all of them seemed to provide successful* conversion of the upper left
640x480 region.
Areas of the screen beyond the upper left 640x480 seem to be ignored as
far as conversion goes.  Basic LINUX text console
80x25 text (VGA output) also appears to convert fine*.

Since all this is converted from VGA/SVGA to NTSC, resolution isn't all
that superb.  Also, since there isn't an integral conversion between
input lines/pixels and NTSC scan lines and horizontal resolution, Moire
patterns and other undesirable effects can result with too fine a
detailed pattern.  I'd estimate, for best results, the finest details
intended to be visually resolvable should generally be larger than two
NTSC scan lines ... working back to VGA/SVGA pixels/lines, that would be
three or more lines/pixels, as minimum width/resolution for adequate
projected video resolution.

80*x25 text makes marginally(/barely) readable display.  To the extent
feasible, most objects/text/lines/details, etc. should generally be
larger to make for reasonably readable projected display.

*It may be the converter, and/or the video setup (projector, etc.), but
some of the extreme regions of the 640x480 and/or 80x25 area may be
slightly trimmed or lost somewhere before they make it to the projection
on the screen.  For example, with 80x25 LINUX virtual console text, I
found only about the first 79.5 of the 80 characters of width were
displayed on the screen projection.

Due to resolution limits, distance to screen, etc., most of the general
advice/information about sufficiently large display elements, text, etc.
is probably relatively good advice to follow - or at least pay adequate
attention and consideration to.

references:
http://en.wikipedia.org/wiki/NTSC
http://en.wikipedia.org/wiki/Moire
http://www.fourseasr.com/pdf/3flrplan.pdf
http://www.fourseasr.com/floorplans/3flrplan.gif
http://www.fourseasr.com/
http://www.balug.org/