[mythtv-users] [OT] LCD TV or LCD Monitor for Front-end
Michael T. Dean
mtdean at thirdcontact.com
Tue Jan 31 20:45:31 UTC 2012
On 01/31/2012 02:45 PM, John Welch wrote:
> In my bedroom I
> currently have a Samsung 26" 720p LCD TV connected as a frontend. In
> addition
> to the frontend PC, I also have the TV connected to a cable box and a
> blu-ray
> player.
...
> So, now I've started looking around for a possible replacement. My
> question is
> do I get another LCD TV, or are the LCD monitors that are out there
> now as good
> or better for what I need? I really want to get something capable of
> FullHD
> (1080p), especially since I now have the blu-ray player. I'm strongly
> considering something with an LED backlight, but I guess that isn't a
> necessity if I find something that fits my needs without it. With
> these specs
> in mind I've seen several Acer, Asus, Viewsonic, etc. 27" LED-LCD 1080p
> monitors that consistently get good reviews / ratings in the $250-$350
> range,
> which fits my budget. For LCD TV's I am only seeing a couple of Vizio 26"
> models with similar specs as the monitors in this same price range.
Without having looked into monitors for use in video playback (and,
therefore, without knowing what's available), I will mention that LCD
(including LCD with LED backlight, which--regardless of what the
TV/monitor manufacturers claim--are not LED TVs/monitors***) is a
terrible technology for use with video. Because an LCD pixel is
generally full brightness all the time--rather than starting at full
brightness and dimming over time until the next scan, as was the case
with CRT-based monitors/TVs--there can be quite distinct pixel->pixel
transitions that look "wrong."
Now, because LCD is a terrible choice for video, the industry decided to
come up with approaches to compensate for LCD's display characteristics
to allow them to use LCD for video. Originally, the first generation of
TVs to compensate for LCD characteristics would display the pixel at
full brightness for 1/2 (or some other fraction) of a frame duration and
then display blackness for 1/2 of the duration (so, for a 60fps video,
you'd see the pixel at full brightness for 1/120th of a second and at
black for 1/120th). However, this reduced the brightness of the display
significantly, so some manufacturers started to display full brightness
for 1/2 of a frame, then a dimmed version of the same pixel for 1/2 of a
frame. This reduced the brightness, but not as much as using full
black. Both of these approaches work very well, and due to persistence
of vision, look very "natural." Unfortunately, because there was a
brightness loss (and because brightness in a store display is what sells
a /lot/ of LCD screens) some manufacturers got the idea that it would be
better to invent new pixels--i.e. try to interpolate pixel positions
between frames--and display those at full brightness (so you got 1/120th
second of the pixel specified in the video, then 1/120th second of the
pixel they expected would have existed if the video were 120fps). Some
have taken it farther to try to get to 240Hz (inventing 3 pixels for
every one specified in the video).
Now, regardless of which tech you prefer (and, unfortunately, you don't
get much choice these days as "bigger numbers = better", so most are
using the interpolation technique to get higher brightness), you
probably want to get a display that actually does factor in the LCD's
characteristics when displaying video. It's quite possible you won't
find such workarounds on many/most monitors (as those same ideas would
be awful for non-video computer displays).
Oh, and I'll also mention--although it's probably not a problem these
days--that if you do get a monitor for use with video, you'll want to
make sure it's a 16:9 (= 1920x1080) aspect ratio (rather than 16:10 =
1920x1200). Unfortunately for those of us who do work on computers, the
industry has basically switched production to all 1920x1080 panels, so
you end up paying quite a bit more to get 1920x1200 (and 1920x1200 is
great because it allows, basically, 2 portrait pages (even A4 size) side
by side on the monitor without having to scroll down to see the bottom
of the page and without wasting a portion of the screen size by scaling
width to fit height).
Mike
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