[simpits-tech] Re: Projector Screen

[Marv De Beque]

Okay.  Sounds like if you plan on using something like a DLP projector with
a native XGA 1024 by 768 pixel resolution you don't need a scaler.

However, if you plan on using a video out from a tuner, etc., then a scaler
makes perfect sense.

Do I have that right?

Marv



On 10/20/03 4:04 PM, "Jim K." <JimK at sisna.com> wrote:

>>>>>>> From: Marv De Beque <mdebeque at woh.rr.com>
> Subject: Re: [simpits-tech] Re: Projector Screen
> To: Simulator Cockpit tech list <simpits-tech at simpits.org>
> Message-ID: <BBB976D4.5E79%mdebeque at woh.rr.com>
> Content-Type: text/plain; charset="US-ASCII"
> Exactly what do these scalers do (CPU based and stand alone)?
> Marv<<<<<<<<<<<<<<<<<
> 
> 
> Marv,
> Here is a real generalized overview of scalers.
> 
> A video scaler basically increases the number of horizontal line scans in a
> video image.   A basic U.S. NTSC television has 480 lines of video
> image.   Thats OK fine for a standard tv screen size but if you project
> that same image and increase its size to fit a home theater (HT) wall size
> screen you will see a line of video, then a blank line then a line of
> video, etc.   You will see those blank lines easier the closer you get to
> the screen.   Normally you can see them when you are 15 feet or closer to
> the screen.   At 15 feet the video will look fuzzy and the closer to the
> screen you get the more you will actually be able to see the individual
> scan lines.     Its like looking through blinds to see the video.  So 480
> lines is not very impressive to  watch on a large screen like a 115"
> diagonal HT screen where you are sitting 12 to 15 feet away from the screen.
> 
> Since HT video projectors are capable of projecting HiDef signals HT people
> use a video scaler to increase the number of horizontal video scan lines
> coming out of a satellite tv receiver, computer or a DVD player.   Although
> most HT people don't use sat tv as a video source since its video quality
> is really terrible and not worthy of projecting onto a big screen.  Its far
> to compressed to provide high quality video.  :-)))    But many HT users
> will use HiDef sat receivers or local HiDef antennas to project HiDef and
> that looks awesome on a HT screen.   Even a standard DVD video won't look
> very good when projected to a large HT screen.
> 
> Every scaler is capable of scaling to different resolutions (lines of scan)
> and with different overall video quality depending on the quality of the
> scaler.   I scale my DVD and sat tv signal to 720 lines of resolution then
> send it to my CRT projector and then onto my HT screen.   I also have a
> HiDef receiver but that doesn't need scaling since its already at a true
> 1080 lines.
> 
> The scaler basically looks at 2 consecutive horizontal lines of video and
> the blank line in between them.  It then determines what would be in that
> blank line if it had video and puts in a video scan line.   As you increase
> the number of scan lines the picture quality will go up until you reach a
> threshold which is dependent on your equipment and original video
> signal.   This scaling system works pretty well and when you look at a
> scaled large screen you won't see any scan lines even if you get real close
> to the screen.
> 
> True HiDef video is 1080 lines of video.   It is far better than DVD video
> and is much, much better than any signal scaled to 1080 since each scan
> line is a true scan line and not an interpreted scan line like scalers
> provide.   So there is a great deal of projected video information and
> everything looks VERY crisp, clear and detailed.
> 
> If you are using a projector you almost have to use a scaler to get a good
> picture especially if are sitting close to the screen.   As I mentioned you
> can go the computer scaler route or go with a dedicated scaler.   There is
> a Viewsonic VB50 that that sells for about $80 that would probably work
> with games.   Many HT people use scalers that cost  $1500 and up.   There
> are some scalers in the $400 range but you get what you pay for and HT
> people are looking for extreme high quality since they spend a lot of time
> and money in their systems (video and audio) and theater room.
> 
> If you are thinking of going the projector route look at a CRT since it
> blows away digital projectors and plasmas.
> 
> Jim
> 
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