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Church and H.O.W. – Forums for HOW Sound and AV - Your Displayed Name Must Be Your Real Full Name To Post In The Church and HOW Forums => H.O.W. AV Archive => Topic started by: fred tatum on January 09, 2007, 01:26:03 AM

Title: DVD Projection
Post by: fred tatum on January 09, 2007, 01:26:03 AM
we are starting a new thing at our church where the announcements are recorded earlier in the week and shown during the services via dvd. when the dvd is projected onto the screen the video looks fine except for a news ticker scrolling on the bottom of the screen is not smooth...it tends to be a little jerky. the tv we monitor the dvd off of shows the ticker fine. here is our setup:

2 computers for powerpoint and a dvd/vhs player feeding into an analog way smf251. the output of the switcher feeds a plasma tv and a sanyo projector. there is a third computer that runs the program that is used to switch between cpu a, b and the dvd player.

the audio for the dvd player and the audio for the computer is fed directly to the console's patchbay and not through the switcher....if you have any more questions, let me know...thank you all in advance....
Title: Re: DVD Projection
Post by: Aaron McQueen on January 09, 2007, 09:53:09 AM
What Sanyo projector do you have?  I believe this problem is related to the response time of the projector, and there is no way to fix it aside from buying a new projector with a better response time, or to stop using the ticker.
Title: Re: DVD Projection
Post by: Brad Weber on January 09, 2007, 10:11:29 AM
How does it look on the plasma display?  It is likely simply artifacts of the scaling and video processing in the scaler and/or projector, that will show up most noticeably on things like sharp edged objects with lots of contrast that are moving, which is exactly what the scrolling text is.

I can't remember if the SF-251A is one of the scalers that locks the output to the PC input settings or if it can have the output set independent of the inputs, but in either case you really want both the PC and scaler set to match the native resolution of your projector.  If not, you end up scaling twice, once at the scaler and once in the projector.

Since it has not been mentioned elsewhere, all LCD and DLP projectors have internal scalers, that is how they can display video images or remap other computer resolutions to their native display resolution.  However, they then need to rescale and resync every time you switch inputs, leading to delays and screen artifacts.  The purpose of a scaler/switcher or seamless switcher is to move this switching and scaling outboard so that you can potentially have a higher quality scaler and can always send the projector it's native resolution so that it never has to switch or resync.  A true seamless switcher uses two internal scalers so that the rescaling of both the current and next selected source is accomplished prior to switching.