How to change image size independent of raster size on an XG?

The size and position of the image within the raster are not controlled by the projector, but by the source. The projector just displays the entire raster and whatever's in it. The source determines the image size/placement within the raster via the porches. Larger porches = more "margin" around the image = smaller image.

I have noticed the reference to "porches" on some threads, but it seems to be an HTPC term. What if the source is directly from a digital cable box? Do the newer high end processors provide the equivalent of the porche adjustment?

Why do need to change the size? Changing the original size of an image from the source is altering its resolution. I don't even like to mess with porches as it resizes the image.



Quote:
Originally Posted by CaspianM /forum/post/0


Why do need to change the size?

Click to expand...

Too small porches cause vertical bars to raster/picture, too big porches soften picture and stress horizontal deflection with big resolutions.

You have position (shift) to move V in the raster until it runs out of area then will cause a 'whip' retrace line if you go to far. Check to see if blanking is backed out also. Doug

Decreasing the porches is like increasing the bandwidth of the PJ. The PJ is drawing the whole raster no matter what and it takes time to do this. Why have the PJ waste precious time drawing something that you will not see, this leaves less time to draw the image.


That is one big reason to have a HTPC, controll over the image: porches, refresh rate, gamma...


Deron.


Deron.

A videoprocessor like Lumagen or DVDO will do the job too. Maybe more expensive than a HTPC, but also much more reliable than a computer in being a dedicated device.


Thomas



Quote:
Originally Posted by CaspianM /forum/post/0


Why do need to change the size? Changing the original size of an image from the source is altering its resolution. I don't even like to mess with porches as it resizes the image.

Click to expand...

!? Changing the porches does nothing to the image resolution. It just changes the amount of "dead air" time before/after the image. It will change the size of the image within the raster, but it doesn't change the image itself.


Now if you use a processor to change the porches, I suppose it's possible the processor might rescale or otherwise muck with the picture. But you can change the porches without touching the resolution of the image.