Pixel accurate output to SDI?

Anyone any good ideas how to achieve a pixel accurate output on SDI?

Output setup will be:

Catalyst DVI Out (800 x 600 75Hz)

to Folsom ImagePro SDI

from here via SD-SDI to LED-Wall.

My Problem is that the 800 x 600 output will be scaled down to 768 x 576 with matching centers.

If my content moves by 1 pixel it will move less than one pixel on the LED-wall - that means I will get a pixel interpolation (2 pixel active at some percentage of original brightness)

What I will try to do is to scale the image on the ImagePro up and only use the top/left 768x576 pixel of my 800x600 input.
This will require quite alot of manual setup on the ImagePro but should work in theory...

Anyone any better solutions ?

Why pixel accuracy? On LED walls you will achieve better edge contrast and smoother slow movements.

Olli

I would say the route you are thinking of is the best. Yes, it will take a lot of work in the Imagepro, but often times, to get the best, you need to do more setup....

The only other options would be to actually set up the output resolution of catalyst to your desired resolution, which computers dont seem to like very often. Or, you could try running HD-SDI which would give you more resolution. Or, instead of going SDI, do a DVI over Cat5 or Fiber solution, and then just set your raster in the LED wall's processors accordingly. I think this is really one of the only ways to stay truly pixel-accurate. This is why I more often that not decide to have my servers live next to the image processors for the various devices, so I can easily stay DVI the whole way, then network the servers, and run an ethernet line to FOH, hook it up to my laptop, and use that for remote management.

Jason Rudolph

You can even set the DVI-Tag in the ImagePro - but I never tried it with 768 x 576 so far...(and I am not sure it is available...)
The ATI graphics cards are quite flexible in their output resolution.

DVI is no option in this application because my signal will run through a video mixer before getting to the LED wall...

HD-SDI is also no option as the LED wall´s controller only accepts SD signals (... and on the HD side you have a 1920x1200 opposed to 1920x1080 situation...)

Thanks for your reply...

Olli

You could scan convert the output using the image pro to send to the vision mixer and loop thru the DVI to the LED wall processors. The only way of getting pixel accurate stuff is to use DVI. I've just done this on Muse - DVI from Catalyst thru a Folsom Image Pro (using the loop thru) to Barco Encore (which you can program EDID on), sending an SDI signal to Imag. The Encore takes the DVI from Catalyst as a Background layer (i.e. unscaled) and sends that to the LED wall processor. Obviously, you don't need an Encore to do this... Beware if you use the Image Pro to scale you'll lose a frame and a half...

Hugh

just to make things a little more complex - sdi isnt 768x576 its 720x576? - non square pixels - i believe?

its a long and complex scaling chain -

what is the resolution of your output led wall? - in pixels - i just did a show with this signal path - but the output was something like 640x366 pixels - taking an sdi input-

The native LED resolution would have been 1536 x 96 pixels...
...it would have been a four row split on a PAL-canvas - would have done that with four mixes on one screen and Offsets.

Catalyst video content on this LED strip was cancelled this morning - so I don´t have to worry about this any longer for now...

I am not an SDI expert but as far as I know every frame in PAL-SD-SDI consists of 864 x 652 pixels total image size.
Depending on your hardware 720 x 576 or 768 x 576 pixels will be used as active picture area...

Olli