DVI input as a texture, not sharp

[mrmacmusic]

Quick question...

Do I need to do anything specific when using a DVI input (Deltacast board) as a texture on a simple rectangle geometry to ensure the rendered output is pin sharp?

Background: I'm using a MacPro to provide separate DVI and SDI input sources whilst building the current Ventuz project here in the studio (when the VBOX goes out it will in fact be fed by DVI and SDI switchers). The MacPro "sees" the Deltacast board as a 1080p display with an overscan option (checked). If I turn off overscan, the texture has black bands around it (no real surprise there). I can change the resolution of the second display on the Mac to various other options (e.g. 800x600, 1024x768, 1600x1200 etc.etc..) but they all still have the overscan option. I find this a bit odd, as this is something I only remember seeing in the past when hooking up a Mac to a television, not a digital display.

If I've just got the Mac desktop background image showing, it looks fine, but when I've got the Mac's System Preferences window open to adjust screen resolutions, and the textured rectangle visible in the Ventuz scene, the text is slightly fuzzy with random discolouration. The problem is the same with or without overscan checked, and changing resolutions doesn't help either.

Any thoughts?

[Karol]

Hi!

To have a pixel to pixel mapping you would need the Overlay Rectangle node.
If you create your own 'overlay' you would have to shift the texture by 0.5;0.5 pixel with the Mapping 2D node (currently not sure in which direction).

Best Regards
Karol

[mrmacmusic]

Hi!

To have a pixel to pixel mapping you would need the Overlay Rectangle node.
If you create your own 'overlay' you would have to shift the texture by 0.5;0.5 pixel with the Mapping 2D node (currently not sure in which direction).

Best Regards
Karol

Thanks Carol, but doesn't the Overlay Rectangle fill the whole viewport? I don't want to do that – I want the DVI source to fill a rectangle geometry that can be scaled, positioned and animated on the canvas. At the moment, the texture derived from my dummy DVI source either has a black border or is cropped depending on the desktop settings on the MacPro source.

[Christian Krix Schmidt]

You only get pinch sharp if you do a pixel for pixel mapping of the input. Otherwise like every other picture scaling in Photoshop you will have a quality reduction. Either it blurs slightly or it is so crisp that it actually produces slight artifacts. If you take an Encore or Spider video system you also have that effect if you scale you DVI inputs. If you reduce the amount of pixels your image/source is displayed in you will always have some sort of scaling effect.

It seems to me that you have more of a problem with your video settings. Discolorations and fuzziness are more problematic i think and probably add to the whole scaling issue. I am no video technician but I would recommend you go back to more basic tests. Do you have the same problem with a Windows machine? Only use proper standard resolutions. 720p50, 720p60 or 1080p30 for example. I remember I used 1280x1024 and 1280x720 a few times during conventions with PowerPoint PIPs. If you have an ImageProHD available, hook only that one up and output 1080p color bars. Do you have ghosting or other visual artifacts? I used Deltacast before and NEVER had that problem so I think it is either settings or source signal that is the problem here.

[mrmacmusic]

You only get pinch sharp if you do a pixel for pixel mapping of the input. Otherwise like every other picture scaling in Photoshop you will have a quality reduction. Either it blurs slightly or it is so crisp that it actually produces slight artifacts. If you take an Encore or Spider video system you also have that effect if you scale you DVI inputs. If you reduce the amount of pixels your image/source is displayed in you will always have some sort of scaling effect.

It seems to me that you have more of a problem with your video settings. Discolorations and fuzziness are more problematic i think and probably add to the whole scaling issue. I am no video technician but I would recommend you go back to more basic tests. Do you have the same problem with a Windows machine? Only use proper standard resolutions. 720p50, 720p60 or 1080p30 for example. I remember I used 1280x1024 and 1280x720 a few times during conventions with PowerPoint PIPs. If you have an ImageProHD available, hook only that one up and output 1080p color bars. Do you have ghosting or other visual artifacts? I used Deltacast before and NEVER had that problem so I think it is either settings or source signal that is the problem here.

Thanks Christian – yes, I'm quite sure it's source signal and/or settings that's the problem and will run more tests including trying other input sources.

I just expected that by selecting a "standard" 4x3 desktop resolution (1024x768 for arguments sake) on the MacPro's output, that it would be auto-sensed by the Deltacast to give a pixel-mapped input and therefore a sharp, unscaled texture?

[Christian Krix Schmidt]

No idea how those boards work. Could be autosensing but I always prefer hard settings so I can be sure it is always the same signal.

[mrmacmusic]

No idea how those boards work. Could be autosensing but I always prefer hard settings so I can be sure it is always the same signal.

Totally agree.... except I can't see anywhere how to fix the settings on the Deltacast side to a particular resolution. There's nothing in the Windows System settings, nor anything within Ventuz itself. Unless I'm missing it?