CurtPalme.com Home Theater Forum

[VideoGrabber]

Craig wrote:
> The other option on the NEC and Radiance is to run something just below 1080p's 1080x1920. You could crop say 10~15 pixels off the vertical and say 15~30 off the horizontal image area. Then match that on the input using the sizing to maintain perfect 1:1 mapping without scaling to the custom resolutions. <

If I understand what you're saying, this sounds like you're talking about cropping active content. At least, if you're maintaining 1:1 as you indicated.

> This is a similar technique to running 818x1920 for 2.35 movies <

No, with AAS (active-area scanning) you're not cropping any actual content. Here, you would be. But I agree that you could probably get away with it, and the end results of being able to run with proper cadence would outweigh any losses. 30 pixels on the horizontal would be <1% on each side. Probably never noticable. If that's all it took to let you fit your clocks into the bit bandwidth, it would be a good tradeoff.

[CIR Engineering]

[CIR Engineering]

[VideoGrabber]

Thanks, Craig. One other option, assuming you have a quality scaler, sacrifices the 1:1 mapping (which you don't really need on CRT anyway, right?) is to keep all the pixels in the full width and height, so no content is lost, but scale the horizontal area down from 1920 to something more modest.

If your source material is ATSC, you never actually have 1920 anyway. In that case, it's limited to ~1770, based on comprehensive testing that was performed during the evaluation phase. Blu-ray may come closer to 1920, but even there they employ both horizontal and vertical filtering... just not as aggressively as they used to on DVD. HDCam material (which they use on the HDNet series) is limited to 1440 as well. So preserving the full 1920, in many cases buys you nothing.

Thus by dropping the 1920 down to 1800 horizontal (6% lower), you can fit 1080p at 72 Hz into the bit-rate constraints, and in most (all?) cases with no visually perceivable differences (maybe with a test pattern). This was something I suggested to Clarence back a year or more ago, when he was first trying to get 72p to work on his G90. But I never heard if he tried it or not.

The bottom line is that if you've got a good scaler, there are a number of options available to you that you wouldn't have otherwise.

[dvh99]

quick question does the radiance use front porch settings.
and is this needed on a crt.
it says 2200 total so does this simply mean a back porch of 2200-1920.
craig i have looked at the excel file and it says its for no raster ringing on the g90.
does this count for lcp and lugs or is this general for all 9inch crt pjs.
i looked at my powerstrip settings and it gives me a pixel clock of 188mhz so there must be something there to be gained.

dennis

[WanMan]

[CIR Engineering]

[CIR Engineering]

[VideoGrabber]

[Jesse S]

[MikeEby]

[Mark_A_W]

That's really weird.

I tried 1920x804p at 72 hz (active area scanning) and the scanlines in a white area were identical to the fieldlines in 1080i 96hz.

I couldn't tell them apart.

[Spanky Ham]

Mike,
I know someone else who did this with their 135LC and enjoyed it. When he side graded to a G90, he thought the image at that res was as good as 1080p on his G90.

[Jesse S]

[VideoGrabber]

[Jesse S]

My shot accurately depicts what I see standing at the screen. Everyone running 1080i96hz should post a shot so we can see how/if it varies with different projectors.

It's too bad that 1080p72hz has so many problems. It's not fully resolved like a G90/marquee 9500, but the increase in pixel density is very apparent. Running at 1280x720 is much less "fine". Maybe I'll try 1440x900 again.

[mcintoshman]

[Jesse S]

1600x1420 is an odd resolution. It's also too high for an XG unless it's a 4:3 res and you use all of the raster.

Is there any reason you want that res rather than something 16:9 like 1280x720?

[mcintoshman]