CurtPalme.com Home Theater Forum

StuntDummy · Joined: 08 Aug 2007 Posts: 59 Location: San Francisco, CA

I have read in this forum that 1280x960P may be a good resolution to run on my G70. I am guessing that the best route would be to down convert from 1080P but the problem is my scaler will not input 1080P. So will going from 1080i to 1280x960P look decent?

dvh99 · Joined: 25 Dec 2009 Posts: 2158 Location: nederland

1280*960 is 4:3 aspect ratio, try 1280*720.
i do not see why 1080i wont work btw as the 1280*720 runs at a higher pixelclock then 1920*1080 interlaced.

ecrabb · Posted: Thu Feb 03, 2011 5:32 pm Post subject:

For film-based sources, scaling from 1080i should work well. In fact, it should inverse telecine and even give you a nice clean 48hz or 72hz output...

But, I question the use of 1280x960. First, it's 4:3... If we're talking 16:9 (for blu-ray), and if max resolving power is the goal, 1280x720 would make more sense. 720p is plenty sharp on the G70, but also well below of what it's capable of resolving with good MTF, so 1280 and 720 are both way too low IMHO...

Now, while the G70 can't quite fully resolve 1080p, I'm not sure it makes a lot of sense to throw away resolution in the digital domain just so you can resolve fully the resulting sub-sampled image. To me, that's like turning down the sharpness on your TV just because your eyes aren't as good.

IMHO, I'd run full res, and if you're going to do anything with your scaler, run active area scanning for scope movies - 1920x800 - and see how that works.

For what it's worth, I run 1080p/60 on my G70 and I love it. I haven't even really felt like going to the expense or trouble to get into scaling or anything because I'm very happy with what I have.

SC

draganm · Joined: 08 Mar 2006 Posts: 8990 Location: Colorado

this has been discussed before, I think Scott was the first to point it out, as you go higher in rez what you lose the most is CR. As you increase resolution and/or sweep rate the time for beam on/off is decreased so the peaks get rolled off. This is more true for 8' inch tubes VS. 9 inch tubes because your total "dwell time" on the Phosphor face between retrace is less so the beam has to be modulated even faster.
the only factors that can change this is more capable electronics, (modifed/upgraded video or deflection circuitry), or liquid coupling on an 8 inch as the "scatter" and refraction of the beam in the air-gap is reduced.
I really love 720P on my Marquee 8500 and I can see the scan laines from about 6 or 7 feet back. At 9 feet back they are not visible to my eyes and the ANSI is as good as it can get for an 8 inch AC machine. On a G70 with LC optics I would expect the ANSI to be equal or even better at higher resolutions (optics compensating for decreased electron beam dwell time).

Spanky Ham · Joined: 22 Mar 2006 Posts: 5643 Location: Comedy Central

1280x960 is a res from the Old Republic, wait I mean DVD. Smile

If you are watching DVDs, then you could make an input with this res for that purpose. If you are watching HD, then better options have been mentioned.

StuntDummy · Joined: 08 Aug 2007 Posts: 59 Location: San Francisco, CA

Yes 16:9 is what I want. Thanks for the clarification. I have the projector set up at 1080p now, and yes it does look pretty damn good, I just wanted to see what the difference in sharpness would be, that was before I knew that I was (essentially) asking about 720P Confused

Some times I think too much.

ecrabb · Posted: Thu Feb 03, 2011 7:11 pm Post subject:

Well, if you have a scaler and want try to a little lower resolution, you could drop down to something higher than 720p, but lower than 1080p... Something like 1520x855... The projector would resolve that better, and test patterns may look a little sharper. But, again... In principle, I'm not sure it makes a lot of sense to throw away resolution in the digital domain just so your analog device can display the sub-sampled picture better. But, some people are of the opinion it looks better, so give it a whirl and let us know what you think!

SC

CIR Engineering · Posted: Thu Feb 03, 2011 8:57 pm Post subject:

stefuel · Posted: Thu Feb 03, 2011 11:35 pm Post subject:

If you still have a hot nut for 960P and wish to do it in a widescreen format, the try 1440X960P
Pre BR HD I was scaling SD DVD to that via SDI. The image was great. However, to simplify things conectivity wise everything (DVD & BD) goes straight to 1080P 60.

ChrisWiggles · Posted: Fri Feb 04, 2011 1:21 am Post subject:

Also, if you are doing a standard-definition DVD setup only, using 1440 as your horizontal resolution rather than 1280 is superior as its an even multiple of the non-square sampling aspect ratio of NTSC.

For HD, then 1280 is the correct horizontal resolution to use.

StuntDummy · Joined: 08 Aug 2007 Posts: 59 Location: San Francisco, CA

Thanks for the input on the output fellas. I will definitely try some of those when I am able to pull myself away from the 1080p Blu-rays that seem to pop on every time I get near the projector.