CurtPalme.com Home Theater Forum

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6326 Location: Australia

Ive looked at a few Bluray disc cases, and they say they are in 1920x1080, but how can they be if that is a 1.78:1 ratio and the movie is in 2.35:1?

Wouldnt you be better off running 1920x about 820 or so?

Here is a shot from T2 on Bluray, shot on my computer using VLC media player, and in its original aspect ratio, which came out to 1920 pixels wide, by 817 pixels high.

Doesnt it seem pointless scanning the other 263 lines that are not in use?

benareeno · Joined: 22 Mar 2006 Posts: 1614 Location: ottawa, canada

yes...it is pointless, and it's one of the only big advantages to running an htpc (custom resolutions). That...and low end gamma correction.

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6326 Location: Australia

Only advantages to a computer? I can name a thousand more.

So you just go with what ever resolution is the average for these wider movies and create an entry for that?

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

I use no computer, Ben and his comments Wink

I run 1020x800@72 hz. perfect for BD.

What you want to do is Called Active Area Scanning. here is a nice read.

http://archive2.avsforum.com/avs-vb/showthread.php?t=737385

Nashou

ecrabb · Posted: Thu Jun 24, 2010 11:52 pm Post subject:

Sparky015 · Posted: Fri Jun 25, 2010 12:02 am Post subject:

Good link Nash.

So to wrap my head around this, to get true 2.35:1, you should be running at a resolution of 1020 X 817, which is the native resolution of film. 1920 x 1080 is a 1.78:1 ratio, and is more for HD TV content, but if you have PC or VP, you could scale them all to 1020 x 817 at 72Hz and have 2.35 ratio for everything. Right? Ofcourse, if you have a VP, you can just set memories in it and the PJ and have the best of both worlds assuming you have a screen that can accomodate.

I hope I'm getting this. I'm trying to make sense of this in my head as I get to that point in my theatre build.

Sparky015 · Posted: Fri Jun 25, 2010 12:05 am Post subject:

ecrabb · Posted: Fri Jun 25, 2010 12:07 am Post subject:

Guys, most movies are actually 2.40:1, not 2:35. That's why Nashou suggested 1920x800... That's 2.40.

SC

Sparky015 · Posted: Fri Jun 25, 2010 12:10 am Post subject:

Ok, so stupid question, what's the point of a Radiance then, if an older Lumagen can do this? 1.78:1 content at 72Hz?

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

That's a good point. Letterbox bars are wasted bandwidth. If you can eliminate them from the picture (pardon the pun) then you get a net gain in usable bandwidth.

But you need to have a custom vertical size setting for every different "barless" aspect ratio you set up.

This really makes perfect sense. Simply by not having the projector trace out the letterbox bars, you reduce the number of horizontal
scans per frame from 1080 to (example) 817 lines. That's a savings of 30 percent of your total video bandwidth.

However, this would apply only if there were truly no letterbox bars, seen or unseen. The frame sync data would have to start and stop immediately before and after the picture data. This would be really interesting because then the output signal would technically be a custom format instead of full standards-based HD. It would allow a lower horizontal scan rate and keep up with the frame rate.

CJ

benareeno · Joined: 22 Mar 2006 Posts: 1614 Location: ottawa, canada

I've said this a hundred times, and I'm sure you would all be too afraid to even try it...but you can even show 1.78 content in a 2.35 active scanning area. It only takes off a bit from top and bottom. Most movies look just fine like this...I think home theaters should be based around 2.35 or 2.4 as this should be what provides the best experience....you can then zoom 1.78 or do some sort of compromise where you go a little bigger than 2.4 but not as big as 1.78.

Uncle Buck looks great at 2.35...

Why a radiance you ask? Well..it's the latest and greatest so most people think they need to shell out and buy it. A lumagen DVI will do everything mentioned here...including gamma correction and 47.952 HZ.

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

MikeEby · Joined: 24 Jun 2007 Posts: 5237 Location: Osceola, Indiana

All the buzz in the CIH forum on AVS is how 3D might push out scope. It will be interesting to see how it plays out.

I've ran 1080p72Hz on my 8"NEC and 1980X800p also. On my NEC it didn't look much better then 1080p, frankly I could hardly tell a difference.

Mike

CasetheCorvetteman · Joined: 09 Nov 2008 Posts: 6326 Location: Australia

Thanks everyone for their replies Smile

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

CIR Engineering · Posted: Fri Jun 25, 2010 2:45 pm Post subject:

See my old thread here:

http://archive2.avsforum.com/avs-vb/showthread.php?t=737385

craigr

benareeno · Joined: 22 Mar 2006 Posts: 1614 Location: ottawa, canada

my comment is for someone wanted a properly masked 2.4:1 screen...this person can try watching 1.85 movies in the 2.4 screen and will find out that they look fine. Likely better than making them smaller and more narrow. 2.4:1 movies look infinitely better masked off properly than they do if you watch them on a 16:9 screen...but, that's just my opinion.

Those of you who strive for 4:3 aspect ratio...I have no comment.

MikeEby · Joined: 24 Jun 2007 Posts: 5237 Location: Osceola, Indiana

ecrabb · Posted: Fri Jun 25, 2010 9:05 pm Post subject:

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I think you're questioning a judgement I haven't actually made here.

The issue as I'm thinking of it is something that some of us have seen for ourselves: Attempt to push a projector beyond its bandwidth
limits and the picture can actually soften. Not just fail to fully resolve the picture, but actually get SOFTER as the MTF function goes to crap.

I've seen that for myself. Going full stupid, QXGA resolution (2048x1536) on a Marquee 8000 using a Sencore computer monitor analyzer,
with the refresh rate cranked up to 85 Hz if I remember right. The picture was mighty soft but it did lock right up. However, it was
equipped with a high res P19LNQ green CRT (for test purposes) and when I dropped the refresh rate down, the image got a great deal
sharper.

With regular tubes, the effect was even more pronounced. Go past the video bandwidth capacity and your picture essentially starts
to turn into a blur.

I AM saying, if your picture isn't better looking at 1080p than at 720p, then probably you're better off staying at 720p.

Of course, the optimal answer is to run at the resolution that is highest and still gives good definition, which means a reasonably good
MTF value. But particularly for those of us who can't run custom resolutions and have to choose from the standard resolution options given to us by our sources, we will have to choose from among a limited range of resolution options. In this case I'd say that a clear 720p beats a slightly soft 1080p. Maybe 1080i is best for that PJ.

The user has to make that decision for himself. I'm not saying to not use a higher resolution if it looks better but isn't perfect. I'm
saying, use what looks best to you. It may not be the highest resolution rate available to you.

CJ