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limitation of PC or projector ...

559 Views 6 Replies 5 Participants Last post by neomagic, Oct 15, 2001

ROne

Discussion Starter · Oct 13, 2001

This is driving me crazy, I have tried - power dvd, win dvd, ati player (the latest version in all cases), I have tried two different graphics cards (Radeon, Geforce 256) and hundreds of refresh rate combinations and resolutions.

But I have two problems that will not go away in any combo.

1) The de-interlacing is awful, the pans in any refresh rate of juddery. I know people talk of absolutely smooth playback but how when these things don't do good 2:2 and 3:2 pull down. Surely no matter what refresh rate you set it not going to make up for substandard re-verse telecine?

There is an inconsitency I have picked up on the different forums, some say 72 hz becuase this is a multiple of 24 which would surely apply on all dvds. And some say 75hz for pal and 60 hz for NTSC, well which is it? Are we sticking to the film or video element of the transfer of the disc.

2) I get a terrible horizontal tearing when ever any fast action happens, like the project can't synch with the pc picture. I have tried cine-masters settings to alter the way it scans the screen and no difference.

I must be missing something because of how people go on about how goog the PC is at a dvd player which is whats kept me going.

Am I wasting my time now pursuing this avenue with this projector, or am I just picky?

Any ideas much appreciated.

PIII 866

815 abit

creative DVD player. DMA ! on

various video cards etc.

toshiba mt-7 in 1280 x 960

Thanks. ROne.

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Frode

· #2 · Oct 13, 2001

1. HTPC suck at de-interlacing. You might have to force a particular de-interlacing method in your player to properly match the source. Refresh rates (independent of PJ):

NTSC film, 71.91Hz

NTSC video, 59,94Hz

PAL film/video, 75Hz

2. Tearing is a pure projector artifact due to the refresh rate of the input signal not matching the internal refresh of the digital projector. Some projectors are locked at a particular refresh (LT150 is locked at 60Hz, I've heard others may use other refresh rates) and so for those you have to figure out what it is, and then use only that refresh rate regardless of the source. If it's variable refresh you shouldn't get any tearing. For DLPs it's quite obvious if they're variable refresh as you'll hear a slight pitch change as the color wheel changes speed if you change the refresh rate. If you do want to figure out what refresh to use download video2000 from www.madonion.com and do a tearing test. Based on that choose the refresh rate that gives the least tearing.

Btw. ATI/Cinemaster has a tweak that gives you slightly better pans at 60Hz for film source. In DVDGenie check 3:2 pulldown reconstruction. If you want to use 71.91Hz instead make sure it's unchecked.

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archtech

· #3 · Oct 14, 2001

Some projectors (PJs) do "look" better than others with DVDs and video source material. Some are more suited for HT use and others are better for the boardroom. Since you've got what you got, though, you should try to get it set up to the best of its abilities. Sometimes this requires a bunch of tweaking.

Have you worked your way through the particular settings in the PJ menu that could possibly be tripping up the display? What are your specs. for your PJ? You're running 1280x960, which is an unusual resolution... 1024x768 and 800x600 are more common resolutions. DVDs are encoded at something like 720x?? or so, so there's always some sort of upsampling. With yours, there may even be upsampling on top of upsampling going on. LCD/DLP PJs always look their best run at native resolutions. You can also try to just use a Default Monitor setup @60Hz instead of a particular *.inf file to begin troubleshooting.

You should post in the LCD/DLP/DILA forum and you'll probably get dozens of replies!

Good luck,

Brian

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clehner

· #4 · Oct 14, 2001

Quote:

NTSC film, 71.91Hz

NTSC video, 59,94Hz

PAL film/video, 75Hz

[/b]

However, the correct refresh rate for NTSC film is 71.928, i.e. multiples of 23,976.

Not all digital projectors accept these exact frequencies but rather operate at a fixed internal frequency of 60Hz which will probably never allow for any smooth scans. There are on the other hand projectors which are perfectly smooth at 71.928 e.g. the Davis Cinema One (which I have).

Cheers

Christoph

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Frode

· #5 · Oct 14, 2001

Thanks Christoph.. my calculations were missing a digit

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ROne

Discussion Starter · #6 · Oct 15, 2001

thanks for your tips guys.

the tosh panel is 1280x960 ao the only way to run it native is using a thru mode that maps the pixels 1-1 leaving a 16:9 window cutting the top off and the bottom, this maps at 1280-720.

The sweet spot for my projector seems to be 75 hz, however instead of getting scanning lines running up the screen, I just get one that sits somewhere in the middle and doesn't move.

This is as goog as I can seem to get, but its not really good enough for viewing.

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neomagic

· #7 · Oct 15, 2001

Thanks Frode! Your explanation helped me a lot since I was suffering from tearing, too. After adjusting the refresh rate with the help of some small tearing test program I figured out what worked best for my projector. I havenÂ´t been able to do the de-interlacing tests with Video 2000, though. All I see there is a black screen.

Another slight problem remains: I canÂ´t seem to get an even refresh rate with Powerstrip (only 59,999), so I wonder how to set the Radeon to the desired frequency (after all Powerstrip seems to be of no use to me anyway).

The sad thing about all this is that I obviously have to do without smooth pans

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