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Discussion Starter · #1 ·
Hi,


has anyone had any luck in driving an Infocus 7200 (FW 3.2) from a HTPC via analog VGA at 1280x720 @ 50 Hz? It works fine and pixelperfect at 60 Hz, switching to 50 Hz, the PJ says "720p" and starts showing 1024 of the horizontal pixels only. This effect seems to occure with various 50 Hzish signals. It was the same with FW 2.5.


Olli
 

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Discussion Starter · #3 ·
A more thorough explanation, moved here from a differen thread, where it was off-topic:


@Bob


If the unit is supposed to do 720p at 50 Hz via the analog input, it might just be my incompetence being in the way. Here is what I've tried:


My HTPC is running XP, the gfx card is a ATI Radeon 7000, controlled via PowerStrip. The setup is normally used to drive a Davis CinemaTen at 1024x768 at both 50 and 59.940 Hz. The 7200 (Firmware flashed to 3.2) replaced the C10 on the spot, same cabling and software.


Using Powerstrip, I've enabled the 720p "HDTV standard" resolution at 60 Hz. This works perfectly, the 7200 syncs properly and with a bit of tweaking tracking and phase shift, I can get a checkerboard test pattern to pixel perfection, without any jitter or noise. Playing a movie also works flawlessly there (but please see thread "Motion artefacts on DLPs" for some warbling about temporal dithering in comparision to the C10, an informed statement about dithering/gradient resolution at various vertical refresh rates would probably be appreciated by many people)


When I now change the vertical refresh rate in Powerstrip to 50 Hz, the 7200 again will recognize the signal as "720p", however, instead of displaying 1280 pixels of the input, it only displays about 1024 pixels -- it's not the scaler kicking in, it's just that every 4th pixel or so has a jittery shadow pixel. Fiddling around with phase or tracking doesn't help.


Playing around with the powerstrip porch or sync areas settings can cause the projector to not show "720p", but "1280x720 50 Hz", but the net result is the same.


If I can be of any assistance with further details or experimenting, please let me know.


720p/48 Hz would surely have been of use for me, but since the amount of people with HTPCs short of M1-D adapters is rather limited, don't give it too much priority :) I'm fiddling around with the analog input solely because no M1-D adapter was available on short notice.


Olli
 

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Discussion Starter · #4 ·
For the record, no luck with 720x576 @ 50 Hz either (the resolution and timings are called "720x576 50 Hz (PAL)" in Powerstrip). The unit recognizes this as "800x600 50 Hz".


Olli
 

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I confirm it, i wrote a thread some days ago, 50 hz only works on dvi for me so far. The advantages in smooth pans is huge with pal movies, use dvi if you can, the 50hz also eliminates any red random pixel i had at 60hz.


bye
 

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Discussion Starter · #6 ·
@dubmaster


I really wish I would have been able to try DVI, but I was lacking an M1-D adapter.


Could you perhaps try out whether the unit does 47.952 (or 48 Hz) via DVI properly? Thanks!


Olli
 
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