808/ HTPC problem......

Discussion in 'Desktop & Laptop Computers Forum' started by Rob, Dec 16, 2001.

  1. Rob

    Rob
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    Hi All,

    I know there are many 808 owners here, so maybee you can help me out.

    Just got my PC running, but unfortunately the pj won't lock on. I'm using a Radeon 7500 card, which works fine when connected to a monitor. I've tried various resolutions,and I have had a picture at 480 x 640. I then changed to a custom res of 720 x 1280 or thereabouts , changed the refresh rate to 72hz (NTSC), and got nothing. I now can't even get 480 x 640. I've been buggering about all night , but no joy. No doubt its something very simple, I just don't know what.

    Can anyone help me pleeese?????

    Rob.
     
  2. Phil Hinton

    Phil Hinton
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    Barco PJ's need sync on green before they lock on. You could download Powerstrip and set the sync for green using that, or contact Roland at B4 and ask about a sync box to work between the htpc and PJ, this is what i use at the moment.
     
  3. Rob

    Rob
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    Thanks Phil,

    I have Powerstrip, and have set the polarity of the sync to negative for horizontal and vertical. I know the 808 likes a negative sync. I then tried again and it worked!! Yipee. I then connected up a monitor, to adjust the size a bit, tried again, and nothing. PJ seems very fussy . I will ask Roland about a sync box, I didn't know about these. If you can think of anything that may help, let me know.

    Cheers Rob.
     
  4. Paul D

    Paul D
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    Rob.
    I had the same problem the other week.
    I just deleted all but the "active" block.

    Bingo!, it started to sync to the new resolutions/refresh rates.

    May or may not sort your problem etc!:)
     
  5. Rob

    Rob
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    Thanks Paul,

    Think I'm getting somewhere now. I'm getting a fantastic picture at 800 x 600. Tried the 720 resolution, but it still won't lock. I'm wandering if the card thinks the display can't handle this frequency. The monitor shows a small, distorted picture to one side at this res. Think I need to do a bit more playing. I'll try what you suggested and see how it goes.

    With regard to refresh rates. I've got the PC set to 72, although the PJ shows 73. I seem to be getting a tad more judder than at 60hz, although not terrible, quite watchable. I know there is a magic no 71.xxx any idea what this is, and would it help ?

    Cheers Rob.
     
  6. Rob.Screene

    Rob.Screene
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    Hello Rob,
    With Powerstrip getting the 71.928 reported optimum seems to often require fiddling in the Advanced resolution and timing page (name?). Even after enabling ultra-fine granularity) with the top left from porch and top and bottom extra lines (around the active portion). I have managed to find a combination which doesn't round the number input away from 71.928

    I have 71.928 in the advanced page, the main config page reads it in as 71.929, the resolution pop-up rounds it to 71.9 and I think the Barco screen status text may show something else!

    For me, the secret is getting the 71.928 (Hz horizontal rate) in the advanced screen. Then pans are smooth, even in Star Trek Insurrection. I tried 47.952 but the picture didn't look any better and some scenes showed refresh rate flicker, as opposed to frame judder.

    This has an amlost perfect frame performance and is less tiring than 85Hz, althout 71.928 obviously doesn't work well for PAL films, or any video sourced material.

    I'm back to using Girder and two buttons to switch between

    [email protected]
    [email protected]

    I got this going by allowing girder to create desktop shortcuts and copying the resulting command fromthe shortcut into a Girder Execute command. It seems to work well, just having two buttons on the remote - 1 for Region1 24fps, 2 for PAL/25fps.

    Roland recently managed to focus for scanline gaps on 864 vertical on his second visit and for this particular projector and the desktop looks wonderfully sharp at 960. Hence I'm trying 960 above and whites still look bloomin great to me!

    regards and wishing you a Happy Christmas!,
    Rob.

    References from avsforum:-
    1. "Basically the 71.928/3*2=47.952hz for a frame refresh rate. This gives smooth pans and a stutter free image. "

    2. "I believe the pixmap for PAL DVDs is 768x576. "

    3. "No, I have not tried 48 refresh rate. I have a perfect 71.928 and smooth pans all the time. The gamma level for shadow detail is handled in the player (ThetaerTek) and scoped for 0 IRE level-- which for me is perfect. The G90 likes this rate as well as 1440x960 for a no scaling error environemnt as Dr. Kuo alluded to. "
     
  7. JohnAd

    JohnAd
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    That's wrong it is 720x576. The 768 is the closest square pixel array.

    For PAL you might want to try 1440 as well for lower scaling artefacts.

    In terms of getting exactly 71.928 remember if you are .01 out you are you are causing an adjustment every 12 minutes so you want to be close but don't worry if it is not exact. I seem to remeber it is impossble to get it exact but iit is possible to get pretty close. Also the timing is normally done by the sound card clock so you may get more judder than suggested by my fag packet calculation above. So maybe you also wnatto try one up and one below from the ideal to see if it reduces judder.

    John
     
  8. Rob.Screene

    Rob.Screene
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    Thanks John.

    I had previously read PAL DVD's were 720x576, but thought people on the avsforum were never wrong!

    I'll give [email protected] another go tonight then, just after I put those sleek, matt black painted covers back on the Barco!

    cheers,
    Rob.

    p.s. What do you think is the best pixel size dScaler setting is for Playstation2 PAL Gran Tourismo 3 then? Again, I'd probably be displaying that at [email protected] Perhaps I should drop the res to get 100Hz vertical?
     
  9. JohnAd

    JohnAd
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    Rob

    If only the avsforum people were never wrong. I'm getting a bit hacked off with it over there, the signal to noise seems to have gone through the roof with lots of people jumping on any thread to spout the same old nonsense. Not like in the old days, luckily there is here :)

    With the PS2 I would play with 720, 640, 480 and 360 to see which one seems to be the native rate, get a detailed screen and try and find the width were the pixels seem best defined with no grey on a black/white transition. Also I would guess that the PS2 is only doing 25Hz updates so 75 should be OK but 100Hz might be better.

    John
     
  10. Rob.Screene

    Rob.Screene
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    Will do.

    Black/White transition? Well I could with Video essentials, but DVD playback mode is probably not the same res as the games native mode?

    I'll play with the input res options a bit more. Ah joy!

    Let me just say that Gran Tourismo 3 via de-interlaced dScaler Greedy and a Radeon scaled output onto a 6 foot [email protected] Barco 808s projected screen is truly superb. The bounce and orbiting should prevent excessive CRT wear too, even if the game pops up a bright bit of text, which is doesn't seem to do for very long, unless left on a menu. Literally larger than life! What dScaler does with this limited source is truly amazing. Thanks.

    Rob.... I've just thought, you write the resolutions as VerticalxHorizontal, which I think is unusual. Are we clear that it's 720 vertical were talking about here. If you get them the wrong way the 808 may hit it's limits?

    regards,
    Rob.
     
  11. JohnAd

    JohnAd
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    By balcka nd white transition I just meant any clearly defines edge where one block is one colour and the next block is another colour perferably very differnt brightness.

    eg orginal image 00008888 should be 00008888 on screen rather than 000448888 or 00048888 or 00004888.

    John
     
  12. NickBull

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    If you go into the custom resolutions part of Powerstrip and set up a new resolution, there's a couple of tick boxes for positive sync, these need to be un-ticked otherwise you won't get a picture. (doublt check this, but I think a tick is positive Sync!)

    Nick
     
  13. tryingtimes

    tryingtimes
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    Rob - it might be the old monitor choice problem here. I got this until I told the graphics card that I was using a sony widescreen monitor (the model no. is in another thread). It then was ok.

    Mine still won't manage 1440x720 which is a shame - it should be possible - I'll look at it again sometime (Roland's coming to calibrate tomorrow though)
     
  14. Rob

    Rob
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    Thanks for all your help. Yes I think the monitor choice could be responsible with regard to a distorted picture. I'll get a decent one, hopefully once thats clocked in things should change.

    I'll try the refresh rates/ timings. I guess its something we all have to try for ourselves. Nice to hgave an idea of where to start though!

    Thanks guys.
     

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