11 Replies Latest reply: Jan 21, 2008 3:20 PM by cjed
cjed Level 1 Level 1 (0 points)

I have a Samsung Syncmaster 206BW (22" wide, 1680*1050 native resolution) plugged on my MDD G4 with DVI (not working with VGA because the Radeon 9000 Pro only manages 4/3 modes in analog).
In the monitors panel settings in OSX (Tiger and Leopard) i see two modes for some resolutions : for example 1024*768 and 1024*768 (extended). However with the two modes the image is stretched to fit the screen. The first (not extented) should add black pixels to around the centered image, and it does'nt work.
So i can't use games in 1024*768 or other 4/3 low res (my G4 can't use the native resolution for games, too much resource heavy).
I tried turning on the monitor after the mac but it is the same, tu non extended mode is managed the same way as the extended mode (stretched).
Is there an utility for mac (as Catalyst Control Center on PCs) to force the monitor to accept unstretched mode ? There isn't any mode setting on the LCD settings. Some say this is a known problem with Samsung LCDs.

Should i return it and buy another LCD ? It this the same with Apple LCD displays ?
I use a Belkin 3m DVI-D wire on both sides.

Thank by advance.

G4 MDD 1,25 Radeon 9000 Pro, Mac OS X (10.5.1), G4 MDD 1,25Ghz Radeon 9000 Pro
  • Malcolm Rayfield Level 7 Level 7 (28,070 points)
    Try setting 1680x1050 with switchResX
    or DisplayConfigX
  • cjed Level 1 Level 1 (0 points)
    Hi, thank you a lot for you quick response, but i can't fix it however.

    I don't think i can change the ratio (select 4/3) in SwitchRes, and the ratio info in DisplayConfigX isn't displayed for my screen ! I only discovered in DisplayConfigX that i can switch from "Extended" to "Synchronization" for the 1204*768 mode (by default setted as "Extended") in the Resolutions tab. Then if I add a new entry (1024*768 Synchronisation) I can set porch values (pixels between and after sync, H and V, width of synch). There seems to be default values for each resolution (different values), and the utility installs a daemon, but i didn't tried it, because i'm not confident about the porch values settings (could lead the screen to stop displaying image at all if wrong values ?)

    Were can we find the timings/porch values for 1024*768, 800*600 and 640*480 modes ? Does the porch pixels settings (area around the centered image) depends from the native screen resolution ,

    Message was edited by: cjed0
  • Malcolm Rayfield Level 7 Level 7 (28,070 points)
    Can you set 1680x1050? Aspect ratio, "Extended" or "Synchronization" shouldn't matter. Exact values of porch blanking shouldn't be critical.
  • cjed Level 1 Level 1 (0 points)
    I can see and use the 1680*1050, in fact this is the only resolution mode that works ok since start. My problem is that i can't play any game in that resolution (99% mac games don't support wide, and even if this would work it would be recent games, and my Radeon 9000 Pro wouldn't support them - or it would be unplayable due to the high resolution leading to very poor fps).

    I can't see the ratio settigns in DisplayConfigX (should be here as in the utility screenshot on the site), the only settings i can use are porch values and "Synchronisation" instead of "Extended" ("Manual" is not available). There is very few documentation for that utility and settings calculations seem very complex.
    I see that on Windows users have to use Catalyst Control Center to switch from wide aspect to 4/3 aspect (that is 4/3 centered image with black areas surrounding it). This is the only way to play old games, or recent games with low resolution, and with correct aspect (for now the image is stretched to fit the whole screen, so not proportionnally, not 4/3).

    Some say that the graphic card driver manages to add black pixels around the centered image in the pixels map sent through DVI to the screen, when non extended mode is selected. It seems there is a problem in OSX, or in the Radeon 9000 Pro driver, or in the card itself.
    Can i be assured the problem can be solved from the computer side ? In the other cas i must return the LCD to the store in less than two weeks... but they don't have interesting 19" LCD to replace it (stretching would lead at least to a correct ration from 1204*768 to 1280*1024, and the stretching is not so bad on the Samsung, ration problem appart).

    Should i add a new entry through DisplayConfigX : 1024*768 Synchronisation in addition to the 1024*768 Extended, to see if that work ?
    Where did OSX retrieve the second mode, 1024*768 (that is non extended), that doesn't work (same result as 1024*768 (Extended)) ? I saw somewhere that there is a display config system file in System/Library (the one DisplayConfigX edits to add/modify listed modes, and the one we must delete if the screen doesn't work after making settings - in Single user mode or with an other screen, my old CRT for example).

    Message was edited by: cjed0

    Message was edited by: cjed0
  • Malcolm Rayfield Level 7 Level 7 (28,070 points)
    You're trying to get the system to run the display at 1680x1050 but tell the game it is 1024 x 768. I don't think OSX has any way of doing that. Can you run the game in a window, which you could set to 1024 x 768?
  • cjed Level 1 Level 1 (0 points)
    Well in fact no, i'm trying to run the game in fullscreen at 1024*768, with the system settings at 1024*768 non extended (one of the two choices in the monitors panel for that resolution, the second being 1024*768 (extended)).

    I don't have to tell the system to do anything, that is the graphic card driver that takes care of turning on or off the upscaling (if off, that is non extended, the graphic card adds surrounding black pixels to the centered 4/3 image before sending it - 1680*1050 final size - to the LCD). It works with many configurations, even macs. Problems are reported with Samsung LCD but the only way to fix it seems from the computer side, editing the display profile settings in the system (through DisplayConfigX). The problem is that it is very difficult to achieve.

    Can this problem be reported to the Apple developpment team (OSX graphic drivers) and Apple Hardware Team if this seems too much technical ? In fact it is also too complex for me, despite being an engineer too, so i think the fix cannot be found easily. Thank you for your support anyway.

    Meanwhile i will try your suggestion, running the game in a window, but performance will be very poor (if ever the option is provided by the game) compared with running in fullscreen.

    Message was edited by: cjed0
  • cjed Level 1 Level 1 (0 points)
    After more investigations I saw that some people say that the black band mode (non extended centered image) only works on laptops, that is a problem in ATIs graphic drivers.
    Some use custom resolution settings, for example 640*400 (that is 16:10 aspect), and then it is being stretched (extended) to 1680*1050 (also 16:10), so finally the image is stretched BUT with right ratio (right aspect). The problem is that games usually don't support such custom resolutions like 640*400. Then for now running in window mode seems the unique solution.

    There is a site that lists tricks to adapt 4/3 games to widescreen LCD (more PC targeted however) :
  • Allan Jones Level 7 Level 7 (32,405 points)
    For what it's worth, I have very limited resolution options when my 22" Viewsonic wide LCD is attached via DVI (using cables provided with the monitor). 1680x1050 works but make things too small for older eyes. Setting any lower size does not look right. If I run off the VGA side using the Apple video adaptor, I have a reasonable choice of wide-screen resolutions. I have the Radeon 9000 64MB that shipped in my G4.

    Games can still be the issue. Unless the game allows custom resolution settings (JK: Jedi Academy does), or can run in windowed node, it get squashed.
  • cjed Level 1 Level 1 (0 points)
    Hi, I agree that finally text is small on a 20" (should be ok on your 22"). However you cannot change the screen pitch (sharper on a 20" but it is said that then the system font smoothing has to be very good - or the result will be worse than with a 22" -, probably the reason why i saw an improvement in reading texts in Leopard from Tiger with the 20" LCD. Apple probably did something to the font smoothing to make it good also on the 20" imac).

    You cannot change the screen pitch, and using a lower 16/10 res (1440*900) implies upscaling it (stretching to fit the screen). Text is larger but the image isn't as good. The solution would be to change the system DPI used for fonts, I heard that resolution independant is present in Leopard to allow same text size whatever resolution used. This is a very common problem, adressed by Apple in Leopard.

    For games, i readed that most games like those using Quake 3 engine (then LucasArts Starwars games) can be tweaked to use widescreen mode through the .ini file (config file).

    Message was edited by: cjed0
  • cjed Level 1 Level 1 (0 points)
    From what i see in the DisplayConfigX documentation :

    A solution could be :
    1) Create a new configuration entry by copying the native configuration (1680*1050 Synchronisation) to have good starting values for porch values. The new configuration will be named "1024*768 non extended" (you must choose "Synchronisation" and not "Extended", it required registrating the utility).
    2) Modify the active horizontal pixels values from 1680 to 1024, and 1050 to 768 for vertical active pixels value.
    3) The H and V porch values (back and front, that is the number of black pixels before and after the centered image) must be increased, each by a half the removed active pixels. So, horizontally we removed 1680-1024=656. Divided by 2 that leads to 328 pixels that must be added to the actual values of H back porch and H front porch. Do the same for vertical porch values : 1050-768= 282, /2=141. So add 141 pixels to actual values of V back porch and V front porch.
    4) Leave the sync (H and V) values as they are. "The syncs don't matter much as long as they are long enough, the beam is not visible during sync. In doubt leave them alone. "
    5) Install the new configuration (install button).

    However the documentation states "corespondingly for bottom overscan (vert front porch vs vertical active) but due to a bug this is fairly limited (apple is working on that)". So perhaps we can't change too much the vertical front porch values. Did Apple fix that problem ? Would be ok if they could provide an utility or advanced parameters in the monitors panel to set the porch values (with a wizard to avoid calculations).

    Message was edited by: cjed0

    Message was edited by: cjed0

    Message was edited by: cjed0
  • cjed Level 1 Level 1 (0 points)
    Problem fixed ! I just installed the provided modes listed/computed by DisaplyConfigX, without editing anything. The non streteched 4/3 are now displayed with the right aspect ratio : in fact the image is stretched to fit the whole screen height, but there is now black areas at left and right. As the upscaling quality is very good i'm pleased with these settings. By editing the modes (increasing the left and right porch values - and adding top and bottom porch values) it should be possible to keep the centered image to the original resolution (without stretching).