View Full Version : Finally discovered the hex values!

26th July 1999, 09:50
Hello out there

I now discovered the hex values!

---------COPIED FROM MARKV-------------
Each resolution has one or more standard refresh rates. Each standard refresh rate has a group of parameters associated with it, specified by a group of 24
bytes in the VideoParameters entry. If the resolution has more than one standard refresh rate, you will see 48 or 72 or 96, etc., etc. bytes for the resolution.
Some bytes are grouped into words (16 bits) or longwords (32 bits); when this is the case, little endian applies, meaning the least significant byte comes first
(i.e. you read the bytes right-to-left).
-------------hope it's ok to simply copy it------------
<table valign=top border="1" cellspacing="2" cellpadding="2" bgcolor="#ecbbff">
<tr bgcolor="aqua"><td>value #</td><td>Name in monitor dialog</td><td width="25%"></td></tr>
<tr><td>1+2</td><td>Vertical Refresh rate (Hz)</td><td rowspan=11>

The hex values are calculated backwards I mean the lower byte(s) are entered before the higher byte(s)</P></td></tr>
<tr><td>3+4</td><td>Horizontal Refresh rate (kHz)</td></tr>
<tr><td>5+6+7(+8?)</td><td>Pixel clock</td></tr>
<tr><td>9+10</td><td>Horizontal Front porch (pixels)</td></tr>
<tr><td>11+12</td><td>Horizontal Sync (pixels)</td></tr>
<tr><td>13+14</td><td>Horizontal Back porch (pixels)</td></tr>
<tr><td>15+16</td><td>Vertical Front porch (lines)</td></tr>
<tr><td>17+18</td><td>Vertical Sync (lines)</td></tr>
<tr><td>19+20</td><td>Vertical Back porch (lines)</td></tr>
<tr><td>21</td><td valign=top cellspacing="0" cellpadding="0"><table cellspacing="0" cellpadding="0" border="0">
<tr><td bgcolor="aqua">0</td><td>highest bit</td></tr>
<tr><td bgcolor="aqua">0</td><td></td></tr>
<tr><td bgcolor="aqua">0</td><td></td></tr>
<tr><td bgcolor="aqua">0</td><td></td></tr>
<tr><td bgcolor="aqua">0/1</td><td>Vertical Positive sync polarity</td></tr>
<tr><td bgcolor="aqua">0/1</td><td>Horizontal Positive sync polarity</td></tr>
<tr><td bgcolor="aqua">0</td><td></td></tr>
<tr><td bgcolor="aqua">0/1</td><td>Interlaced</td></tr>
<tr><td>22,23,24</td><td>no related values in the monitor dialog
they are always 0</td></tr>

hope this helps!


[This message has been edited by Helmchen2000 (edited 07-26-99).]

[This message has been edited by Helmchen2000 (edited 07-26-99).]

26th July 1999, 09:54
Looks like you beat me to it, Helmchen! And your version is a lot prettier!

26th July 1999, 09:59
The funniest was that I pressed the submit button in that moment when my mailer tells me of a reply to my previous post


26th July 1999, 12:24
hmm interesting!!

but can u explain
9+10 Horizontal Front porch (pixels)
11+12 Horizontal Sync (pixels)
13+14 Horizontal Back porch (pixels)
15+16 Vertical Front porch (lines)
17+18 Vertical Sync (lines)
19+20 Vertical Back porch (lines)

i know u can get a certain res max refresh by divding horizontal freq by # of pixel horizontally.
for example.. the max refresh of a 95kHz monitor at 1600x1200 is 95k/1200*1.05=75.4Hz
1.05 is for the flyback.

would really like to know the porch thing... http://forums.gagames.com/forums/smile.gif good work guys!

26th July 1999, 19:52
Sorry nickk

but I don't know any things about the relations of these values and as they were represented in the monitor dialog I think it's a good Idea to ask matrox themselves.
I've done this because I was a bit tired of all that guessings about these damn hex-values (should be no criticism on asking about it).
If you can find out something about this, please let me know.


26th July 1999, 22:50
These values are provided to adjust for the differences in timing between the video card and the monitor. When you use the size and position icons in Powerdesk to manipulate the image, this changes these values. Front and back porch seem to deal with how much black border there is around the image. Sync is probably how many pixels/lines to "steal" from the signal for synchronization, although the resolution you get is still the full amount of pixels and lines you asked for.

If I get a chance I'll look this info up on the Web later.

27th July 1999, 13:46
Thanks for the links, O.C.! Now I understand those values a lot better and I can see how they affect the size and position of the image.

27th July 1999, 16:39
Thanks alot on the information on this subject. Here's a link relating to the subject. I think they are both the same.



27th July 1999, 18:06
How do u actually calculate the value...
hori porch and vert porch
front, back and sync...

thanks OC.. very enriching..