259 lines
5.7 KiB
HTML
259 lines
5.7 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
|
|
<HTML
|
|
><HEAD
|
|
><TITLE
|
|
>Fixing Problems with the Image.</TITLE
|
|
><META
|
|
NAME="GENERATOR"
|
|
CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK
|
|
REL="HOME"
|
|
TITLE="X.org/XFree86 Video Timings HOWTO"
|
|
HREF="index.html"><LINK
|
|
REL="PREVIOUS"
|
|
TITLE="Questions and Answers"
|
|
HREF="answe.html"><LINK
|
|
REL="NEXT"
|
|
TITLE="Plotting Monitor Capabilities"
|
|
HREF="cplot.html"></HEAD
|
|
><BODY
|
|
CLASS="sect1"
|
|
BGCOLOR="#FFFFFF"
|
|
TEXT="#000000"
|
|
LINK="#0000FF"
|
|
VLINK="#840084"
|
|
ALINK="#0000FF"
|
|
><DIV
|
|
CLASS="NAVHEADER"
|
|
><TABLE
|
|
SUMMARY="Header navigation table"
|
|
WIDTH="100%"
|
|
BORDER="0"
|
|
CELLPADDING="0"
|
|
CELLSPACING="0"
|
|
><TR
|
|
><TH
|
|
COLSPAN="3"
|
|
ALIGN="center"
|
|
>X.org/XFree86 Video Timings HOWTO</TH
|
|
></TR
|
|
><TR
|
|
><TD
|
|
WIDTH="10%"
|
|
ALIGN="left"
|
|
VALIGN="bottom"
|
|
><A
|
|
HREF="answe.html"
|
|
ACCESSKEY="P"
|
|
>Prev</A
|
|
></TD
|
|
><TD
|
|
WIDTH="80%"
|
|
ALIGN="center"
|
|
VALIGN="bottom"
|
|
></TD
|
|
><TD
|
|
WIDTH="10%"
|
|
ALIGN="right"
|
|
VALIGN="bottom"
|
|
><A
|
|
HREF="cplot.html"
|
|
ACCESSKEY="N"
|
|
>Next</A
|
|
></TD
|
|
></TR
|
|
></TABLE
|
|
><HR
|
|
ALIGN="LEFT"
|
|
WIDTH="100%"></DIV
|
|
><DIV
|
|
CLASS="sect1"
|
|
><H1
|
|
CLASS="sect1"
|
|
><A
|
|
NAME="fixes"
|
|
></A
|
|
>16. Fixing Problems with the Image.</H1
|
|
><P
|
|
>OK, so you've got your X configuration numbers. You put them in
|
|
Xconfig with a test mode label. You fire up X, hot-key to the new
|
|
mode, ... and the image doesn't look right. What do you do? Here's a
|
|
list of common video image distortions and how to fix them.</P
|
|
><P
|
|
>(Fixing these minor distortions is where
|
|
<SPAN
|
|
CLASS="application"
|
|
>xvidtune</SPAN
|
|
>(1) really shines.)</P
|
|
><P
|
|
>You <EM
|
|
>move</EM
|
|
> the image by changing the sync
|
|
pulse timing. You <EM
|
|
>scale</EM
|
|
> it by changing the frame
|
|
length (you need to move the sync pulse to keep it in the same
|
|
relative position, otherwise scaling will move the image as well).
|
|
Here are some more specific recipes:</P
|
|
><P
|
|
>The horizontal and vertical positions are independent. That is,
|
|
moving the image horizontally doesn't affect placement vertically, or
|
|
vice-versa. However, the same is not quite true of scaling. While
|
|
changing the horizontal size does nothing to the vertical size or vice
|
|
versa, the total change in both may be limited. In particular, if
|
|
your image is too large in both dimensions you will probably have to
|
|
go to a higher dot clock to fix it. Since this raises the usable
|
|
resolution, it is seldom a problem!</P
|
|
><DIV
|
|
CLASS="sect2"
|
|
><H2
|
|
CLASS="sect2"
|
|
><A
|
|
NAME="AEN443"
|
|
></A
|
|
>16.1. The image is displaced to the left or right</H2
|
|
><P
|
|
>To fix this, move the horizontal sync pulse. That is, increment or
|
|
decrement (by a multiple of 8) the middle two numbers of the
|
|
horizontal timing section that define the leading and trailing edge of
|
|
the horizontal sync pulse.</P
|
|
><P
|
|
>If the image is shifted left (right border too large, you want
|
|
to move the image to the right) decrement the numbers. If the image
|
|
is shifted right (left border too large, you want it to move left)
|
|
increment the sync pulse.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="sect2"
|
|
><H2
|
|
CLASS="sect2"
|
|
><A
|
|
NAME="AEN447"
|
|
></A
|
|
>16.2. The image is displaced up or down</H2
|
|
><P
|
|
>To fix this, move the vertical sync pulse. That is, increment
|
|
or decrement the middle two numbers of the vertical timing section
|
|
that define the leading and trailing edge of the vertical sync pulse.</P
|
|
><P
|
|
>If the image is shifted up (lower border too large, you want to
|
|
move the image down) decrement the numbers. If the image is shifted
|
|
down (top border too large, you want it to move up) increment the
|
|
numbers.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="sect2"
|
|
><H2
|
|
CLASS="sect2"
|
|
><A
|
|
NAME="AEN451"
|
|
></A
|
|
>16.3. The image is too large both horizontally and vertically</H2
|
|
><P
|
|
>Switch to a higher card clock speed. If you have multiple modes
|
|
in your clock file, possibly a lower-speed one is being activated by
|
|
mistake.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="sect2"
|
|
><H2
|
|
CLASS="sect2"
|
|
><A
|
|
NAME="AEN454"
|
|
></A
|
|
>16.4. The image is too wide (too narrow) horizontally</H2
|
|
><P
|
|
>To fix this, increase (decrease) the horizontal frame length.
|
|
That is, change the fourth number in the first timing section. To
|
|
avoid moving the image, also move the sync pulse (second and third
|
|
numbers) half as far, to keep it in the same relative position.</P
|
|
></DIV
|
|
><DIV
|
|
CLASS="sect2"
|
|
><H2
|
|
CLASS="sect2"
|
|
><A
|
|
NAME="AEN457"
|
|
></A
|
|
>16.5. The image is too deep (too shallow) vertically</H2
|
|
><P
|
|
>To fix this, increase (decrease) the vertical frame length.
|
|
That is, change the fourth number in the second timing section. To
|
|
avoid moving the image, also move the sync pulse (second and third
|
|
numbers) half as far, to keep it in the same relative position.</P
|
|
><P
|
|
>Any distortion that can't be handled by combining these
|
|
techniques is probably evidence of something more basically wrong,
|
|
like a calculation mistake or a faster dot clock than the monitor can
|
|
handle.</P
|
|
><P
|
|
>Finally, remember that increasing either frame length will decrease your
|
|
refresh rate, and vice-versa.</P
|
|
><P
|
|
>Occasionally you can fix minor distortions by fiddling with the
|
|
picture controls on your monitor. The disadvantage is that if you
|
|
take your controls too far off the neutral (factory) setting to fix
|
|
graphics-mode problems, you may end up with a wacky image in text
|
|
mode. It's better to get your modeline right.</P
|
|
></DIV
|
|
></DIV
|
|
><DIV
|
|
CLASS="NAVFOOTER"
|
|
><HR
|
|
ALIGN="LEFT"
|
|
WIDTH="100%"><TABLE
|
|
SUMMARY="Footer navigation table"
|
|
WIDTH="100%"
|
|
BORDER="0"
|
|
CELLPADDING="0"
|
|
CELLSPACING="0"
|
|
><TR
|
|
><TD
|
|
WIDTH="33%"
|
|
ALIGN="left"
|
|
VALIGN="top"
|
|
><A
|
|
HREF="answe.html"
|
|
ACCESSKEY="P"
|
|
>Prev</A
|
|
></TD
|
|
><TD
|
|
WIDTH="34%"
|
|
ALIGN="center"
|
|
VALIGN="top"
|
|
><A
|
|
HREF="index.html"
|
|
ACCESSKEY="H"
|
|
>Home</A
|
|
></TD
|
|
><TD
|
|
WIDTH="33%"
|
|
ALIGN="right"
|
|
VALIGN="top"
|
|
><A
|
|
HREF="cplot.html"
|
|
ACCESSKEY="N"
|
|
>Next</A
|
|
></TD
|
|
></TR
|
|
><TR
|
|
><TD
|
|
WIDTH="33%"
|
|
ALIGN="left"
|
|
VALIGN="top"
|
|
>Questions and Answers</TD
|
|
><TD
|
|
WIDTH="34%"
|
|
ALIGN="center"
|
|
VALIGN="top"
|
|
> </TD
|
|
><TD
|
|
WIDTH="33%"
|
|
ALIGN="right"
|
|
VALIGN="top"
|
|
>Plotting Monitor Capabilities</TD
|
|
></TR
|
|
></TABLE
|
|
></DIV
|
|
></BODY
|
|
></HTML
|
|
> |