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Q P E G F A Q
~~~~~~~~~~~~~~~~~
Frequently Asked Questions about QPEG
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Table of Contents
~~~~~~~~~~~~~~~~~
1. I can't get QPEG to work with my graphics card. What can I do?
2. QPEG displays images greyscaled only. How do I get color?
3. I'm using the VESA driver. 16 and 256 color modes work, but I can't get
hicolor or truecolor. What's wrong?
4. Is it possible to switch off that annoying beep?
5. When zooming or panning across large images, the bottom part is
distorted. Why?
6. When I try to zoom or pan, the screen turns black. What happened?
7. Will there be a Windows version?
8. Why is the menu screen only black and white?
9. Why do I get only greyscaled images in 16 color modes?
10. Color dithering in 256 color modes looks bad. Why?
11. It takes so long to read a directory from a CD-ROM. What can I do?
12. Which configuration file should I use?
13. VESA - what's that?
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Question 1:
~~~~~~~~~~~
> I can't get QPEG to work with my graphics card. What can I do?
First of all, perhaps QPEG can work with your graphics card, but you are not
using the right configuration file. For more information about choosing the
right configuration file please refer to the answer of question 12.
Sometimes none of the existing configuration files works with a special
graphics card. In this case there are several ways:
1. Use one of the VESA configurations if possible. Please refer to
question 13 and its answer for more information about VESA.
2. Use the standard VGA configuration (STDVGA.CFG).
However, this provides only a very small number of video modes.
3. If you are an experienced programmer, you can create a video driver
yourself. Of course you must have some information about your
graphics hardware. Read the file DRV.DOC for more information about
how to create a QPEG video driver.
------------------
Question 2:
~~~~~~~~~~~
> QPEG displays images greyscaled only. How do I get color?
By default, QPEG uses the video mode 640x480x16 which only offers
greyscaled display.
To change the mode, use the '+' and '-' keys while in the directory screen
(not while viewing an image!). Watch the status line in the upper window:
it tells you the currently selected resolution and number of colors.
Hit the '+' key until it says at least '256 colors'. Be sure not to be in
greyscaled mode (if the status line says '<grey>', use the '$' key).
Now QPEG will display images in color.
You can change the default video mode by editing the initialization file
QPEG.INI. For that purpose you can use any standard ASCII text editor
(e.g. EDIT which is supplied with MS-DOS 5/6). Please read the comments
in QPEG.INI, and you will be able to change QPEG's defaults.
------------------
Question 3:
~~~~~~~~~~~
> I'm using the VESA driver. 16 and 256 color modes work, but I can't get
hicolor or truecolor. What's wrong?
In order to be able to use hicolor and truecolor modes with the VESA driver,
your VESA BIOS (or VESA VBE/TSR) must be at least version 1.2.
Versions prior 1.2 of the VESA standard did not define hicolor and truecolor
modes.
(Use the VESATEST program to get the version of your VESA VBE/TSR).
Try to get UNIVBE or UNIVESA. These are TSRs (i.e. programs that stay
resident in memory) which make your BIOS VESA 1.2 compatible. They are
available from most major PD/Shareware sources.
------------------
Question 4:
~~~~~~~~~~~
> Is it possible to switch off that annoying beep?
Yes, you can do that by editing the initialization file QPEG.INI.
For that purpose you can use any standard ASCII text editor (e.g. EDIT
which is supplied with MS-DOS 5/6). Please read the comments in QPEG.INI,
and you will be able to change QPEG's defaults.
------------------
Questions 5 and 6:
~~~~~~~~~~~~~~~~~~
> When zooming or panning across large images, the bottom part is distorted.
Why?
> When I try to zoom or pan, the screen turns black. What happened?
Two questions, one answer: there's not enough XMS/EMS memory.
QPEG stores the decoded image in XMS/EMS memory (if such memory is present
at all). When zooming or panning, QPEG copies the visible part of the image
back from XMS/EMS to video memory.
If you don't have any XMS/EMS memory at all, the screen will turn black.
If you have XMS/EMS memory, but it's not enough for the image, the bottom
part will look distorted. Remember that in truecolor modes each pixel
takes three bytes (so a 640x480 image needs 900 Kb), in hicolor modes
each pixel takes two bytes, in 256 and 16 color modes each pixel takes
one byte.
How to solve the problem? Well, there are several ways:
- Don't use panning/zooming.
- Use a video mode with less colors. For example, in 256 color modes
an image takes half the memory as compared to hicolor modes.
- Free some XMS/EMS memory. For example, if you have installed a RAM disk
or disk cache program, removing it may give you some more memory.
- Buy more memory.
------------------
Question 7:
~~~~~~~~~~~
> Will there be a Windows version?
A Windows version is currently under development, but it won't be released in
the near future.
The current version of QPEG runs in fullscreen mode under Windows 3.1 and
OS/2 2.1. Under certain circumstances the display doesn't work correctly
under Windows (that's probably the fault of Windows). There's usually less
XMS/EMS memory available when started under Windows or OS/2, so you may not
be able to pan across larger images.
------------------
Question 8:
~~~~~~~~~~~
> Why is the directory screen only black and white?
I'm using the 640x480 video mode with 16 colors for the directory/menu
screen, because it's a standard VGA mode common to all VGA cards.
See the next question.
However, it is possible to use a 256 color mode for the directory sceen
by changing an entry in the QPEG.INI file, but you must be absolutely sure
that the mode 640x480 with 256 colors works fine with your graphics card.
(The entry to be changed is "Interface_256_Colors".)
------------------
Question 9:
~~~~~~~~~~~
> Why do I get only greyscaled images in 16 color modes?
16 colors are way too few to display truecolor images. That's why QPEG
displays images greyscaled when in a 16 color mode.
------------------
Question 10:
~~~~~~~~~~~~
> Color dithering in 256 color modes looks bad. Why?
QPEG was written for speed. A 2-pass color quantization would yield
better quality in 256 color modes, but at the cost of speed.
To have both high speed and high image quality, use hicolor or truecolor
modes. If you don't have a graphics card capable of hicolor/truecolor,
buy one. They're not that expensive anymore.
(To be honest, at first I didn't even plan to support 256 color modes
at all, but later it became obvious that there are still many 256 color
people...)
------------------
Question 11:
~~~~~~~~~~~~
> It takes so long to read a directory from a CD-ROM. What can I do?
Switch 'File info' off using the '*' key before changing to the CD-ROM's
directory. Now QPEG won't examine each file anymore to get its width and
height. If you view images from CD-ROMs very frequently, you should change
QPEG's default setting for 'File info' to off, just edit the respective
line in the QPEG.INI file.
------------------
Question 12:
~~~~~~~~~~~~
> Which configuration file should I use?
Most "experts" know which chipset is used by their graphics card, and
therefore they know which configuration file (*.CFG) to use.
If you don't know that, there are several ways to find it out, one of them
is usually successful:
1. Have a look at the manual of your graphics card, it should mention the
name of the chipset being used by the card. Often the name of the card
ist identical to the name of the chipset, or the chipset's name is part
of the card's name.
2. When the computer is startet (after power up or reset, before the DOS
operating system is loaded) the chipset's name should be displayed on
the screen.
3. Some graphics related programs and hardware test utilities are able to
detect and display the name of the graphics card's chipset.
4. At the DOS prompt, enter "DEBUG". Then (at the DEBUG prompt "-") enter
"dc000:0" to display the beginning of the video BIOS memory area. It
usually contains the name of the graphics chipset. You can type "d"
to view more of the video BIOS.
(Some graphics cards which are fixed part of the main board use a
different location for the BIOS, in this case try "de000:0" instead.)
As soon as you know the name of the chipset, delete the old configuration
file (QPEG.CFG) and copy the new one to QPEG.CFG; then you're finished.
If you can't find a suitable configuration file, please read question 1
and its answer.
------------------
Question 13:
~~~~~~~~~~~~
> VESA - what's that?
First of all, the VESA we are talking about has nothing to do with the
VESA local bus (VLB). You don't need a VLB equipped machine to be able
to use QPEG's VESA configurations.
VESA (Video Electronics Standards Association) is a standardized method to
put graphics on the screen. The advantage is that it's independent from
the VGA graphics card and its chipset, i.e. QPEG's VESA driver works with
all VGA cards which are VESA compatible.
You may be asking if your graphics card is VESA compatible. Unfortunately
not all of them are, otherwise QPEG wouldn't need all those drivers and
configuration files, and the users wouldn't need to worry about configuring
QPEG.
Have a look at your graphics card's manual, it should mention if your card
is VESA compatible. Many modern cards have VESA compatibility built into
their BIOS ROM, such cards work with one of QPEG's VESA configurations.
You can use the VESATEST program (distributed with QPEG) to check if there
is any VESA support.
Most cards which don't have built in VESA are shipped with a driver disk,
containing a so-called VESA TSR (often referred to as VBE, i.e. VESA BIOS
Extension). Simply run that program before starting QPEG to make your
graphics card VESA compatible. Again, use the VESATEST utility to check
for correct VESA support.
If you don't have such a VESA TSR either, you can try to get one. For
example, there are UNIVBE and UNIVESA. They're freeware or shareware
programs, available at most major PD/Shareware sources. They're on many
graphics related CD ROMs, too.
There's one small problem: There are two VESA standards, an old one (1.0
and 1.1) and a new one (1.2). The old one supports only graphics modes
using 16 and 256 colors, the new one additionally supports hicolor (32000
and 65000 colors) and truecolor (16 million colors). So if you have a
graphics card capable of hicolor and/or truecolor and you wish to use
that capabilities, you need to have VESA version 1.2. (The VESATEST utility
displays the VESA version.)
QPEG has three different VESA configurations:
- VESA.CFG supports 16 and 256 color modes. VESA 1.0 is sufficient.
- VESAHI.CFG additionally supports hicolor, requires VESA 1.2.
- VESATRUE.CFG additionally supports Truecolor, requires VESA 1.2.
Many users think that the VESA configuration is a makeshift, and that it's
slow and has other disadvantages. That is not true. It supports everything
that the other configurations support, and it's not noticeable slower.
I'm using VESATRUE.CFG myself, although my ET4000/W32 card has a dedicated
configuration (ET400032.CFG), because my VESA BIOS offers more video modes.
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