Calculator for video timings v. 1.6

Copyright Tomi Engdahl 1998-2004

NOTE1: You need at least Netscape 2.0 or IE3 browser with JavaScipt/Jscript turned to to use this form. This calculator version has been tested using Netscape 4.

NOTE2: This calculator application is in development stage and there is no guarantee that the results you get from this from are correct. Use this at your own risk. If you find errors in this page please e-mail me with a good description what is wrong.

Select the screen mode timings:

Or give Xfree86 modeline to import:

Graphics card parameters to fill and modify

General parameters

Pixel clock frequency MHz

Interlace

Horizontal timing parameters

Resolution pixels
Front porch pixels
Sync pulse pixels, polarity (0=NEGATIVE,1=POSITIVE)
Back porch pixels

Vertical timing parameters

Resolution lines
Front porch lines
Sync pulse lines, polarity (0=NEGATIVE,1=POSITIVE)
Back porch lines

Move picture:

This page lists the most commonly used resolutions and refresh rates that you can modify. You can modify all the parameters you want. The you can use any combination of H and V resolution (ok, number of pixels) and refresh rate that are supported by your operating system, graphics card and your monitor. Windows is pretty much limited on what resolutions it can use, but with X you can pratcially use almost any any combination of H and V resolution (ok, number of pixels) and the limit is the card (clock and RAM) and the monitor capabilities.

Note 1: Actual vertical and horizontal refresh rated depend on the screen resolution, vidoe clock rate and some other numbers (porch and sync pulses).

Note 2: The horizontal timing parameters must be normally to be multiple of 8 because this is the resolution which stadard VGA cards operate in those timings and same applies to most of SVGA cards also.

Note 3: Screen mode settings do not set the sync signal polarity because the needed sync signal polarity depends on the monitor and screen mode used. If you do not know what polarity is needed try first to check both negative. Sync signal polarity settings do not affect the timing calculations. Sync signal polarities affect only to the generated configuration files.

Note 4: Moving picture the picture to the extreme positions may result unstable picture on the monitor.

Note 5: The screen mode settings are general settings usually targeted for 8 bpp (256 colors) modes. On some higher color modes some graphics cards seem to have some limitations what horizontal resolution settings can be (a multiple of 32 pixels in some cards). This might cause that all settings might not work with all card in all modes. Because of large variety of graphics cards and operating systems, not all combinations of things could have been tested. If something does not work for you, then try some other settings or try to modify the mode to suit better to your card (if you know what to correct).

Note 6: In interlaced modes the vertical sync timing parameters are per interlaced field. Interlace draws only half of the screen each refresh, doubling the effective refresh rate. Interlaced modes are well known for their high flicker, but a 60Hz interlaced mode looks much better than a 30Hz non-interlaced mode.

Note 7: Horizontal Sync Time typically varies form 3.5 to 4.0 microseconds in normal PC monitor applications. Vertical Sync Time usually varies from 50 to 300 microseconds.

Press when you want to get the results.


Calculated results

Numerical results

Horizontal sync frequency is kHz and vertical sync frequency is Hz. Field rate is Hz.

Horizontal sync pulse length is microseconds and vertical sync pulse length is microseconds.

Horizontal total is pixels and vertical total lines.

If you want to test other values then fill in new values and press calculate again.

Configuration files

NOTE: The following configuration files are calculated from the data above. There no guaantee that the calculated configuration files work on your system. Use the configuration files at your own risk. In some unfortunate cases it is possible that you damage your monitor or mess up your graphics card driver settings.

Xfree86 modeline:

Matrox Windows driver custom monitor settings:

Windows95 monitor.inf file modeline:
Note: Windows monitor .INF file contains only the screen refresh rate and sync polarity information. It does not contain screen position information.


Tomi Engdahl <>

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