flaXen Image Overlay Tool for VirtualDub

flaXen Image Overlay Filter for VirtualDub
Help File - Covers fxOvl v1.0
Last revision: 26-Jul-00
(c) 2000 Dan Flower (flaXen / X-Bios)

Index

Disclaimer	Legal disclaimer -- It's not my fault!
Introduction	An introduction to fxVHS
Contact Info	My Contact info (email & web page)
Parameters	Definitions for all fxVHS Parameters

Disclaimer

This software is distributed free of charge and is therefore provided "as is" without warranty of any kind, either expressed or implied, including but not limited to, the implied warranty of Merchantability or Fitness For a Particular Purpose. Under no conditions does the Author take responsibility for the results of using this software, direct or indirect, including but not limited to, Damage to Other Software or Hardware Components or Data of Any Type.

That being said, I'm fairly certain this filter won't blow your computer up, but that's what the disclaimer is there for. ;)

Introduction

This filter (hereafter fxOvl) will let you overlay a Targa image on top of your video anywhere you want with several effects. This is good for adding titles, banners, etc.

Contact Info

Want to email me? You can do that! My email address is: x_bios@hotmail.com
Homepage?! I don't need no stink'n homepage! Wait! Ya I do: http://flaxen.dynip.com/vdf

On my VirtualDub filter homepage, you can find example video clips, other video filters of mine, and maybe even the number "4"...

Definition of fxOvl Parameters

Source TGA
fxOvl uses Targa (TGA) files for input. The Targa file you specify must be uncompressed and either 24- or 32-bit color depth. Make sure to check the art program's options prior to, or when, saving to match these criteria.

Method
This specifies the method in which fxOvl will overlay the Targa. You have 6 choises:

Copy This simply copies the Targa on top of the image without any mixing or blending.

Average This takes the average color of the Targa and the image and blends them 50/50.

Additive This takes the sum of the color of the Targa and the image and shows the result.

Subtractive This takes the difference of the color of the Targa and the image and shows the result.

Mask AND This is a boolean AND used for masking.

Mask OR This is a boolean OR used for overlaying on a masked area.

Intensity
This is a scale from 0 to 200 for the intensity of the Targa. Lower values are darker and higher values are brighter. The value 100 is 100% brightness which doesn't affect the Targa at all.

Show for ... seconds
While this is set to zero, the Targa will be displayed forever. If you want the Targa to stop showing after a number of seconds, then this option is for you. The limit is a maximum of 32,000 seconds.

Tips on Tuning Your Settings

This section will help you adjust fxOvl settings for the best results.

The Copy and Average methods are pretty self-explanitory. They are also very fast and could be used for most situations.

The Additive method can sometimes make the logo appear too bright. Lower the intensity control to 50 (for example) for better results. Since the Additive method adds the Targa to the image, black colors won't appear, however, this method produces a good translucent effect.

The Subtractive method is exactly the same as the Additive method except that it subtracts instead. Lower the intensity when using this method to help make the Targa less dark. The Subtractive method can be used to reverse the effect of the Additive method to remove a logo, but takes some work.

The Mask AND and OR methods require you to run the filter twice for proper usage. These methods allow you to overlay a transparent (not translucent) Targa by using a mask in conjunction with the actual picture. The first step is to make a mask. A mask should be the same resolution as the logo Targa, except that the only colors used are pure black and pure white. IT IS IMPORTANT TO USE PURE INTENSITIES or the boolean mask will fail. The mask should have pure white in areas that you want to be transparent and black in areas where you want the logo to show. After applying the Mask AND method with a proper mask, there area on the screen where you set the mask to black will also be black. Areas in the mask that are white will not be modified. The next step is to use the Mask OR method to apply the logo with a second fxOvl filter. The Mask OR method is exactly the same at this point as the Additive method, except that it's faster. Once both the Mask AND and Mask OR filters are applied, the logo should be visible on the screen.

One twist to the Masking methods is to use a Additive method instead of the Mask OR method when you want SOME of the Targa to be added and the rest to be masked. For example, some text with glowing edges. You'd simply add a mask of the text without the glow and add an overlay using the Mask AND method. Then you'd add your Targa of the text with the glow and use the Additive method. POOF! Instant odd effect.