Burst Electronics BG-3 - Manual (Page 22)

This example would create a thin strip horizontally across your monitor.
Another example using a max height of 508 would have a max width of 128. 508 is evenly
divisible by 2 and 128 is evenly divisible by 4, also 508 x 128 = 65,024. This example would
create a thin strip vertically down your monitor.
Any size of OSD image can be created as long as the above rules are not violated. For
example, a very small OSD image of 4x2 is valid. 4 is evenly divisible by 4, and 2 is evenly
divisible by 2 and does no t exceed 65,280 pixels.
To create a area of transparency within your OSD image, set the RGB value of the pixels to
255 (R = 255, Green = 255, and Blue = 255). This area will appear white in both Paint and BG-
3/BG-7 interface software, but once installed i nto the hardware, these pixels will appear clear.
The software also has the ability to change the Transparency Value. The number displayed in
this field converts this RGB value to transparent. For example, if you change this value to 128,
then all pixels with RGB = 128 (Red = 128, Green = 128 and Blue = 128) will become
transparent. This allows you to make any RGB value clear. When creating an area of black, we
recommend using an RGB value of no less than RGB = 25. A value of RGB = 25 will create
black at 7.5IRE. A value of RGB = 0 will create black at 0IRE (which can be troublesome for
NTSC). If creating an OSD image in PAL, then RGB = 0 is just fine. When creating an area of
white, a value of RGB = 254 (note RGB = 255 by default is transparent) will create white at
approximately 85IRE.
Included with the BG-3/BG-7 software are several example OSD images to help you in creating
an OSD image that this product can accept. These OSD images are located on the CDROM
under the folder named IMAGES (and also on your hard drive at \Program Files\Burst\BG7
\Images). These images are;
128x508.bmp
256x254.bmp
256x254-w-Transparent-Box.bmp
508x128.bmp
508x128-w-Transparent-Box.bmp
720x90.bmp
BURST-logo-BG7 -24C.bmp
White-256x254.bmp
It is also recommended that any horizontal line be at least 2 pixels tall. This is due to the fact
that one pixel in height will write to only one line of video (example Field 1 line 120 has data,
but field 2 line 121 does not). This can cause a one pixel horizontal line to appear jumpy. The
most simple way to avoid this is to draw your horizontal line with 2 pixels high (so both field 1
and field 2 have data).
Loading OSD Images
Loading an OSD image into the BG-3/BG-7 is accomplished by the following steps (this
assumes that you have connected the hardware to the computer and that you have established
communication to the hardware);
BG-3 and BG-7 Test Pattern Generator 22