Instruction manual

HDE-3000 - 62 -
UYC files
The uyc file format was developed to optimize the loading speed of the graphics
information into the HDE-3000. A uyc file contains the color information and the
alpha information for each pixel in the image. The color information for each pixel is
stored in YCrCb format (Y = luminance, CrCb = chrominance). The alpha
information consists of an 8 bit value for each pixel. The alpha information controls
the transparency of each pixel independently from the color. An alpha value of zero
means that the pixel will be transparent (you will only see background video for this
pixel). An alpha value of 255 means that the pixel will be opaque (you will only see
the overlaid image for this pixel—no video). Values from 1 to 254 mean that the
pixel will be semi-transparent. For example, a value of 64 will cause the pixel to be
75% video / 25% image, and a value of 128 will cause the pixel to be a 50% video /
50% GI image.
UYC File Positioning Parameters for NTSC
The positioning parameters (xPosition and yPosition) tell the HDE-3000 where to
overlay the uyc file on the TV screen. For NTSC, the TV screen is 720 pixels wide by
525 lines, but 40 lines are used for the VBI (vertical blanking interval), and two lines (line
21 of each field) are used for closed captioning. The HDE-3000 can overlay lines 23 to
263 in field 1 and lines 23-262 in field 2, so the total number of lines that the HDE-3000
can overlay is 481.
The xPosition parameter controls the left/right positioning of the uyc file on the TV
screen. It tells the HDE-3000 where to place the left edge of the uyc file on the TV
screen. Valid values are from 0 to 359. A value of 0 will place the left edge of the uyc file
at the left edge of the TV screen. A value of 159 will place the left edge of the uyc file in
the middle of the TV screen.
The yPosition parameter controls the up/down positioning of the uyc file on the TV
screen. It tells the HDE-3000 where to place the top edge of the uyc file on the TV
screen. The yPosition parameter is the video line number at which to place the top edge
of the uyc file. Valid values are from 23 to 262. A value of 23 will place the top edge of
the uyc file at the top edge of the TV screen. A value of 141 will place the top edge of
the uyc file in the middle of the TV screen.
Full Frame UYC files for NTSC
For NTSC, the full frame uyc file size is 720 X 480. When full frame uyc files are
used, then the xPosition parameter should always be 0 and the yPosition parameter
should always be 23.