thornton@ssc-vax.UUCP (Ken Thornton) (10/05/87)
I'm building my own frame buffer and need hardware to do the
RGB to composite conversion.
I've scanned the Motorola, National, and Signetics linear books
and have come up with the LM1886. It accepts 3 bits each of RGB
and can output composite video. The luminance is encoded from the
standard NTSC equation Y = 0.3R + 0.59G + 0.11B (see the National
Linear databook pg. 10-120. The device is called a TV Matrix D/A).
My images, though, are likely to be 4 to 8 bits each for RGB.
My questions are:
1) Do designers of high-end frame buffers typically perform
some compression or dithering on the images before conversion?
2) Do they design custom RGB to composite hardware?
3) Are there higher-end chips that accept more than 3 bits per
primary?
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