How To Become A Co-Inventor
Sometimes it comes down to being in the right place at the right time.
I was standing in the hallways of Building 27, talking with Robin Speed, who’d built what eventually came to be known as DirectShow (Microsoft’s video processing technology), when Gary Sullivan walked up. Gary was Microsoft’s liaison to all things video standard related. Gary is a consummate professional with impeccable political skills and a perennially sunny disposition; but that day, he was a bit crestfallen. We asked him what was wrong.
“Guys, I’m really struggling with this problem: how can you apply two signed 8-bit corrections to an unsigned 8-bit value, and still get full precision?”
We immediately knew what he meant. The full range of a signed 8-bit integer is -128 to 127 (inclusive), so adding two of them together didn’t seem like enough to get you all the way across the full range of an unsigned 8-bit integer (0 to 255).
127+127=254.
“It doesn’t seem like this should be a problem,” Gary said. “After all, we’re applying 16 bits’ worth of correction to just 8 bits’ worth of pixel value! But the correction has to be applied to an unsigned value, and the corrections definitely have to be signed.”
We agreed.
After a minute or two of discussion, we realized that the problem could be solved by baking a little extra information into the expression: just subtract the second 8-bit signed value.
127-(-128)=255.
Problem solved.
I think Robin Speed deserves more credit for the idea than I do, but that’s why he is listed first on the patent application.
Anyway that is how I came to be listed as co-inventor of US Patent 2002/0063792.