jmac698
6th August 2006, 17:44
I'm trying to undo upconversion. I measured colorbars, the white box is supposed to be 1/4 active picture height high.
signal height height*4
SD 120 480
HD 270 1080
And 270/120=2.25 so it's stretched 2.25 vertically.
Now for horizontally. The bars should be 1/7 active line width, all seven measured about 1413. Since this represents about 711 pixels (according to capture FAQ), the total width should be about 1431. Yet, I see some images out to 1440. If I assume 720->1440, the bars occupy 706.5 active pixels.
To be sure, if width was expanded 2.25 we get 1620. That width is definitely not displayed, unless it gets cropped. If it were cropped, you get 1440/1620*720=640. But it can't be cropped, or the colorbars would be way too wide. What's going on here?
signal height height*4
SD 120 480
HD 270 1080
And 270/120=2.25 so it's stretched 2.25 vertically.
Now for horizontally. The bars should be 1/7 active line width, all seven measured about 1413. Since this represents about 711 pixels (according to capture FAQ), the total width should be about 1431. Yet, I see some images out to 1440. If I assume 720->1440, the bars occupy 706.5 active pixels.
To be sure, if width was expanded 2.25 we get 1620. That width is definitely not displayed, unless it gets cropped. If it were cropped, you get 1440/1620*720=640. But it can't be cropped, or the colorbars would be way too wide. What's going on here?