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| A-/D-Converter problem: values range 0 .255 vs. 16. .235
Question of Gubbel:
November 2010
Hello and happy first Advent!
Again I have a special little problems. Although I've already searched the sore fingers, I have found nothing that can help me ...
In a standardized analog signal is 300mV and 1000mV black white. But now synonymous values can top (; super-white) or down (; super-black) value.
In the digital YUV component in the y-value is 16 black and 235 white. With the proc amp in the capture card I can adjust these values change.
Now I have 2 cards:
- Pinnacle PCTV Stereo (; PCI)
- Pinnacle USB -500 (; USB)
In VirtualDub, there is a Histogram function for the Y-component that displays all values of 0 .255 and everything is above 235 or below 16 in red. Now I have found out so that the PCTV may disqualify up to 255 and the USB only -500 to 235 ..
At the bottom, both clipping even at 16, including nothing more.
Now I would, however, the record head-and foot room happy with, but how?
If I play the recording later, or open in VDub, so everything is displayed in RGB, since Y16 and Y235 to RGB0 to RGB 255, so I do not see any difference ...
Only if I stay in the YUV color space and create a DVD, then comes s.DVD Player at about 300mV and 1000mV nothing more, even though values could be there ...
How should I handle the s.besten?
MfG
Alex
Reply WoWu:
Alex
I'm not sure if I understood right, what you want, but if you go from a predetermined color space, colors are discolored.
Unlike RGB, the works of 0-255, runs the Y'CrCb (YUV) color channel of the middle of the values at the sides.
Thus, when values below the intended range of values are created, dark colors to color green and if the values are above the permitted range of values, the bright colors of pink color. Ranges should therefore always be limited by the NLE in the approved area otherwise held a spreading of the color space. (You get so no more colors)!
Areas below 16 and above are of 235, for xvYCC. This requires an appropriate control signal to be carried s.den Monitor the results that the range is ever shown.
At best you use the words provided color space.
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