2014-07-10, 00:31
i'd been following the haswell nuc thread for a while before finding out 2955u in the chromebox was a haswell chip and getting that instead. lmyllari did a lot of testing and bug squashing and i believe the same information should apply. that being:
so for my vt50 setting the range to full with the autostart script and then using the 16-235 setting within xbmc gives proper black and colors.
avsforum has a good set of calibration media you can use within xbmc here:
http://www.avsforum.com/forum/139-displa...ation.html
(2013-12-05, 02:17)lmyllari Wrote: The banding comes from expanding luma from 16-235 to 0-255. This is done for typical PC monitors, which expect a full range signal. New Intel linux drivers by default give TVs a limited range signal, taking the expanded 0-255 and scaling it to 16-235. This does not eliminate the banding that was created by the original expansion, and original information below 16 and above 235 was already lost in that same step. (Why do they do it? It's the right thing according to the standards, and some TVs don't like full range -> crushed blacks.)
If the player software (xbmc in this case) decodes to 16-235 (meaning "don't change luminance, keep black at 16 and white at 235"), the video card outputs full range 0-255 (meaning "don't scale the levels, just output what you're given"), and display is set to limited range input (meaning "16 is black, 235 white"), we eliminate the banding in greyscale ramp (because the range is not scaled at any point) and keep blacker-than-black (luma values under 16) and white-than-white (luma values above 235).
If your plasma defaults to limited range RGB (and doesn't listen to the infoframes in the HDMI stream) or you can set limited range manually, you don't need anything special. Just set your player software to 16-235 (which you can now do with Gotham and software decoding) and make sure the video card doesn't change the signal (the xrandr broadcast range "Full" setting mentioned a lot in this thread). In my case, the monitor obeys the infoframes (and there are other devices connected to the same input preventing a manual setting), so I need a patch to switch it to limited range without altering the video signal.
so for my vt50 setting the range to full with the autostart script and then using the 16-235 setting within xbmc gives proper black and colors.
avsforum has a good set of calibration media you can use within xbmc here:
http://www.avsforum.com/forum/139-displa...ation.html
