[noggin]

I didn't say RGB 16-235 wasn't a standard. I said it wasn't used by Consumer Electronics (CE) equipment. CE devices send out YCrCb (16-235) for HDMI video. If they support anything else it's not the default and you have to go tinkering around in menus to change it.

My experience is very different from yours. All the HDTV's I've used treat RGB 0-255 as the normal case, and RGB 16-235 as the odd case (if they even support RGB 16-235). This is because CE devices send out YCrCb and when the TVs see a RGB signal they assume they are being fed by a computer which sends out 0-255. Further, digital displays natively are almost all RGB. Internally, after all their processing, they send RGB 0-255 to the DACs/TCONs/drivers (unless they're >8bit displays). Expanding RGB 16-235 to RGB 0-255 somewhere downstream of the color space conversion is a great way to get banding/posterization. Converting YCrCb (16-235) directly to RGB 0-255 gives better visual results than converting YCrCb (16-235) to RGB 16-235 and having your display turn it into RGB 0-255 due to the floating point math used in the color space conversion and the way the floating point values can be mapped to any target level range or bit depth. You get no such luxury converting RGB 16-235 to RGB 0-255.

Since the Chromebox is a computer and OpenELEC does not default to YCrCb playing back videos in their native color space and chroma format I stand by my contention that it should output RGB 0-255 by default for the best video quality, not RGB 16-235.

Sorry - I'm afraid my experience doesn't tally with that. My Sony HDTV and my Panasonic HDTV both default to 16-235 RGB levelspace.

This is the expected behaviour for HDMI as per the HDMI 1.3 spec : http://www.microprocessor.org/HDMISpecification13a.pdf

Section 6.6 of this is :
"6.6 Video Quantization Ranges
Black and white levels for video components shall be either “Full Range” or “Limited Range.” YCBCR components shall always be Limited Range while RGB components may be either Full Range or Limited Range. While using RGB, Limited Range shall be used for all video formats defined in CEA-861-D, with the exception of VGA (640x480) format, which requires Full Range."

CEA-861-D defines the standard TV and HDTV HDMI specs used for TV (480i/p, 576i/p, 720p, 1080i/p, and now 2160p at standard HDTV rates) so the HDMI spec states that 16-235 RGB Limited values should be used for TV resolutions. Full 0-255 levels should be the default for non-TV resolutions and the not-quite-TV 640x480p square pixel 4:3 res.

TV black levels, whether in SD or HD or 4K, and whether YCrCb or RGB are 16-235 (or 10 bit equivalents) HDMI follows broadcast specs for broadcast resolutions. It follows the PC/DVI RGB specs for PC resolutions. Whether all consumer gear follows the HDMI spec is another matter of course. YMMV.