This ridiculous exercise is here to amuse and enlighten those just dipping their toes in the swamp, to the multitude of errors that can and are introduced by downstream "fixes" for so-called "fullrange yuv," which in itself is an oxymoron, if not an extremely common one.
This is RGB Shirley, also called Fullrange (or "PC") Shirley. If there weren't still a lot of analog TVs that would choke on her, everything would be dandy. If you can't see gradation between 0-16 and 235-255, drop back in when your monitor is calibrated correctly. Calibrize is cool, Spyder is amazing in concert with a trained pair of eyes.
This is YUV (or "TV") Shirley, happy and correctly stored at 16-235. She will, by design, play back the same as RGB Shirley above, but represents a compromise because she will play on older TVs correctly, too. We didn't used to see her much in the wild, except when their were first-tier flag errors (more to come on that).
Now meet Clipped Shirley. We see her quite a lot, because most cell phones, DSLRs, and pocket cams shoot "Fullrange YUV," which I said is an oxymoron. It's a sad commentary that many (most?) uninformed consumers actually prefer this mutation, because that's what they're used to seeing, almost everywhere. This first thing an informed viewer will see is a clipped image, with 0-16 and 235-255 completely blocked up, leaving blotches in the hair and facial tones. But 5 billion phones and devices can't be wrong, right?
This is overcorrected Shirley, happens when correct YUV Shirley gets flagged as Incorrect Fullrange Shirley, run through a converter, then gets played back on one of the players that recognizes the flag. This happens a lot actually, because the "converters" that do this assume it's cellphone video, and have no way of knowing if it's already been corrected. Just ran into this again last week.
This is "almost" the worse case. YUV Shirley flagged as Fullrange, run through a converter, flag recognized by player, and the smart kid left the Dynamic Contrast hardware filter on to boot. It actually happens, and the inevitable complaint is that the encoder messed up. The encoder, for those who don't understand by now, is the only thing that WASN'T messed up by operator error. It's doing exactly as it was told!
OK, so smart kid thinks he'll just adjust the contrast and brightness to "fix" it. Let's say he actually gets it back to 0-255 playback levels. Only catch is, he's lost almost 40% of native bit depth (available colors), so it looks kind of like pre-16 bit monitors, or maybe Swiss cheese (note the histogram.) The banding at HD resolution is nothing short of horrible. Is this really what he wanted? How would YOU go about undoing all the misinformation that led up to this? Will this kid work part-time at a ski resort for the rest of his life?
The moral?
Deliver only16-235 YUV, not a kludge, and hope for the best. The rest of the nonsense actually presents a compelling case of the cure being worse than the ailment.
YUV delivery media include .mpg, .mp4, m4v, DVD/BluRay, AVC/h264 x265, and a few nonstandard AVI, but not wmv. Comments invited. Best.
And don't call me Shirley.
