Comment Re:A little confused at the demo (Score 1) 34
Sort of.
Yes, SDR black levels are technically the same, but they tend to be washed out in a lot of productions, especially with brighter images. This is because a lot of video (yes, even high-budget stuff) isn't shot to full spec. Laziness, lack of skill, lack of time, or sometimes just a director going for a certain look.
Shadows in SDR tend to be shot a little "hotter" because of dynamic range issues, though, so you end up with "blacks" that are closer to 10% (or much more) grays in many situations. Most phone-camera videos tend to have problems of this sort (mostly because the scene they're shooting isn't lit that well).
A good SDR-to-HDR conversion process often does some fiddling with shadows to make the blacker parts actually black while recovering some details.