Can someone explain something about DV to me? From what I understand it actually reduces dynamic range, doesn’t it? Doesn’t it do the equivalent of turning the volume of a sound system up for quiet bits of a symphony, and down for louder parts, robbing the piece of it’s intended impact?
Lets imagine I am writing Die Hard 6 (or whatever we are up to). My story has John McLean chasing a bomber around New York. Throughout the film the bomber creates larger and larger explosions. Lets say the peak light on these explosions is encoded at 600 nits, 1,000, 1400 and, for the finale, the full 4,000 nits!
Lets also say we have a TV capable of making 1,000 nits, so some tone-mapping is needed. Now, an HDR10 set will have a tone map for the entire film and probably display the explosions something like:
500nits
800nits
975nits
1,000nits
Preserving, as much as possible, the creators intend of escalating explosions throughout the film.
A DV set, though, would probably display them as:
600 nits
1,000nits
1,000nits
1,000nits
As it adjusts the overall level of brightness on a scene-by-scene basis to the capabilities of the set, and tries to display that individual scene as well as possible, even if it leaves no headroom for later parts of the film. This does not follow the creators intent at all.
Another example would be a camera filming the sun rise, with a scene change every 10 minutes….the DV would keep resetting the overall brightness of the scene (making it look as though the sun got dimmer with each set change, as the DV adjusts the tone map for the new minimum/maximum values to fit in with what the screen can do, before ramping back up to the full brightness the TV is capable of), rather than giving it a nice smooth ramp up in brightness (until you hit the maximum the TV can display) over the course of the film, as an HDR10 set would.
I could absolutely understand setting a custom tone map for a film or TV episode, which takes into account the capabilities of the TV it's produced for, but I don't see how doing it scene-by-scene helps preserve the overall drama of the piece.
I also disagree that a TV that misses out some detail on the Pan sun scene is doing something wrong. Doesn’t it make sense for a TV to show the low-mid range brightness of a film as it was intended, and then tone map the bright parts until it runs out of brightness? If we lose detail we lose detail, but I don’t want the brightness range of the whole image compressed to show me bright details. We only had 120nits of range for SDR so even 500 nits of range is relatively big. If something goes beyond the capabilities of my screen I’ll live with not being able to see the detail in it...I'll still be getting a lot more than I would if I watched in SDR.