Hmm ... faldt lige over en sandsynlig forklaring på hvorfor DV virker anderledes og 'mørkere' fra HDMI kilder.
"Dolby Vision definitely too dull on Sony OLED"
https://www.reddit.com/r/appletv/commen ... h=3b53186d
"What Picture Mode is your Sony using for the formats you're comparing? Sony's 2018 Dolby Vision implementation is a little funky…as others have mentioned, it uses Dolby Vision Low Latency for HDMI sources, which means that more of the Dolby Vision processing happens on the source device. It also limits Dolby Vision to one Picture Mode (I believe it's something along the lines of "Cinema Dark") and doesn't let you adjust anything.
HDR10, on the other hand, has multiple Picture Modes, some of which can (and will) be brighter (or less "dull") than the Dolby Vision mode. They're certainly punchier, but might not necessarily be more accurate.
So you have two options:
Let the Apple TV send the Sony Dolby Vision, and trust that the dynamic metadata and color calibration make for a more accurate (but potentially less punchy) picture. Or:
Set the Apple TV to output HDR10 instead. Apple TV will internally convert Dolby Vision source to HDR10…you'll preserve the high dynamic range and high-bit color, but you'll lose the benefit of dynamic metadata (which can change tone mapping from scene to scene, fully utilizing your panel's range).
With a regular Dolby Vision implementation (like LG's), I would recommend #1 without reservation…but the way Dolby Vision Low Latency works, there's an asterisk: Dolby Vision's greatest advantage is that it can dynamically map content to the capabilities of a given panel, and that's limited when some of the processing has to happen on the source device (if the TV is doing the processing itself, it has inside knowledge about its own capabilities that HDMI devices aren't privy to). This is why Dolby Vision looks different on the A8F's internal apps, and why the Apple TV can't do anything to fix it. Ironically, this is also the limitation of Apple TV's Dolby Vision-to-HDR10 conversion…it just doesn't have access to the same information that the TV has, and needs to make assumptions.
TL;DR: The Sony A8F's support for Dolby Vision from HDMI devices is limited, and rendered to a single Picture Mode. If that mode fits your environment, Dolby Vision is still better overall. If you need to overcome a bright room or similar, you'll have to run in HDR10 and adjust the TV as necessary…but you'll lose what remains of Dolby Vision dynamic metadata.