Originally Posted by P40L0
Yeah, and all DV contents are produced and mastered at High Dynamic Range (HDR) + Dolby Dynamic Tone Mapping @ 12-bit Color Depth.
Displaying them at 8-bit, even if in FullRGB, is just a downconversion in SDR.
I think you guys are completely missing everything aaronwt is saying. He is NOT saying that DV is displayed at 8bit. He is NOT saying that DV is mastered at 8bit. He is saying that DV has the capability to be sent to the display wrapped in an 8bit stream. That means the full 12bit DV is chopped up into 8bit packets, transmitted, then reassembled at the TV into 12bit before it is sent to the screen to be displayed. No downconversion involved, full fidelity preserved.
Spending a few minutes researching found this:
"Dolby Vision doesn’t require new codecs—it can be delivered with industry-standard
HEVC and AVC codecs. The full Dolby Vision signal can be encoded, with pre-processing,
into either a single HEVC Main-10 stream or into two AVC or HEVC layers with lower bit
depth, plus metadata, making it well-suited to a wide range of televisions, personal
computers, and mobile devices. The client uses the data to reconstruct and play back
the full signal, using existing video decoders"
Dolby says above that the full Dolby Vision stream can be encoded into lower bit depth streams and then reconstructed into the full signal. 8bit would qualify as lower bit depth. To get more technical than the generalized statement above, we can look here:
See Section 2.1:
Dolby Vision bitstream Representative Dolby Vision BL/EL codec
profile ID bitstream profile string
4 dvhe.04 10-bit HEVC
5 dvhe.05 10-bit HEVC
7 dvhe.07 10-bit HEVC
8 dvhe.08 10-bit HEVC
9 dvav.09 8-bit AVC
This seems to indicate that profile 9, dvav.09 is Dolby Vision in an 8-bit container, as aaronwt keeps saying. If we look at Roku device capability, here:
under Supported video codecs, it shows Dolby Vision: dvav.09 and Dolby Vision: dvhe.05. This seems to indicate that the Rokus that support DV handle profile 9 and profile 5. This means DV through an 8-bit container and DV through a 10-bit container.
Unless I'm completely misunderstanding things, Dolbys technical papers support what aaronwt is saying.