How to USE iphone16 pro to capture HDR dolby_vision and use videotoolbox to encode with dolby_vision metadata in bitstream! I know apple ios system can achieve this target,but I want to get source code how to do that ?

context:Explore low-latency video encoding with VideoToolbox https://developer.apple.com/videos/play/wwdc2021/10158/ I see above post said HEVC VideoToolbox can support SVC, temporal layering of streams in low-latency mode with all P frames. my question is that Does HEVC VideoToolbox support temporal layering of streams with B-frames ?? thanks

Does videotoolbox hevc encoder on iphone16 pro encode with 10bit hdr vui info in bitstream ? I want to encode 4k 10bit hdr bitstream with vui info use hevc videotoolbox .but I don't know how to encode vui info in bitstream ? please give me some sample code ?