Samsung demonstrate dynamic metadata at CES 2017
Although HDR 10 currently remains the dominant form of High Dynamic Range, Dolby Vision has gained considerable support at CES 2017.Dolby's proprietary version of HDR is now included on TVs from LG, Sony, Philips and TCL, whilst LG, Philips and Oppo offer Ultra HD Blu-ray players that support the format. Dolby Vision is already used by streaming services like Netflix and Amazon, whilst Warner Bros., Lionsgate and Universal announced at CES that they will release Ultra HD Blu-ray discs encoded with Dolby Vision. Part of the appeal of the format is that it offers a closed ecosystem that guarantees a consistent performance regardless of the capabilities of the Dolby Vision display. However another appealing factor is that Dolby use dynamic metadata.
What is dynamic metadata? Well put simply it means that when grading an HDR image the content is encoded on a scene-by-scene or even frame-by-frame basis if necessary. There's no need to take the frame-by-frame approach during an entire scene but particularly when a scene changes to another one, there's the option to encode that scene change on a frame-by-frame basis. Until now HDR 10 content has been delivered using static meta data, which means the content is encoded with a maximum and minimum brightness and an average brightness level. The use of dynamic metadata means that during scenes and between different scenes the brightness can be encoded to deliver the best possible experience in terms of tone-mapping.
Although Dolby Vision was always intended to use dynamic metadata, there is also the option to add it to the HDR 10 open source format. The SMPTE 2094-40 standard covers the addition of dynamic metadata to HDR 10 and Samsung have been a major supporter of expanding the capabilities of the open source and free version of HDR, rather than giving over control to Dolby and obviously paying them any royalties. Samsung are currently trying to generate industry support for their approach, which doesn't actually have an official name yet, although in the demo Samsung used the term 'HDR 10+'. Samsung were showing scenes from Pan in HDR 10 with dynamic metadata on their new Q9 and MU8000 TVs, and without dynamic metadata on the KU7000.
The images in HDR 10 with dynamic metadata were certainly more detailed in the highlights when compared to the HDR 10 footage on the KU7000. However it's worth remembering that where dynamic metadata really adds value is in terms of the tone-mapping, so the better the TV the less important the dynamic metadata. The Q9 can deliver more than 1,000 nits accurately and over 100% of DCI-P3, so it could deliver a detailed and accurate picture even without dynamic metadata. Where dynamic metadata really adds value is on TVs that can't deliver the full peak brightness or colour gamut of the content, this is where the tone mapping is more important.
At present Samsung was merely demonstrating that dynamic metadata can be added to HDR 10 and that their TVs are capable of supporting the technology. They still need to build industry support and to deliver dynamic metadata over HDMI will require HDMI 2.1, the final version of which was announced at CES. However the good news is that the TV manufacturers should be able to upgrade the HDMI 2.0a connections on their TVs to HDMI 2.1 if they so wish. It's still early days and how much support there will be for HDR 10 with dynamic metadata will largely depend on how successful Dolby are in promoting their version of HDR
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