DVB Updates UHD Specifications for IP Networks

The Digital Video Broadcast (DVB) has added final revisions to its first DVB UHD-1 specifications for Ultra HD covering transport of UHD services over IP networks. This comes just over a year after the DVB Project approved the underlying standards in October 2016 as UHD-1 Phase 2 (TS 101 154) for broadcast networks.

The base standard approved last year provides the foundation for deployment of all the components now associated with UHD, including many that have yet to be formally agreed, never mind deployed in commercial services. These include 4K resolution, Wide Color Gamut (WCG), High Dynamic Range (HDR) for increased contrast ratios, Higher Frame Rates (HFR) for sharper images of moving objects, and Next Generation Audio (NGA) for the support of object or scene-based audio schemes.

The IP support just added also enables some specific services, including provision of live text messages and slideshows for use with Hybrid Digital Radio, as well as support for linking interactive applications to broadcast services delivered by DVB-DASH. At the same time the DVB has also approved amendments to the standard for video and audio coding. These bring conformance points for use with MPEG DASH, aligning these with broadcast while taking account of specific requirements for adaptive bitrate delivery over IP-based networks.

The final part of the new amendments adds explicit support of subtitling for UHDTV services, as defined in ETSI TS 101 154 and ETSI EN 300 468, under the heading DVB Subtitling Systems (ETSI EN 300 743). These are technical extensions specifically for progressive-scan subtitle object coding, allowing subtitles to be converted from suitably coded PNG files.

These amendments complete this current first round of DVB UHD specifications, although as Peter MacAvock, DVB Chairman, pointed out, there is work still to be done on detailed implementations. MacAvock insisted though that broadcasters can now safely get cracking with UHD deployments. “While work continues, DVB is certain that broadcasters can confidently implement UHD on the basis of its specifications, “said MacAvock.

The amendments will still leave some broadcasters and operators confused over the exact status of these various standards, which are at different stages of evolution with a variety of bodies involved. The DVB has grown out of its European roots to become a body designing standards for delivery of TV and associated data services around the world. However, the standards are implemented under the banner of ETSI, the European Telecommunications Standards Institute, which again has reached out to the world with associate members in every permanently inhabited continent and collaborates strongly with its US counterpart, the American National Standards Institute (ANSI).

 Broadcasters can now confidently implement UHD on the basis of DVB specifications, according to Peter MacAvock, DVB Chairman.

Broadcasters can now confidently implement UHD on the basis of DVB specifications, according to Peter MacAvock, DVB Chairman.

Confusion has resulted from the emergence of not one but two bodies dedicated to UHD, but neither of which actually defines the standards. They do however publish sets of recommendations comprising standards set by others, including the DVB.

The first body, the UHD Alliance, is concerned with the two ends of the video delivery chain, the in-home viewing experience provided by TV sets or other CPE and the creation of content in the first place, whether from camera or computer generation.

Then the second body, the Ultra HD Forum, deals with all the infrastructure in between camera and viewing device, with a strong focus on interoperability but also backwards compatibility, which brings it into overlap with the UHD Alliance. Indeed, there are signs that the two bodies will converge in 2018, according to the weekly analysis site Faultline Online Reporter published by Rethink Technology Research.

The Ultra HD Forum has conducted a survey asking pay TV operators and broadcasters for views about the body’s second round set of UHD specifications known as phase B. Phase A was the Ultra HD Forum’s first tranche of standards covering technologies already available commercially in 2016, including 4K 2160p resolution, the advanced BT.2020 color space and first versions of HDR, PQ and HLG, but frame rates only up to 60 fps and no NGA (Next Generation Audio).

Phase B embraces technologies that were on the drawing board early in 2016 but not yet available commercially or even in trials. The Ultra HD Forum now considers phase B technologies to be those likely to become available and deployed between two and five years from now, this being the period covered by its survey.

As Faultline pointed out, phase B is most concerned with HFR and NGA. So, while these are supposedly included in the DVB’s first round of standards already on the table, the Ultra HD Forum views them as not yet available. The devil here lies in the details in that while the DVB has provided a guaranteed framework to give broadcasters the confidence to start developing UHD services now, the exact specifications remain to be defined. For example, HFR could mean going up to either 50 fps or 60 fps at the lower end, but 100 fps or even 120 fps to deliver a better experience still for fast moving action.

There is also a lot of debate over implementation of NGA, as was clear from the recent Next Generation Audio Summit organized by SVG Europe in conjunction with Dolby. This summit gave air to ongoing discussions over adoption of immersive and object-based audio. The message for broadcasters and operators is that it is time to get going with UHD tests and trials, especially of the earlier technologies listed under the Ultra HD Forum’s phase A, but too soon to deploy HFR or NGA at any scale.

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