DVB UHD-1 covers elements for the improvement of video and audio quality for broadcast TV services.
In addition to UHD (4K) resolution and a wider colour space, these elements include High Dynamic Range (HDR) for increased contrast ratios, High Frame Rate (HFR) for sharper images of moving objects, and Next Generation Audio (NGA) for the support of object- or scene-based audio schemes. The revisions and updates pertain to DVB-DASH, audiovisual coding and bitmap subtitles.
MPEG-DASH revisions
The revision of ETSI TS 103 285, the DVB MPEG-DASH Profile for Transport of DVB Services over IP Based Networks, was approved. It adds the following new features: the provision of live text messages and slideshows for use with Hybrid Digital Radio; support for linking interactive applications to broadcast services delivered by DVB-DASH; HDR; HFR; and NGA.
Also approved were amendments to TS 101 154, the DVB video and audio coding specification. The amended specification contains H.264/AVC and HEVC video conformance points for use with MPEG-DASH. These are aligned with the broadcast codec conformance points, supporting a similar feature set, but take into account the specific requirements of adaptive bitrate delivery over IP-based networks.
UHD subtitles
Lastly, amendments to DVB Subtitling Systems (ETSI EN 300 743) were approved. These add explicit support of subtitling for UHDTV services, as defined in ETSI TS 101 154 and ETSI EN 300 468. The latest revision introduces technical extensions specifically for progressive-scan subtitle object coding and the capability to provide the subtitle CLUT (Colour Look-Up Table) for colour systems other than ITU-R BT.601. The new progressive-scan subtitle object coding allows subtitles to be converted from suitably coded PNG files. The bitmap-based subtitle specification is complemented by TTML-based subtitle specification, draft EN 303 560, which was approved by the SB in July 2017.
Commenting on completing the milestone DVB UHD specifications, Peter MacAvock, DVB Chairman said: “UHD is a key part of many broadcasters’ portfolios. DVB has worked tirelessly to finalise a comprehensive set of specifications for UHD. While work continues, DVB is certain that broadcasters can confidently implement UHD on the basis of its specifications.”
