ANSI SCTE 247-2018 pdf free download – High Dynamic Range (HDR) Video: System Requirements for Cable Phase 1 – Initial Deployment.
6. Introduction to High Dynamic Range Video
6.1. Video System Discussion
As noted in the Background section of this document, the end-to-end nature of video services necessitates that some latitude be afforded to the description of how this SCTE document fits within the scope of other SDO work.
High dynamic range video shall be considered in the context of modern cable systems, in which cable operators deliver a variety of video services (e.g., live linear channels and on-demand content) to a variety of consumer devices (e.g., cable STBs, smart TVs, PCs, tablets and smart phones) over different network infrastructures (e.g., the cable hybrid fiber-coax (HFC) plant, in-home DOCSIS/WiFi IP delivery and external internet connections such as wireless carriers’ 4G networks). In addition, DVR, “cloud DVR” and “start-over viewing” add complexity and technical requirements to the not-so-simple case of live linear channels.
The result is that modern cable systems must support many different, highly complex paths in which content must flow among various subsystems with cable operators’ plant. Moreover, cable operators exist in the middle of an entire end-to-end ecosystem in which many aspects of content production and consumer devices are beyond their control, but which impose certain technology constraints and limitations. In order to develop the requirements contained in this document, SCTE DVS scrutinized both live linear channels and on-demand content delivery on an end-to-end basis – from content production through various stages of delivery all the way to the consumer display. It is clear that the requirements for Next-generation cable systems need to take into account many important complexities and differences from the far simpler situation of purely on-demand delivery of pre-recorded content; and yet next- generation cable systems must provide a competitive viewing experience.
Figure 1 provides a very simplified high-level view of the end-to-end content ecosystem for the case of live linear channels. The Figure is intended to provide a high-level reference for discussing the functionality that is required throughout the content ecosystem; it is not representative of specific systems or architectures, which can vary widely among various content producers, programmers and cable operators. Referring to Figure 1, on the ‘production’ side of content, it is important to understand that there are two categories of linear content creation and distribution – truly “live television” streams, which may include sports, special events, news and other content, and linear streams which are a compilation of pre-recorded content (a traditional linear television channel).
The linear television signals that cable operators deliver to their subscribers comes from many sources, including cable programmers, broadcast network local TV station affiliates and independent local broadcast TV stations, and operator-produced programming such as sports and news. In particular, the production of live television programming has many considerations related to producing content for both next-generation distribution and audiences as well as legacy HD and SD distribution and audiences. Although the topic is outside of SCTE’s scope, some of the many production considerations regarding proper camera shading, lighting, conversion between PQ and HLG HDR systems, the SDR to HDR upconversion and HDR to SDR downconversion needed to intermix HDR and SDR cameras, and graphics generation for both signals are described in ITU-R Report BT.2408-2017 “Operational Practices in HDR Television Production” [31] and the “UltraHD Forum Phase A Guidelines” [32].ANSI SCTE 247 pdf download.