The centrepiece at Hubtricity is the Converged Command Cockpit, where StarHub can monitor how its fixed, mobile and pay-TV networks are performing.
By Chong Siew Loong, CTO of StarHub
In the face of increased competition from over-the-top (OTT) service providers, broadcast operators have to constantly innovate to provide a richer viewing experience with more personalisation and deeper customer engagement. Typically, broadcast operators would leverage SDI technology at the TV headend to process the broadcast channels before distribution to set-top boxes and other devices.
With the development of video-over-IP standards and solutions, operators can now adopt IP technology at the TV headend to reap the benefits of flexible routing, scalability and agility. This also lowers the cost of ownership with commercial-off-the-shelf (COTS) IT and IP infrastructure, which helps to ensure a better return on investment (ROI).
At StarHub, we have been embracing IP as part of our TV headend architecture and delivery platform. Our journey began in 2003, when we launched our digital TV channels.
Six years later, we implemented Transport Stream over IP (TSoIP) after the encoder and playout servers, and leveraged COTS IP switches for redundancy. In this configuration, all channels were routed to the baseband system to support master control functions, SDI ad-insertion and video switching.
2017 has been a landmark year as we moved our TV headend into our latest facility, Hubtricity. The centrepiece at Hubtricity is the Converged Command Cockpit, where we can monitor how our fixed, mobile and pay-TV networks are performing. We implemented an IPTV headend architecture (bypassing the traditional SDI baseband system) and delivering Transport Stream over IP after the IRDs (integrated receiver decoders) for turnaround linear channels. With this design, our master control graphic functions are operated directly from the encoders through the control switching software. We also have the capability to monitor the IP streams at the IP and MPEG video layers so that the team can detect any video or audio loss at all times.
When we were planning our new TV headend in 2015, uncompressed video-over-IP technology was still evolving with multiple proprietary solutions in the market. This presented us with interoperability challenges. Hence, we did not implement uncompressed video-over-IP at the time.
Instead, we decided to adopt the strategy to build an IP-enabled headend platform with the capability to deliver the channels directly to the compression system, bypassing the traditional SDI baseband routers. We conducted extensive proofs-of-concept for this IP-enabled headend. Through the testing and assessment, we identified several key success factors for an IP-enabled TV headend. The key design considerations are video quality, latency, seamless IP video switching, IP ad-insertion, video formats conversion, master control functions, stability of redundancy design and skillset change.
The following key considerations shaped our IP deployment at Hubtricity:
• Graphics functions on IP — One of the biggest challenges in adopting a transport over IP solution is how to enable graphics capabilities on the IP platform instead of the traditional SDI baseband system. Fortunately, as the technology matures, an increasing number of compression manufacturers can incorporate the graphic and channel branding capabilities, such as crawlers, dynamic text, station logos, and multiple layer graphics in the encoder.
• Closed and open captioning — One of the advantages of going to IP is the easy implementation of closed captioning. However, pay-TV operators may face constraints in supporting the different formats of closed captioning from the various content providers. As such, open captioning is still required and the responsibility of the subtitle burn-in function needs to be supported by the compression system.
• Ad-insertion on IP — Most Asian pay-TV operators implement ad-insertion in the traditional SDI baseband system. Moving towards IP, it becomes more cost-effective to implement the MPEG splicing on the IP domain. On the other hand, compression vendors are also incorporating the ad-insertion capability in the encoders. This provides the option to deliver the channel with ad-insertion over IP.
• End-to-end control and monitoring — As most broadcasters have a hybrid SDI/IP system, it is essential that the control and monitoring system is able to support both SDI and IP. This covers important functions such as graphics control, redundancy switching, status monitoring, error correlations and performance reporting.
• Format conversion — Two considerations to go IP are how to address the conversion from NTSC to PAL, as well as from a 1080i60 to 1080i50 frame rate. Currently, conversion still has to be done at the uncompressed video level. Hence, we are using traditional SDI for such channels.
• Video switching for TS over IP — Many compression vendors demonstrate the capability of switching the TS over IP. However, the switching is sometimes not seamless and the control system of switching is not as comprehensive as the traditional A/V routing system. For channels which require real-time video source switching, we maintain the channels at SDI.
• SDI over IP — With the increasing need to support 4K/Ultra HD (UHD) content, it is anticipated that the latest models of production equipment will support SDI over IP and an increasing number of production facilities will be selecting the COTS IP networking approach. However, legacy SDI routers and new Ethernet/IP networks will coexist for a number of years during the migration to a COTS switch infrastructure. During the transition, it is important to carefully select the scalable IP-based equipment, ensure a reliable IP network design, and have a flexible control system to manage the migration.
Today, we have built an IP backbone to connect the channels from IRDs to the encoder farm while bypassing the SDI baseband router. This design has reduced the infrastructure cost and reduced the amount of coaxial cabling. It is also flexible and allows us to reap the benefits of ease in configuration, IP routing from any source to any destination (without many input and output interfaces) and cabling in a traditional SDI architecture.
As part of the IP headend transformation, we trained our broadcast engineers and operators on the new IP video workflow and seamlessly migrated all the channels from our old headend to Hubtricity in 2017.
Transforming towards IP gives us the flexibility to expand our capacity to support future 4K/UHD channels, which are bandwidth-intensive. In everything we do, our priority is to deliver a world-class viewing experience and as the technology matures, we will enhance our TV headend to go full IP to meet the future entertainment needs of our customers.