Strengthening OTT and linear streaming services with SDV
Elemental Technologies on unifying traditional and multiscreen workflows
In this white paper, Keith Wymbs, chief marketing officer for Elemental, discusses the unifying of traditional and multiscreen workflows.
Most linear television operations today include legacy video processing equipment dedicated to specific tasks such as encoding, splicing and multiplexing. As exciting new OTT and VOD services offered by traditional DTH providers gain popularity, video providers are finding that legacy hardware-based video processing equipment cannot keep pace.
Support for content distribution across most traditional pay TV networks requires advanced compression and statistical multiplexing methodologies. Since QAM bandwidth for delivering these channels is fixed, one approach to allocating bandwidth is to simply divide the total available bandwidth by the number of sub-channels and then evenly allocate constant bitrate (CBR) encoding levels. However, this static allocation method is extremely inefficient as bandwidth is equally spread across simple and more complex video scenes.
A more efficient method is to pool together the available bandwidth for several sub-channels and apply active variable bitrate (VBR) encoding per sub-channel in order to increase overall picture quality and free up bandwidth for the channels that need it most at any point in time.
The Flexibility of a Software Approach
Video providers are able to quickly scale up and introduce new features thanks to the inherent agility of software -defined video solutions which are differentiated in part by the ability to migrate changes and improvements amongst different codecs such as MPEG-2 and H.264. This is not possible with hardware-based solutions for video compression.
For more aggressive unified headend strategies, encoders can ingest 4K UHD or HD content and transcode it into parallel HEVC UHD and MPEG-2 or H.264 HD and SD streams, allowing a single system to create multi-resolution channel outputs from a single source.
Figure 2 – Elemental Statmux Allows Simultaneous Muxing for Ultra HD, HD and SD
Support for multiscreen video delivery requires software-based solutions that are nimble enough to accommodate rapid change while simultaneously maintaining the reliability required for 24/7 services. To start, the evolution of streaming protocols and monetization strategies for over–the-top services requires an advanced origin server, such as Elemental Delta, to perform just-in-time packaging, streaming and DRM. A software-based statistical multiplexer also is necessary for analyzing the frame-by-frame complexity of incoming video across multiple sub-channels while a bitrate controller sets the target bitrate levels of each encoder so that their total matches the full bandwidth available. The addition of multi-resolution support advances the idea of statistical multiplexing by enabling new services, including the creation of mux pools containing UHD 4K channels along with HD and SD channels, allowing network operators to thoroughly optimize bandwidth usage.
Figure 4 – Bandwidth Savings in a Multi-resolution, Multi-codec Mux Pool
In contrast to most hardware-based equipment, Elemental Statmux can potentially operate as part of a linear TV solution embedded within the encoder or as a standalone system, requiring minimal rack space and easily duplicated to a standby system for full redundancy. There are many reasons linear TV providers may need to upgrade their infrastructure, including natural cyclical equipment updates or the introduction of new services such as 4K Ultra HD TV broadcasts or advanced live-to-VOD. Relying on dedicated hardware is becoming an increasingly complicated and unattractive strategy for most providers compared with using software platforms that are more flexible and scale with increased demand for expanded services. Software solutions from Elemental support MPEG-2, H.264 and HEVC and include statistical multiplexing with the ability to mix resolutions and codecs on the same mux channel. This opens many different possibilities for pay TV operators and enables a smooth migration path from legacy standards.
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