28 TVBEurope Forum Transcoding Breaking the code
Why is the broadcast industry always burdened with multiple formats and delivery platforms? In another TVBEuropeinitiative, Philip Stevens asks industry experts about the complex world of television transcoding
MULTIPLE FORMATS started from the dawn of television with the rivalry between the Baird set up and EMI’s electronic system. Then we went through PAL, SECAM and NTSC. Today, the formats are all about digital activities. And if various formats were not enough to concern the industry, there is now the question of multiple delivery platforms. So, what are the issues surrounding transcoding? Here with some of the answers are (in alphabetical order) Bruce Devlin, CTO at AmberFin; Pedro Ferreira, CTO of
What are the major workflow considerations where transcoding is involved?
Devlin: In all transcode situations it’s important that the transcoder is a workflow enabler and not a hindrance. This means it must be tolerant with what you read; be strict with what you write; be nice to the storage; allow humans to use GUIs; allow simple systems to use watch folders; and allow complex systems to use web service APIs. Ferreira: To make it as seamless as possible, both in terms of quality but also, very importantly, in terms of transparency for the operators. The more the operator is unaware of it, the better. Nann: Depending on
the application one key consideration continues to be the diversity and fragmentation of technical requirements between viewing devices, which means that most transcoding workflows involve multiple concurrent outputs. Even with the current ubiquity of the H.264 format across platforms and devices, there continue to be differing standards for ‘packaging’ metadata and delivery protocols that result in incompatibilities between devices. The adaptive streaming technologies commonly deployed exemplify the challenge. While they share common concepts and overlap
in a number of technical aspects, they are not compatible with each other. Most significantly, none of these technologies is universally supported across all platforms and devices, often forcing content providers to deploy at least two of them in parallel to reach all target viewing devices. The cliché that ‘the great thing about standards is that there are so many of them’ is fully applicable here. Sassoli: From a technology standpoint, the beauty of adaptive bitrate streaming is that the actual transcoding workflows are very similar for all delivery methods, whether linear or VoD. Both require multi- bitrate transcoding and both require packaging, in realtime or on demand. There are, however, differences in how channels are published in an EPG versus how assets are managed for VoD or network DVR. Turner: Engineers should consider several topics when designing file-based workflows. Obviously, image quality is a very high priority. But there really is no ‘one-size-fits-all’ transcoder. The designer should use an input transcoder at the input stage, a ‘hub’ transcoder to ensure that processors are given the most appropriate file format within the processing core of the workflow, and a distribution transcoder when a single asset needs to be
MOG Technologies; Mike Nann, director of Marketing and Communications at Digital Rapids; Simone Sassoli, vice president, RGB Network’s Marketing and Business Development; Ian Trow, senior director of Emerging Technology and Strategy at Harmonic; Paul Turner, vice president of Enterprise Product Management at Telestream; Owen Walker, head of Product Management, Root6 Technology; and Keith Wymbs, VP of Marketing, Elemental Technologies
What is the likely impact of HEVC/H.265?
Bruce Devlin: “In all transcode situations it’s important that the transcoder is a workflow enabler and not a hindrance”
Ferreira: It is difficult to imagine, as we are still far from exploring the true potential of its predecessor, AVC. As an example, it has taken the industry almost two decades to embrace Long GOP MPEG-2. It was faster to adopt AVC-I, as we were already more prepared for this kind of technology but, strangely or not, it is taking a while to adopt Long GOP AVC. Maybe with HEVC, the industry will take a bolder step and dive into Long GOP structures in
Ian Trow: “Broadcasters require unified platforms that support multiple services”
www.tvbeurope.com July 2013
Mike Nann: “There continue to be differing standards for ‘packaging’ metadata and delivery protocols that result in incompatibilities”
Keith Wymbs: “Unification is a major aspiration and something that we focus on at Elemental”
distributed in many formats simultaneously — for multiscreen delivery, for example. An area that many designers neglect is the system’s ability to translate/transform non-media items — ANC, timecode, etc. We live in a world where metadata is omnipresent, and a single error in translation can render a piece of media useless — at least until the error is detected and corrected.
“HEVC will have a major impact in the coming years with its potential to reduce bandwidth requirements and file sizes by as much as 50% relative to AVC” Mike Nann
production, justifying another technology change while we’re still trying to reap the benefits of the former generation. Nann: HEVC will have a major impact on the market in the coming years with its potential to reduce bandwidth requirements and file sizes by as much as 50% relative to AVC, with a myriad of benefits for various aspects of the television and media and entertainment
ecosystems — from lowering content delivery costs for both operators and consumers to enabling higher-quality viewing experiences on OTT and mobile video services without requiring more bandwidth and enabling higher-resolution service offerings beyond HD. Sassoli: HEVC holds great
promise, and will have major impacts on transcoders — possibly resulting in ‘forklifts’
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