SCORE: Exploiting Global Broadcasts to Create Offline Personal Channels for On-Demand Access

Gianfranco Nencioni, Nishanth Sastry, Gareth Tyson, Vijay Badrinarayanan, Dmytro Karamshuk, Jigna Chandaria, Jon Crowcroft

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)
230 Downloads (Pure)


The last 5 years have seen a dramatic shift in media distribution. For decades, TV and radio were solely provisioned using push-based broadcast technologies, forcing people to adhere to fixed schedules. The introduction of catch-up services, however, has now augmented such delivery with online pull-based alternatives. Typically, these allow users to fetch content for a limited period after initial broadcast, allowing users flexibility in accessing content. Whereas previous work has investigated both of these technologies, this paper explores and contrasts them, focusing on the network consequences of moving towards this multifaceted delivery model. Using traces from nearly 6 million users of BBC iPlayer, one of the largest catch-up TV services, we study this shift from push-to pull-based access. We propose a novel technique for unifying both push-and pull-based delivery: the Speculative Content Offloading and Recording Engine (SCORE). SCORE operates as a set-top box, which interacts with both broadcast push and online pull services. Whenever users wish to access media, it automatically switches between these distribution mechanisms in an attempt to optimize energy efficiency and network resource utilization. SCORE also can predict user viewing patterns, automatically recording certain shows from the broadcast interface. Evaluations using our BBC iPlayer traces show that, based on parameter settings, an oracle with complete knowledge of user consumption can save nearly 77% of the energy, and over 90% of the peak bandwidth, of pure IP streaming. Optimizing for energy consumption, SCORE can recover nearly half of both traffic and energy savings.

Original languageEnglish
Article number7210228
Pages (from-to)2429-2442
Number of pages14
JournalIeee-Acm Transactions On Networking
Issue number4
Early online date19 Aug 2015
Publication statusPublished - Aug 2016


  • Content distribution networks
  • digital TV
  • digital video broadcasting
  • energy conservation
  • energy efficiency
  • environmental factors
  • machine intelligence
  • recommender systems
  • TV broadcasting
  • TV receivers

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