Understanding Couch Potatoes: Measurement and Modeling of Interactive Usage of IPTV at large scale

We investigate how consumers view content using Video on Demand (VoD) in the context of an IP-based video distri-bution environment. Users today can use interactive stream control functions such as skip, replay, fast-forward, pause, and rewind to control their viewing. The use of these func-tions can place additional demands on the distribution in-frastructure (servers, network, and set top boxes) and can be challenging to manage with a large subscriber base. A model of user interaction provides insight into the impact of stream control on server and bandwidth requirements, client responsiveness, etc. We capture the activity users in a natural setting, view-ing video at home. We first develop a model for the ar-rival process of requests for content. We then develop two stream control models that accurately capture user interac-tion. We show that stream control events can be charac-terized by a finite state machine and a sojourn time model, parametrized for major periods of usage (weekend and week-day). Our semi-Markov (SM) model for the sojourn time in each stream control state uses a novel technique based on a polynomial fit to the logarithm of the Inverse CDF. A sec-ond constrained model (CM) uses a stick-breaking approach familiar in machine learning to model the individual state sojourn time distributions. The SM model seeks to preserve the sojourn time distribution for each state while the CM model puts a greater emphasis on preserving the overall ses-sion duration distribution. Using traces across a period of 2 years from a large-scale operational IPTV environment, we validate the proposed model and show that we are able to faithfully predict the workload presented to a video server. We also provide a synthetic trace developed from the model enabling researchers to also study other problems of inter-est. We also use the techniques to model consumer viewing of video content recorded on their personal Digital Video Recorder (DVR)