Optimized Adaptive Streaming Representations based on System Dynamics

Adaptive streaming addresses the increasing and heterogenous demand of multimedia content over the Internet by offering several encoded versions for each video sequence. Each version (or representation) has a different resolution and bit rate, aimed at a specific set of users, like TV or mobile phone clients. While most existing works on adaptive streaming deal with effective playout-control strategies at the client side, we take in this paper a providers' perspective and propose solutions to improve user satisfaction by optimizing the encoding rates of the video sequences. We formulate an integer linear program that maximizes users' average satisfaction, taking into account the network dynamics, the video content information, and the user population characteristics. The solution of the optimization is a set of encoding parameters that permit to create different streams to robustly satisfy users' requests over time. We simulate multiple adaptive streaming sessions characterized by realistic network connections models, where the proposed solution outperforms commonly used vendor recommendations, in terms of user satisfaction but also in terms of fairness and outage probability. The simulation results further show that video content information as well as network constraints and users' statistics play a crucial role in selecting proper encoding parameters to provide fairness a mong users and to reduce network resource usage. We finally propose a few practical guidelines that can be used to choose the encoding parameters based on the user base characteristics, the network capacity and the type of video content

Are streaming and other music consumption modes substitutes or complements?

Abstract. From a representative survey of 2,000 French individuals, we study whether consumption of music through streaming services, such as Spotify or YouTube, is a substitute or a complement to other music consumption modes such as CD, Pay-downloads or live music. Controlling for the taste for music, various socio-demographic characteristics, as well as for the usual determinants of music consumption either offline (radio, TV, friends/relatives) or online (online recommendations, social networks), our results show that consuming music as streams (where the consumer does not possess the music but has just an access to it) has no significant effect on CDs purchase but is a complement to buying music online. The use of streaming services also affects positively live music attendance, but only for national or international artists who are more likely to be available on streaming services. These results suggest that a new music ecosystem is emerging in which the "possession" as well as the "access" modes of recorded music consumption might coexist