The continuing growth in the mobile phone arena, particularly in terms of device
capabilities and ownership is having a transformational impact on media
consumption. It is now possible to consider orchestrated multi-stream experiences
delivered across many devices, rather than the playback of content from a single
device. However, there are significant challenges in realising such a vision,
particularly around the management of synchronicity between associated media
streams. This is compounded by the heterogeneous nature of user devices, the
networks upon which they operate, and the perceptions of users. This paper
introduces IMSync, an open inter-stream synchronization framework that
incorporates human factors to capture the quality of experience (QoE). IMSync
adopts efficient monitoring and control mechanisms, alongside a QoE perception
model that has been derived from a series of subjective user experiments. Based
on an observation of lag, IMSync is able to use this model of impact to determine
an appropriate strategy to catch-up with playback whilst minimising the potential
detrimental impacts on a users QoE. The impact model adopts a balanced
approach: trading off the potential impact on QoE of initiating a re-synchronization
process compared with retaining the current levels of non-synchronicity, in order
to maintain high levels of QoE. A series of experiments demonstrate the potential
of the framework as a basis for enabling new, immersive media experiences.
