Analysis of synchronization issues for live video-context transmission service

摘要

A promising feature brought along the progressive deployment of LTE concerns the increase of the uplink bandwidth. We exploit this new capability by focusing on an innovative usage defined by the simultaneous transmission of live video and contextual data caught through end user devices like smartphones towards websites or distant spectators. The contextual information may indeed be precious to the spectator for several reasons. On one side, this information cannot be deduced from the video images currently displayed. On the other side, being closely related to the live event, context can be fruitfully exploited by the spectator to complete her understanding of what she is presently watching and to possibly interact with the filming person to influence the rest of the capture. The main property of this new feature can be expressed as a synchronization constraint between the video and the contextual data. Ensuring this property is challenging due to the presence of variable delays in the end-to-end path. We focus on particular contextual data (generated by sensors embedded in Android based smartphones) the specificities of which are analyzed in order to derive a general synchronization solution. We finally propose some optimizations taking in account the characteristics of the devices used to display the contextual data.