Synchronization Mechanisms for Live Video-Context Transmission Service
Résumé
A promising feature brought along the progressive deployment of LTE concerns the increase of the uplink bandwidth. We focus in this paper on an innovative usage associated with this new capability and defined by the simultaneous transmission toward websites or distant spectators of live video caught through end user devices like smartphones, together with contextual data generated by the device. 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 currently displayed, context can be fruitfully exploited by the spectator to complete its understanding of what he 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. In this paper, we analyze this problem and propose optimization solutions taking into account the characteristics of the devices used to catch and exploit the contextual data. We show by simulations their effectiveness as compared to the current techniques. Our algorithms enable to verify the synchronization and to properly use the endpoint resources.