With MoVi the mobile phones collectively sense the surrounding ambiance to detect precursor signs (e.g., outburst of laughter, moves in the same directions) of relevant social events (e.g., speeches) and trigger a video recording of the upcoming events in case of positive detec- tion. The recordings collected by different mobile phones can then be timely and automatically assembled in a common video clip, which may potentially reduce cumbersome manual video edition. As the video recordings are automatically triggered, the partici- pants can focus on the events instead of having to focus on taking recordings.