## 2 Related Work  
Media production is adopting drones as replacements for dollies (static cranes) and helicopters, as their deployment is easier and has less costs associated. Thus, the use of drones in cinematography has increased recently, in parallel with the improvement on their technology. For instance, the New York City Drone Film Festival ([[https://www.nycdronefilmfestival.com](https://www.nycdronefilmfestival.com)]([https://www.nycdronefilmfestival.com](https://www.nycdronefilmfestival.com)).) was the world's first film festival dedicated to drones in cinematography. Besides, drones are quite attractive for live coverage of outdoor events, as they can provide novel angles and visual effects. In October 2016, drones were relevant for news agencies in the coverage of the massive destruction caused by Hurricane Matthew on Haiti [2]. They have also been used in major international sport events, such as the Olympics [3, 4]. In the current state-of-the-art solutions for media production with drones, the director usually specify targets subjects or points of interest to be filmed in pre-production, together with a temporarily ordered script, the camera motion types, etc. Then, the drone pilot and the cameraman must execute the plan manually in a coordinated fashion. There are also commercial drones, such as DJI [5], AirDog [6], 3 DR SOLO [7], or Yuneec Typhoon [8], that can implement certain cinematographic functionalities autonomously. However, they are typically prepared to track a target visually or with a GNSS and keep it on the image frame (_follow-me_ mode), not focusing on high-level cinematography principles for shot performance. Besides, there are some end-to-end solutions for semi-autonomous aerial cinematographers [9; 10]. In these works, a director specifies high-level commands such as shot types and positions for single-drone shooting missions. Then, the drone is able to compute autonomously navigation and camera movement commands to execute the desired shots, but the focus is on static scenes. In [9], an outdoor application to film people is proposed, and different types of shots from the cinematography literature are introduced (e.g., close-up, external, over-the-shoulder, etc.). Timing for the shots is considered by means of an easing curve that drives the drone along the planned trajectory (i.e., this curve can modify its velocity profile). In [10], an iterative quadratic optimization problem is formulated to obtain smooth trajectories for the camera and the look-at point (i.e., the place where the camera is pointing at). No time constraints or moving targets are included. In general, these approaches use algorithms to compute smooth camera trajectories fulfilling aesthetic and cinematographic constraints, which can be formulated as an optimization problem [11; 12; 13]. In a multi-drone context, there is little work on autonomous systems for media production. In [14], the optimal number of drones to cover all available targets without occlusion is computed. However, cameras must always be facing targets and smooth transitions are not considered. A more advanced method is presented in [15], where they propose an online planning algorithm to compute optimal trajectories for several drones filming dynamic, indoor scenes. User-defined aesthetic objectives and cinematographic rules are combined with collision and field-of-view avoidance constraints, but they do not address interfacing with the media director. Regarding user interfaces, there exist several drone _apps_ to support photographers, video makers, photogrammetrists, and other professional profiles during their activities. As relevant features, they usually include drone mapping, geo-fencing, and flight logging. In particular, based on regulatory information from each country, some apps can help users indicating no-flight zones such as airports, control zones (CTZ), etc. Local meteorological information (e.g., wind speed, direction, temperature, etc.) is also used in some apps to inform the pilot about flight safety.