¶ Design the telepresence space
To design a telepresence project, it is essential to clearly define its intention and to implement it taking into account the overall experience; the design of the space must be carried out according to a coherent artistic vision for all points of view – in the presence, as well as from a distance. This overall vision must include all connected places and consider both the spatial characteristics of the physical spaces used and their respective representations. The ensuing stage pre-production work can become quite complex and often requires the involvement of the technical managers of each location. Indeed, to properly assess the scenic possibilities offered by each space, the floor plan is not enough; the interaction with a physically present person makes it possible to have a more accurate idea of the real constraints of a space. To summarize, here is a list of recommendations for preparing the staging of the spaces involved:
- Have a person responsible for the overview in each room. For each point of view to be coherent, a balance must be found between them in the staging. It is a constant compromise between the points of view of each of the audiences;
- Make a plan illustrating the installation of each of the rooms to better assess their scenographic coherence and share it with the other people involved in the project;
- Establish direct communication with the managers of each location involved to get the facts on the real constraints and possibilities of the space used.
Thoughts:
- Where are the cameras placed?
- From what point of view do we want to see such a protagonist in the other room?
- What is seen in the eye of the camera that we want to see in theaters?
- Where are the projection surfaces?
- Where in the room should what is filmed from the other place be screened?
- Is the local and/or distant public captured and projected in the rooms?
- What distance should the camera be to have the most interesting framing for the proposed experience? Are the cameras fixed or can they change position during the show?
- What is the difference in the architecture of each of the rooms that influences what is sent to the other rooms?
¶ Balance of spaces
The type of space, its configuration, its size all influence the telepresence experience between places. It is important to consider whether it is desirable to have a similar or different experience for each location involved. In general, the more one resorts to a symmetrical arrangement between the places – such as a face-to-face arrangement, the more one tends to reproduce the conditions similar to a natural communication between the parties. In this case, the mirror layout is ideal in cases where the emphasis is on the meeting and the exchange between people. Conversely, artists could also choose to create completely different spaces, either to create a unique experience in each of the places or to give a more ambiguous impression as to the nature of the distant place.
In theatre, uneven sets often serve to manifest a dramatic difference between the spaces in play, while equal sets rather give the impression of an equivalent or balanced dramatic ratio.
In the show Tshimushuminutsh, the two sets are equal; the experience is similar and the two speakers are dramaturgically equal.
In the cinema, when the optical axis of capture of the camera is not horizontal, the shots are then either from above or from below:
- Diving: when the view is taken from a point of observation higher than the subject;
- Low angle: when the point of view is lower than the main subject.
Depending on the situation, these shots are used in particular to induce a dramatic effect on the object or subject captured, such as an effect of crushing and fragility for shooting from above or, on the contrary, an effect of scale and power for low angle shots.
In scenic telepresence, these strategies, from both theater and cinema, can be combined.
Examples:
- A group of students from the National Theater School created a theatrical experience where a group of performers from a small hall interact with a large theater hall. The spectator only had access to snippets of the other place, thus giving an effect of fragmentation in connection with the dramaturgy used.
The visual projection on a human scale and the exchange of gazes promote the impression of presence by reproducing the natural conditions of a conversion in person. In opposition to this feeling, the work on the different sizes of projection gives different relationships between the characters. For example, the close-up of a performer often creates a connection with the audience and a different relationship with the smaller physical body on stage. The movement of the cameras and the changes of shot more typical of cinema add a more omniscient narration by the image.
Thoughts:
- Do we want a similar or different experience in each location?
- Is it desirable to simulate the conditions of natural communication between people from different places?
- Do we want to achieve a dramatic effect or illustrate an asymmetrical relationship between the spaces?
- Is it better to play on the balance between the sets, on the shooting of the cameras or on a combination of the two?
¶ Reproduction of a natural communication
In telepresence, it is generally desirable to reproduce an interaction that seems natural between people who are physically present and those who are distant. Visual projection on a human scale (size) and the interaction of gazes, for example, are strategies that all promote a feeling of presence by effect of realism.
The realism effect (or mimesis) is based on the anthropomorphic cognitive process and describes any strategy or any aspect of an interaction that is rooted in situations or cognitive parameters encountered in the real world. The realism effect - that is, the subjective recognition of a certain level of verisimilitude - therefore tends to provide a context conducive to the adoption of a mimetic interpretative behavior that is generally inclusive and sufficiently intelligible for ordinary mortals.
This is why the most frequently used telepresence devices tend to use, as far as possible, the usual codes of interpersonal communication, in order to minimize the immersive gap induced by the intermediary of a telecommunication technology. In particular, they make it possible to optimize empathy, proprioception and reproduce several elements of natural communication in physical presence.
However, given that the architectures of connected places are never identical, it is often preferable, even necessary, to play with the differences in the implementation.
Examples:
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In 1993, the installation Telematic Dreaming by Paul Sermon gives the impression that participants from distant places are sitting on the same bed;
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In the creation Bluff is an example where at many times a communication seems natural and the protagonists seem to be side by side.
Here are the things observed:
- For eye contact between participants, the camera is placed at eye level with the projection of the distant person.
- To allow the expression of non-verbal language, the framing is wide and the camera is straight in front of the subject.
- The projection of the distant characters is in scale 1, real size, and the large screens are placed at ground level so that the characters can be seen from head to toe.
- It is necessary to position the projected character well to align the gaze.
¶ Equipment and configurations
Depending on the objectives to be achieved, different equipment can be used, or even necessary, for carrying out telepresence projects: cameras, projectors, projection surfaces, microphones, audio monitors, adapters, cabling, lighting, computer systems, software, motion sensors, etc. movements, actuators, connected objects and more.
¶ Video
In telepresence, video capture and projection are important aspects. The images of places and subjects must be transmitted and then visible in other places.
¶ Cameras
The type of camera, its positioning, the framing used or its settings will influence the quality of the image.
Thoughts:
- What level of light will be used during the project? If the camera is to be used indoors in low light, it is advisable to opt for a light-sensitive camera.
- Will the camera be on stage? What format should it have? A compact format is often preferable to limit its visual influence.
- What angle of view is necessary on the filmed subjects? Usually, standard lenses make it possible to respect the proportions on a human scale. Wide-angle lenses make it possible to capture a wider area, such as when filming an entire audience.
To learn more about the technical aspects of video display, see the section Use the right type of camera of Good technical practices for scenic telepresence.
¶ Positioning and framing
The location of the cameras – whether they are located on stage or in the room, operated in a fixed or mobile way – is a very decisive decision.
¶ Fixed
If the cameras and projection surfaces remain fixed in the same place throughout the performance, make sure to configure the space so that the cameras do not interfere with the visibility of the public or the projection surfaces.
This type of installation has the advantage of offering the public a constant, clear and comprehensible benchmark. The lack of mobility of the cameras also favors the impression of a virtual « window » on the distant space and is less likely to break the effect of co-presence that visual stability makes it possible to establish between the places. Indeed, any camera movement reminds the audience of its existence and that the media experience is not intentionally neutral.
¶ Mobile
The use of mobile cameras, on the other hand, requires that we accept that the technical equipment is sometimes visible and that it can even play a role in the general choreography. Whether they are handled by the interpreters or by an operator, on the shoulder or remotely (robotic cameras), mobile cameras make it possible to broaden the possibilities of shots and framing. For example, a wide shot will provide a general perspective of the space, while a close shot will promote a feeling of intimacy with the performer.
In the Bluff show, at times the camera is positioned facing the audience so that you have the 1:1 scale performer in the foreground and the audience behind. Thus, we install a large assembly in 360 degrees where the public see each other.
¶ Visual representation at natural scale
To create a space where communication between places is as natural as possible, a few basic recommendations apply:
- Position the camera in a frontal position, with no angle, so no high angle or low angle effect;
- To promote eye contact, camera height should match subject’s eye height, otherwise waist height for a full-length shot;
- Adapt the distance and the zoom of the camera in order to obtain an image of the subject of a human size (1:1);
- Perform a projection test to compare the size of the projected subject with that of the present subject, side by side. It is recommended to adjust the projection so that the size of the projected subject is 5-10% larger than the present subject. This notably makes it possible to amplify the presence of the distant subject, whose flattening of the projection tends to reduce;
- To achieve a corresponding size scale between locations, it is best to have similar projectors, projection surfaces and cameras – ideally, with the same settings (position relative to subject, zoom, focus, level of white, color level, etc). Otherwise, the parameters of the cameras in each location must be manually adjusted to achieve an apparent equivalence of sizes;
- Angle of view: does the camera capture all the essential elements?
- When a camera captures subjects from the front, it must be parallel to them;
- During multi-camera events, it is best to avoid overlapping shots; it is not desirable for a subject to be duplicated on more than one shot at the same time, which would risk harming the effect of presence.
¶ Video Processing
There are several video processing software to develop an optimal image composition for telepresence, including Studio OBS (integrated in the SCENIC station), Modul8, Madmapper, Millumin, Resolume. With SCENIC, video processing can be done in real time on the image stream and then sent to the various connected locations. To combine cameras on the same video input, adding a video selector is required.
¶ Projection area
The use of different types of projection screens makes it possible to specify the artistic intention. We can thus develop scenographies where the projection surfaces have different degrees of opacity, different shapes and textures.
Here are some examples of possible scenographic effects depending on the type of projection surface:
- Opaque and rigid panels: for a clearly visible projection that captures the light well.
- Tulles, mosquito net, glass, plastic film: to play with the transparency or the superposition of the subjects.
- Spandex or other stretch fabrics: to touch and manipulate the projection.
- Pepper’s Ghost technique (https://fr.wikipedia.org/wiki/Fantôme_de_Pepper)*: to create a holographic presence.
- Rear projection screens: to position elements right in front of the screen without image blocking or shadows.
- D.E.L. screens: to optimize the visibility of images, without alteration by stage lighting and it is ideal when you want to film a projection.
- Use the subjects or performers on stage as a projection screen: to create a different effect on the relationship between present and distant performers.
In the show Onirisme, the artist Isabelle Clermont uses spandex as a decorative element to create a tactile relationship with the video projection.
The LED screen is used by director Françoise Dancause in her show CorresponDanse de guerre to film characters from the other place.
Screens can be positioned in different ways in space and their size greatly influences the experience. Often, the rooms are equipped with a large screen in the background. Although its size makes it possible to have a large surface, it is necessary to use creativity so that the interpreters interact with a projection which is behind them. The use of screens in the game space allows an easier relationship between the present and distant subject. For example, a screen the size of a human and positioned vertically on stage reinforces the illusion of the real presence of protagonists located in another place and the people on stage then interact more naturally with the projection. In the early explorations of the Bluff project, simple banner stands were used.
To learn more about the technical aspects of projection surfaces, see the section Use the correct video display type of Good technical practices for scenic telepresence.
¶ Video projectors
Depending on the surfaces available, the type of projection may vary. Unless you are using video mapping software, be sure to point the projector beam directly at the screen, whether front or rear projection. It should also be taken into account that some rooms do not all offer the same flexibility as to the location of the projectors and their distance from the projection surface.
- The larger the surface and the more the space is lit, the more powerful the projector must be for the image to remain fairly precise;
- Wide-angle projectors, with a short focal length, are to be considered when space is more limited since they can be placed closer to the surface without reducing the dimensions of the projection too much.
To learn more about the technical aspects of video projection, see the section Use the correct video display type of Bonnes pratiques techniques en téléprésence.
¶ Éclairages
Intégrer une ou plusieurs projections vidéo à la scène requiert un juste équilibre entre l’éclairage de scène, nécessaire pour que les caméras captent une image de bonne qualité, et celles des projections lumineuses sur les écrans. Le bon calibrage de la lumière sur les sujets sur scène en fonction de la puissance de la projection s’avère un défi récurrent qu’il ne faut pas négliger.
Pour en savoir plus sur les aspects techniques de la projection vidéo, consultez la section Utiliser le type d’éclairage approprié of Good technical practices for scenic telepresence.
¶ Audio
¶ Microphones
In telepresence, the sound must be captured, processed and compressed before being transmitted to the other location(s). Ideally, one microphone (hypercardioid, unidirectional or dynamic) is provided per participant and to avoid feedback (feedback), omnidirectional microphones are prohibited. It is therefore difficult to capture the public as a whole. In some projects, where there are interventions from the public, the option of using a mobile microphone can be interesting. For example, a Catchbox type microphone can be thrown at participants wishing to express themselves.
In the project Masq’ensemble, young people used a Catchbox type microphone to easily pass the floor.
¶ Sound latency
Although the transmission delay (latency) inevitable in broadcasting between locations limits the phenomenon of sound recursion at the origin of feedback, it causes an echo phenomenon. Like feedback, the louder a sound is emitted from the speakers and picked up by the microphones, the more the system amplifies the echo phenomenon.
To counter the echo, it is necessary to maintain a sufficiently large dynamic difference between the desirable sound (having a higher sound level) and the undesirable sounds (having a lower sound level), in order to optimize the effectiveness of the gate ( “noise gate”), applied to each slice of the sound mixer receiving a microphone signal. This is achieved by placing the main speakers further away and pointing them away from the microphones. Conversely, the microphones are positioned as close as possible to the source to keep the input gain level low.
To learn more about the technical aspects of picking up and receiving audio signals, see the section Audiovisual Considerations of Good technical practices for scenic telepresence.
¶ Spatialization
Distributing sound sources spatially across a number of speakers generally provides a better listening experience for the audience. It promotes immersion and maintains consistency between image and sound. For example, if we position the sound source that transmits the voice of a person located in another room at the place where his image is projected, we help the audience to better determine the origin of the voice, in addition to facilitate its decoding by the vision of the lips.
To learn more about the technical aspects of indoor sound broadcasting, see the section Spatialize sound sources of Good technical practices for scenic telepresence.