Original technical solutions were used for recording this corpus.
Audio recording. In order to avoid the problem of file synchronization, the speech of the communicants was recorded with the help of a professional ZOOM Handy Recorder which allowed automatic synchronization. The following parameters were used for the recording: 96 kHz / 24 bit. The speech of each communicant was recorded with an individual lapel microphone SONY ECM-88B (used for the sessions of 2015) and a wireless vocal microphone Sennheiser ew500 (used for the sessions of 2017) in the mono mode. The fourth common (overall) recording in the stereo mode was made with the recorder’s built-in microphone (for the sessions of 2015) and a Sennheiser MKH 416 stereo microphone (for the sessions of 2017).
Video recording was conducted with three individual industrial video cameras JAI GO-5000M-USB with a frame rate of 100fps and a resolution of 1392×1000, thus taking a close-up of each of the three interlocutors. For further analytical work, it is crucial to keep in mind that these cameras allow making a recording in the mjpeg format; in comparison with other formats, the given format has a significant advantage of lacking inter-frame compression; this is a necessary prerequisite for conducting the subsequent frame-by-frame annotation. The frame rate of 100 fps makes it possible to analyze the video footage with precision up to 10 ms, which is an indication of high precision for the process of annotation. Apart from that, a common GoPro Hero 4 camera with a frame rate of 50 fps and a resolution of 2700×1500 (for the sessions of 2015) and with a frame rate of 120 fps and precision of 1920×1080 (for the sessions of 2017) was taking a cover shot.
For eye movement detection, two eye trackers were used, both Tobii Glasses II Eye Tracker with a frame rate of 50 Hz and a resolution 1920×1080. These eye trackers have a built-in miniature camera which registers the participant’s eye movements while a second camera is making a video of the scene; a built-in microphone records the incoming audio signal. This model of eye trackers has been available since December 2014, and it has been actively used in marketing research as well as in sports and in the field of driving safety. To our knowledge, these kinds of eye trackers have never been used in cognitive research of multichannel communication.
Eye trackers and industrial video cameras impose specific requirements on the choice of lighting equipment. Lighting has to be powerful (1000W or higher), however daylight fluorescent lamps or LED light cannot be used in this case as at the specified frame rate there is a visible effect of brightness oscillation (blinking). For these recordings, we used professional equipment for photo and video shooting, which included halogen lamps, softcams, and tripods. The overall capacity of lamps fluctuated from 2000W to 2500W depending on the amount of daylight (for the sessions of 2015). During the sessions of 2017 daylight was excluded, and the overall capacity of lamps amounted to 3000W.
