System Overview

As introduced before, all the components cited above aim to empower group logging. Thus, when using the logjam system the group can use its various elements (see Figure 3) to efficiently log the video.
The game board is the central element of the infrastructure. Indeed, the ethnographers can use it for various tasks. First of all by placing a block on a special location on the board, one can assign it a category (e.g. interviewing, observing, dancing, group, crowd, couple, etc.). It is worth noting that the description of the category has still to be entered using a classical keyboard and GUI fields. Furthermore, the game board can be used for actual logging: dropping a block $b$ on the surface creates an annotation at current time $t$ in the category represented by $b$. Similarly, picking up $b$ after $n$ seconds ends the annotation at current time $t+n$.
Finally, the game board also serves for video speed control. Dropping any block on the back raw of the board controls the display velocity of the video.
The footpedals are also meant for this purpose. By pushing and releasing them one can control the video speed.
Eventually, the classical GUI permits everything the TUI offers plus prompts for (textual) input when required (e.g. when creating a new category).