Computer-implemented techniques include detecting, using a camera of a computing device having one or more processors, a digital watermark displayed by a display of a computing system. The digital watermark can be a visual indicator that is detectable by the camera of the computing device, and the computing system can further comprise a set of speakers and a set of cameras. The techniques can include determining, by the computing device, a unique identifier for the computing system based on the digital watermark. The techniques can also include automatically coordinating, by the computing device, an audio/video conference session between the computing device and the computing system using the unique identifier.