Video Conferencing Applications (VCAs) are widely used in education and remote work. Realistic modeling of VCAs, especially proprietary VCAs, enables simulation of VCA behaviors under network conditions that are different from those where the VCAs are deployed. Models of VCAs can be useful for both network operators and VCA developers who can assess how sensitive a VCA is to changes in the network. For instance, if VCA A begins to suffer video quality degradation when end-to-end delay exceeds 100 ms, while VCA B's corresponding threshold is 200 ms, operators can decide to give priority to A's traffic for better overall user experience. Additionally, modeling helps VCA designers select parameter values to navigate inherent performance trade-offs. If a model can quantify, for instance, how increasing a certain threshold to enhance video quality stability may increase frame latency, designers can make informed choices.