  Multimedia conferencing is the conversational exchange of multimedia content
between multiple parties. It has a wide range of applications (e.g. Massively
Multiplayer Online Games (MMOGs) and distance learning). Many multimedia
conferencing applications use video extensively, thus video mixing in
conferencing settings is of critical importance. Cloud computing is a
technology that can solve the scalability issue in multimedia conferencing,
while bringing other benefits, such as, elasticity, efficient use of resources,
rapid development, and introduction of new applications. However, proposed
cloud-based multimedia conferencing approaches so far have several deficiencies
when it comes to efficient resource usage while meeting Quality of Service
(QoS) requirements. We propose a solution to optimize resource allocation for
cloud-based video mixing service in multimedia conferencing applications, which
can support scalability in terms of number of users, while guaranteeing QoS. We
formulate the resource allocation problem mathematically as an Integer Linear
Programming (ILP) problem and design a heuristic for it. Simulation results
show that our resource allocation model can support more participants compared
to the state-of-the-art, while honoring QoS, with respect to end-to-end delay.
