Semiduplex audio streaming server and client

We are looking at creating the following scenario: A software client installed on a PC, using its soundcard, records and sends audio from the microphone to a server. This audio is then re-sent from the server to a number of clients, who then play it back on their speakers. The idea is for a multi-site PA system. Project constraints: - No royalty code or components allowed (i.e. codecs, etc.). - Code to be written in Qt preferably, so our coders can implement the solution into our CRM. - Solution can be based in SIP and RTP, but the network overhead must be very low. - For the server, modifications of existing platforms to allow this model of one-way audio are permitted, with clear description of the process and platform in your bid. - The server must be scalable to support thousands of clients. - A simple client GUI must be provided, but with no fancy graphic requirements - this is going to be implemented into our own code, so we need a working framework for testing, nothing more. More details can be given to bidders upon review of their references. Please do not bid if you have no experience in voice systems, SIP/RTP, audio codecs and high-performance scalable systems. ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Deliverables must be in ready-to-run condition, as follows (depending on the nature of the deliverables): a) For web sites or other server-side deliverables intended to only ever exist in one place in the Buyer's environment--Deliverables must be installed by the Seller in ready-to-run condition in the Buyer's environment. b) For all others including desktop software or software the buyer intends to distribute: A software installation package that will install the software in ready-to-run condition on the platform(s) specified in this bid request. 3) All deliverables will be considered "work made for hire" under U.S. Copyright law. Buyer will receive exclusive and complete copyrights to all work purchased. (No GPL, GNU, 3rd party components, etc. unless all copyright ramifications are explained AND AGREED TO by the buyer on the site per the coder's Seller Legal Agreement). ## Platform Windows XP, Linux, MacOS - portability to be realised using Qt.