This paper describes the open and flexible architecture of a stereo vision system prototype, using open source software. The system is designed for teleoperated robots and includes a four degrees of freedom stereo head mechanism, a pair of high performance digital cameras, a head tracker and a head mounted display. All processes for the head control and video streaming are performed in Linux-based Real-time Operating Systems using open source libraries under GPL license. Experimental results showed that our system is capable of satisfying the hard-real time requirements for the head control, with great precision, and a low latency for the stereo video streaming. The video streaming management is particularly sophisticated resulting in a flexible, efficient and reliable service.