The Internet has been experiencing a large growth of multimedia traffic of applications performing over an RTP stack implemented on top of UDP/IP. Since UDP does not offer a congestion control mechanism (unlike TCP), studies on the rate control schemes have been increasingly done. Usually, new proposals are evaluated, by simulation, in terms of criteria such as fairness towards competing TCP connections and packet losses. However, results related to other performance aspects—quality achieved, overhead introduced by the control, and actual throughput after stream adaptation—are difficult to obtain by simulation. In order to provide actual results about these criteria, we developed a comprehensive live video delivery tool for testing RTP-based controllers. In this version of the tool, the video is encoded on the fly in the MPEG-2 standard, but we intend to use the H.264/AVC standard as soon as common PC's provide enough processing power to encode H.264/AVC live video. The tool allows to easily incorporate new control schemes. In this paper, we describe the tool architecture and some implementation details. We also evaluate the performance of the tool itself, in terms of efficacy, accuracy, and efficiency.
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