A CBR-streaming scheme for VBR-encoded videos

Media files are required to use variable-bit-rate (VBR) encoding, such as MPEG-2, in order to get constant quality compressed video. However, it produces traffic burst, which makes streaming complicated. Large network latency and jitter cause long start-up delay and frequent unwanted pauses in media playback, respectively. In this paper, we have proposed a proxy based constant-bit-rate (CBR) streaming scheme that allows a server to transmit a VBR-encoded video at a fixed rate, close to its mean encoding bit rate, and deals with the network latency and jitter issues efficiently without caching an entire media file. We have used smoothing buffers at the proxy to eliminate jitter and traffic burst effects. We have used prefix buffers at the proxy to cache the prefixes of popular videos to minimize the start-up delay and to enable near mean bit rate streaming from the server as well as from the proxy. Simulation results are presented to demonstrate the effectiveness of our streaming scheme.