Bitstream switching is an effective way to deal with bandwidth variation in transmitting multimedia over time-varying channels. A number of bitstream switching mechanisms have been proposed to reduce the potential error drift introduced by bitstream switching, often without explicitly taking into account the impact of the switching on the bandwidth and delay requirements in their performance analysis. This paper studies the relative rate-distortion (R-D) performance of some of these bitstream streaming mechanisms by extending a delay-aware R-D optimized dynamic bitstream switching framework we previously proposed. By considering different switching mechanisms, we show that the proposed extended R-D based framework can adaptively choose the right switching mechanism and effectively switch at the right time to the right bitstream to achieve optimized rate-distortion performance.