Most of the rateadaptation algorithms are about the data frame rate. However, the rateadaptation algorithm about the control frames is still very rare.
但目前绝大部分速率自适应算法是针对数据帧的速率进行自适应，而针对控制帧的速率自适应算法还很少见。
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Motion Vector Refinement: Bit rateadaptation transcoding adapt the network heterogeneity, which makes the reference frame changed. The motion estimation is needed.
These codes, together with a flexible rateadaptation algorithm, allowed for a highly versatile variable rate configuration of the physical layer that could easily meet the flexibility needs of 3g.