Intra-coding macroblocks (MBs) is a fairly efficient way to make the compressed video bitstream more resilient to channel error because the decoding of an intra MB does not need the information from previous frames. However, too many intra-coded MBs will significantly degrade the compression performance. Therefore, a good mode selection between intra-mode and inter-mode should be in place to enhance the robustness of the video communications system to channel error. Since Rate-Distortion optimized (RDO) video coding framework can provide an efficient means for coding mode selection in an error-free environment, recent researches propose to extent this RDO framework in error-prone environment to intelligently decide which MBs should be intra-coded to better combat the transmission error.