The monoscopic video plus depth map 3D video representation is widely considered in research and standardization activities due to its simplicity and adaptability . The colour image sequence is projected to the 3D space based on the depth pixel values, and this method is commonly known as Depth Image-Based-Rendering (DIBR) . Moreover,this format can be utilized to provide backward compatible 3D video services, where conventional users can view 2D video content by neglecting the depth map stream. With this representation, colour video is the only texture information that is directly viewed by the users. Therefore, the loss of colour video packets will be more noticeable to users (i.e., both 2D and 3D viewers) than the loss of depth video packets. Furthermore, the colour video itself provides certain depth cues (e.g., identification of objects in the foreground and background) during 2D viewing. Therefore, the colour video stream should be allocated more protection compared to the depth map packets in general.
Detailed depth maps are required to generate good quality 3D video using the DIBR technique, especially when the rendering view is too far from the original view. However, the quality of the depth map does not need to be significantly high to render good quality stereoscopic video content which is approximately 6cm apart. For example, the effect of depth map compression on depth perception is not significant according to. Furthermore, the effect of depth map transmission errors on the quality of reconstructed 3D video is insignificant compared to the quality degradation due to the loss of colour video packets. The study in also highlights the importance of prioritizing colour video data ahead of depth map information in order to improve the perceived 3D video quality. Moreover, the quality evaluation carried out in  shows that the effect of packet losses on depth perception is lower compared to the effect of packet losses on overall image quality. The scheme proposed in this paper therefore allocates higher priority for the colour image stream than the depth map stream to improve the overall quality of received 2D/3D video.
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