In this article, we propose a 2D to 3D video conversion scheme for MPEG videos. The difficulty for 2D/3D conversion problem lies on depth estimation/ assignment with insufficient information. Our depth assignment is based on the analyses of multiple cues, e.g., motion parallax, atmospheric perspective, texture gradient, linear perspective, and relative height, separately for the foreground objects and the background area. To fit more kinds of videos, the proposed depth assignment scheme is content-adaptive by segmenting a video into shots and classifying each of them into three categories for different conversion schemes. Subjective experiments show that the 3D stereo video generated by using our depth assignment scheme and the Depth Image Based Rendering (DIBR) technique presents little difference to that created based on the depth ground truths.