I put my solution here, try to build 32bit Unity3d and plugin. Recently I build Unity3d project in Linux 64bit. The project need to analysis web camera it only support MJPEG format, MJPG format seems could not be captured by using WebCamTextrure() directly on Linux. (By the way, MJPG format seems can be analysis on Windows 32bit/64bit normally.) So I developed plugin that using libjpeg to analysis web camera.