原始安装包需要更新sources.list,经常连接失败。 离线包实测在ubuntu18.04,20.04,ubuntu21.04均可以正常安装使用，连接摄像头。 at_3.1.20-3.1ubuntu2_amd64.deb librealsense2_2.49.0-0~realsense0.5306_amd64.deb librealsense2-dev_2.49.0-0~realsense0.5306_amd64.deb librealsense2-udev-rules_2.49.0-0~realsense0.5306_amd64.deb libusb-1.0-0_2%3a1.0.21-2_amd64.deb