Generally speaking, to avoid video codec problem with different computers, and ensure the properly video playback in PowerPoint, Flash video in FLV format and other video formats is not recommended to be inserted in PowerPoint. Based on the popularity of Adobe Flash player, which is widely installed on most computers in the world, Flash movie in SWF is highly compatible cross-platform and properly played back. You may try some video to Flash conversion tools, such as WebVideo Author, to convert FLV or other video formats to SWF format.