Hi Milon.<br>Yes I meant to say OLP.<br><br>The OTZ file extension is associated with the OpenLP free application used to create multimedia presentations for church worship services. The .otz file contains settings of church presentations including pictures, fonts, text colors etc.<br><br>Since OLP's themes/backgrounds/videos are in OTZ format, it would be easier to convert other freely downloadable themes/video backgrounds for use in OLP, only if one could find a software or ways for converting them. My google search revealed no joy.