Developed a video downloader software that can be used to grab videos from video sites with URL.Utilized the open source framework Electron to package and generate desktop applications, the software can exist independently from the browser.Utilized Angular framework as the front-end component.Achieved data connection between front-end (TypeScript) and back-end (Nodejs) by ipcMain and ipcRender.Developed video transformation function transferring from original FLV or video Stream (M3U8) to MP4 with the FFmpeg.Completed the design user interface independently, users can quickly operate and added validation check function.