Authorization and mp4 file editor/joiner

I need you to develop some software for me. I would like this software to be developed for Windows. First: the app has to start an authorization screen (email and password webservice call) - there is an api which can authorize the user and give back the authorization status. If the user is authorized: Second: the application has to create a list (based on the result of a webservice call - json formatted) - (these list are video playlist titles) Third: if the user pick a playlist from the above mentioned list, the application should create the playlist into a physical file. Playlist info: every playlist has multiple video clips joon together. On our server there are mp4 video files (these ar uncutted videos). A playlist contains the url of these mp4 files and contains information about the video clip parts. For example: the video url: [login to view URL], the clip infos: [login to view URL] (from: 4sec - to: 16sec) [login to view URL] (from: 46sec - to: 56sec) The final result should be ONE join video with these clips above, from the basic video. Other infos: there could be more than one mp4 video, and unlimited clip items.