For me the first thing that comes to mind for "multimedia Swiss army knife" is ffmpeg. I think that right keywords here are "web", "media" and "download" (altho

For me the first thing that comes to mind for "multimedia Swiss army knife" is ffmpeg. I think that right keywords here are "web", "media" and "download" (although it can do things other than downloading, like extracting stream URLs or just querying available formats).