Youtube is the representative of Web 2.0, it has so many videos, updates frequently, many people have put the above videos in their blogs, so why do you want to convert it? The video downloaded directly from Youtube is flv format, for some websites that do not support flv upload, but also convert it again, and install some software, some people may feel troublesome, in fact, make good use of some online services, we can also achieve a one-time conversion and download.