YouTube is a huge library of video resources, but for most people in the country, the connection speed is very problematic, the turtle speed buffer will be disappointing, if you can download it, you don't have to endure a long wait. In addition, many videos are also very collectible value,YouTube will not let a video permanently remain on its server, even if the money has no place to make Google also can not withstand the world's video lovers to YouTube server bombing it. The good news is that we have many tools that can download videos from YouTube and convert them to a format that can be played on your handheld device. It is difficult to choose the best of these tools, and they are all well worth trying. The following provides 23 methods, classified by work platform: