If you watch videos via proxy server, e.g. from YouTube at school, you need to use video streaming proxy server. Ordinary proxy servers that work well with browsing, might fail to stream video, especially if the connection speed is not very high.
The problem is in the way how the video is played via the proxy server. A video player requests a chunk of video, usually many hundred KiloBytes in size. An ordinary proxy server first fully downloads this request from the content server, and only then sends it further to the video player.
This logic works well for the case of normal browsing. But for video, the total delay in the delivery of a requested chunk of video to the video player, often can make a big difference. If the video player finishes playing the previous chunk before the next is downloaded in full, video player will stop and wait.
Video Streaming Proxy Server, on the contrary, won’t wait for the chunk to download, but will start sending smaller chunks to the video player. So that the video is not interrupted by waiting.
You-proxy.net software is a video streaming proxy server.