Re: xine opengl video output and high cpu load
Most likely the xine output plugin isn't very efficient. Sure opengl can do the scaling and things for 'free' but you need to get the data on the GPU. When you use traditional opengl calls texture uploads are being done synchronously. This can lead to high cpu usage because the cpu needs to wait before each upload is complete. If they would take advantage of asynchronous calls (using pixel buffer objects) the doesn't have to wait.
In other words OpenGL doesn't mean it is fast, it can be faster if the program is written in a good way.