double PBO ? or simple ?

In order to stream video, I use PBO. But when I have one media 1920x1080 25fps and another 1280x1024 50fps, I have a lot of drops … Is it better to use a double buffer PBO to improve performance ? Can I use safely a Multithread double PBO, (copy data in one thread calling wglmakecurrent()) and display the texture in another. Is it a good idee or there will be to much loose in performance by switching between shader context.