I am making a short film to enter it into a contest. The contest is very small and there is no prize and there won’t be much attention on it. In fact the submissions have to be a minute long. Anyway, they don’t want to screen anything that might infringe copyright so I need to know what is okay and what is not. I am using the video and no sound. How can I get this kind of information from Valve? I mean, is it possible to get something from Valve stating what they see as legitimate and not infringing on copyright?