I recently watched the NTLive broadcast of Richard II at a local cinema but similar questions arise about the Dr Who 50th anniversary broadcast this evening. What is the technology behind it? I doubt if it is internet, or at least not directly: it is hard to think of anything more disturbing to a play or action film than a pause because the Internet is congested. It can't easily be transmitted beforehand and held, as both productions want to strongly restrict when the film can be played. Some sort of encrypted copy with a DRM key restricting the playing times is possible, but still opens the scheme up to piracy, either by cracking the code or recording the output as it is played for subsequent distribution. And of course any time-based restriction of the key in a simplistic way is vulnerable to someone resetting clocks as a way of breaking it. I assume the scope for selling black market copies of the RSC's Richard II is somewhat less than a sci-fi film, but quite possibly any loss of income arising is worse for a group like the RSC than a big company.

So anyone know how it is managed?