There are standards. Windows Media Player is a de-facto standard. And ETSI has published TR 102 033 on this (attached), which is a framework for delivering DVB over IP.
There are many TV stations offering the possibility to view them via internet on Windows Media Player. If it is standardized enough to view them all via Windows Media Player it should be possible to write something universal for Linux as well. The only problem I see that the Dreambox has not enough processing power to do the video decoding in software. That limits us to MPEG-2 on the DM7025, but in the DM8000 we have MPEG-4 and Microsoft WM9 in hardware as well.
I believe most programs transmitted via internet are completely open. No digital rights management is used.
Currently the first providers of TV over IP are popping up. KPN in the Netherlands offers a service named "MIME" over ADSL, offering some 90 different TV stations. I guess they are using something based on the above ETSI framework.
I understand this is not a minor thing one could implement in a few days. However, receiving TV over IP has the possibility to become the next big thing. For Dream Multimedia it would be a good idea to be part of that.
My dream is that with a Dreambox I can watch content from different sources (DVB-S, DVB-T and DVB-IP) on a single box with a single user interface. Ideally, when watching TV one should not even know how the program gets into your house. With such a product, even your mother-in-law could watch TV via the internet.
Regards, Frits