Microsoft has put its talks with media companies about an online subscription service for TV shows and movies on hold, according to people familiar with the discussions. The company had been in intense talks with potential programming partners for over a year and was hoping to roll out the service in the next few months. But it pulled back after deciding that the licensing costs were too high for the business model Microsoft envisaged, the sources said.  Microsoft is still working to distribute TV shows over the Web, focusing on delivering programming via its Xbox gaming system to existing cable subscribers.