Unfortunately only uipmtv.org
Don't trust the schedule too much. Yesterday it was supposed to start 21:30 GMT and it started 1,5 hour earlier, so at the scheduled time it was already over. Of course they changed the scheduled time after starting the stream, so that no one can see it back right now. I think it will start about :19:30-20:00 GMT, but don't expect much - only summary of swimming, fencing and a few last rides before the only LIVE event - the combined.
Every year the stream is getting worse, thank God it's OBS which will rule Rio coverage, not the current media team of UIPM. Before London Olympics they used to show everything, after Rio there was a little bit less, but still they showed the results of riding as the riders were competing, not only after the event, and the time splits during combined. Last year it looked quite good, though the shooting range view didn't always worked good, now it's only what I wrote above. And they resigned from youtube, where you could chat with others (not only fans, but also athletes who didn't compete were writing there sometimes), now there is nothing. To be honest, for me junior competitions in Hungary are better covered than World Cups, despite having only one camera for the whole competition.