^^^^ the problem with Rio is not the danger and crime. I lived there many years and can say that. Of course, some places are very dangerous, but that's more to the north of the city.
Just keep a low profile, dress very casually, an old shirt, old flip-flops, etc. Don't hang that expensive camera around your neck, as I've seen many German tourists do.
As for favelas, they're mostly safe, even more now that the police has begun a military type occupation. It's a program called "UPP (Unidade de Polícia Pacificadora)". All drug dealers left.
Note: while in power drug dealers were maintaining law and order in favelas and surrounding areas by punishing petty thieves and criminals. Even then it was pretty safe. Now that they're gone, some problems appeared that police cannot deal with. But that's another topic.
What bothered me most in Rio was the filth: taxi drivers urinating in "Aterro do Flamengo" (a famous avenue that connects the Santos Dummont airport to Copacabana), litter everywhere, the beaches had garbage all over the sand, the water is dirty, sewers dumping in the beaches, etc.
People are pigs over there, that's a fact.
But it's a nice city to visit for one week or two, three weeks the most.
Note: it's Rocinha, not Rochina.
