Add Wells Fargo Securities’ Marci Ryvicker to the list of analysts who believe that Viacom shares have hit bottom after a year of dreary results — especially at its two flagship channels, Nickelodeon and MTV. Ryvicker upgraded Viacom this morning to “outperform” from “market perform” although she didn’t change her financial targets. The stock just recently recovered from the drubbing it took last September as it became clear that Viacom had big ratings problems. The target demo audience for Nickelodeon is -25.7% since then, while at MTV it’s -9.3%. But in about six weeks, comparisons with last year’s ratings and ad sales will “start to ease,” Ryvicker says. That’s “likely to be a catalyst for the stock, particularly as [Viacom] heads right into its financially significant period known as the ‘Hard 8′” — the eight weeks before the holiday shopping season when Nickelodeon makes most of its ad sales. She also believes that in the recent upfront ad sales season, Viacom made “conservative audience guarantees, which means fewer makegoods and better monetization in the upcoming scatter market.” On top of that, she’s encouraged about the new contract terms with DirecTV. Ryvicker expects to see a turnaround at Paramount with upcoming films including G.I. Joe: Retaliation, Star Trek 2, and World War Z. She adds, though, that the studio only accounts for 8% of Viacom’s operating income so it is “unlikely to materially move the needle.” Viacom shares are up 4.8% since the end of last August, and are +10% so far in 2012.