Viacom Inc, owner of MTV Networks and Paramount movie studio, reported sharply lower fourth quarter earnings, battered by an advertising slump, poor ratings at some of its key TV networks and a softening DVD market.

Viacom's results for the quarter, which included a hefty charge, showed net profit fell to $173 million, or 28 cents a share, from $560 million, or 86 cents a share, a year earlier.

Viacom's took the restructuring charge of $454 million to account for severance, a write-down of its film inventory and other charges. The media company warned of the charge late last year, when it announced that it would cut around 7% of its workforce in an effort to counter a deteriorating ad sales market.

Adjusted earnings per share amounted to 76 cents, down from 84 cents in the year ago period, underscoring the impact of weak advertising.

Viacom, which also owns Nickelodeon and Comedy Central, said revenue was essentially flat at $4.24 billion in the quarter.