Variety: Can a TV network wring more value from TV commercials if it runs fewer of them? Viacom is about to find out. The company, which owns MTV, Nickelodeon and Comedy Central and has suffered significant ratings declines in recent months, will in October begin to run fewer minutes of commercials in prime time on all of its networks. Where Viacom has been running between 17 and 18 minutes of ads per hour, it will now try to run between 14 and 15 minutes.