Online video ad technology vendors are scrambling to get a slice of the much larger, main TV screen ad market by extending their digital buying capabilities to good ‘ol fashioned telly – and the latest to do so is TubeMogul.

The Emeryville, California-based outfit has unveiled PTV, allowing data-driven buying of TV advertising. Ad buyers can already use this “programmatic” technique on the internet, but PTV brings the same tools to bear for access to ad slots on over 80 US cable networks.

“Advertisers will enter in a demographic target along with a secondary or strategic target,” TubeMogul CEO Brett Wilson told Beet.TV in this video interview recorded at the launch. “The software is going to assemble the best mix of cable networks, broadcast networks, given day parts and days to achieve the lowest target CPM for that strategic target.”

PTV works by aggregating relationships with several providers that already offer this functionality. “We want to be the pipes for true cross-screen buys,” Wilson adds.

WSJ observes that the commonly-held view is that programmatic will not be adopted as easily in TV as it has been in display, with many powerful vested interests likely to hold on to their positions.