• by Gavin O'Malley  @mp_gavin, January 17, 2012

After an unexpected dip in November, domestic online video viewership regained its footing in December, according to new data from comScore.

Last month, the measurement firm recorded over 43 billion videos views -- breaking the standing record of 42.6 billion views in October. (It declined to 40.9 billion views in November.) 

However, the total U.S. video viewing audience continued its decline from 183 million in November -- and 184 million in October -- to 182 million in December.

Making up the difference, average viewers watched 23.2 hours of video in December -- up from an average of 20.5 hours in November, and 21.1 hours in October.

Last month, the duration of the average online content video was 5.8 minutes, while the average online video ad was 0.4 minutes, according to comScore.

Video ads accounted for 14.1% of all videos viewed, and 1.2% of all minutes spent viewing video online.

As usual, Google and YouTube dominated all online video properties with 157.2 million unique viewers in December, followed by Vevo with 53.7 million. Yahoo sites ranked third with 53.3 million viewers, followed by Viacom Digital with 45.8 million, and Facebook.com with 42 million views.

Through the month, the average video viewer spent 7.9 hours on Google sites, and 3 hours on Hulu.

Hulu generated the highest number of video ad impressions at nearly 1.5 billion, followed by Adap.tv in second place with 1.1 billion. Tremor Video ranked third with 942 million, followed by BrightRoll Video Network with 872 million and Specific Media with 496 million. 

In December, time spent watching video ads totaled more than 3 billion minutes during the month, with Adap.tv delivering the highest duration of video ads at 636 million minutes.

All told, video ads reached 51% of the total U.S. population an average of 46 times during the month, while Hulu delivered the highest frequency of video ads to its viewers with an average of 46.

Top YouTube partner sites data included video music channel Vevo -- with 53.5 million viewers -- and Warner Music, with 31.7 million viewers. 

Gaming channel Machinima ranked third with 22.7 million viewers; followed by Maker Studios with 10.4 million; FullScreen with 9.7 million and Big Frame with 8.3 million.