Video ads within online TV programming is great for brand awareness but repetition is watering that awareness down, according to a new study from MillwardBrown, reports ClickZ.

The study comes as more TV networks are putting their programming online and shows that advertising within those shows leads to higher brand recall. Participants had 82 percent brand recall with online viewing compared with 54 percent on TV.

The percentage of those who correctly linked an ad to a brand also was higher, 93 percent online compared with 70 percent on TV. Part of that could be because when watching TV people are usually doing something else. Online, though, people are paying more singular attention to what they're watching.

One potential problem, though, is that the same ad is often shown several times during the same show. That can lead to viewer frustration. Though only 15 percent of TV watchers said they were tired of seeing an ad repeatedly, 28 percent of online viewers said it frustrated them.