Devices such as smartphones, tablets and games consoles accounted for 12% of all online video ad viewing in Q4 2012, an increase from just 2% year-on-year.

Apple continues to dominate non-desktop video viewing, with 60% of viewing taking place on iPhones, iPads and iPods.

In comparison, Android devices make up 31% of non-desktop viewing, though it’s held back the by the iPad’s dominance of the tablet market.

The data come from FreeWheel’s Video Monetisation Report, which also shows that online video viewing increased by 23% from Q4 2011 to Q4 2012.

This has coincided with a massive 49% increase in the number of online video ad views in the same period, which is partly due to the number of ads being crammed into each online video.

For example, the number of ads shown per video view in long-form content (20+ minutes) has increased from 6.9 in Q4 2011 to 9.4 in Q4 2012.

The average for short-form content (shorter than five minutes) has also increased to 0.66 from 0.54 a year ago.

Perhaps surprisingly, ad completion rates are also on the rise. The report shows that ad completion rates for long-form content increased from 88% to 93% year-on-year.

The increased popularity of long-form content online is well documented, with stats from Ooyala showing that the majority of video watched online is now longer than 10 minutes.

Interestingly, the report also suggests that TV best practices are becoming more common online.

Throughout 2012, 30-second video ads have become increasingly common and now account for 42% of all online video ads.

In the same period, the proportion of video ads that are 15-seconds long has decreased from 45% to 34%.

FreeWheel suggests that this is due to the fact that content owners and advertisers have realised that consumers are willing to watch through longer 30-second ads, so there is no need to produce separate 15-second ads for online channels.

The data in FreeWheel’s report comprises almost 15bn video views and over 13.5bn video ad views during Q4 2012.