Google has announced a number of mobile ad offerings for game developers at GDC.

The first is an expansion of its Trial Run Ad format, which let users stream an advertised game direct from the ad before downloading, to appear within search results.

Snappily named Search Trial Run Ads, these only appear to users connected via wi-fi, and allow for up to 10 minutes of play when the user hits the Try Now button. The ads are currently in a closed beta, and available to selected advertisers in the US.

Its also introducing portrait video ads, which will show full-screen to users who arent holding their device on its side. According to Google, over 80 per cent of video ad views in mobile apps on the Google Display Network are from devices held vertically, and portrait videos have seen significant improvement in both click-through and conversion rates from game developers.

AdWords, meanwhile, is gaining Active User Targeting for Games. This new type of targeting for Android apps reaches users who have spent more than 30 minutes playing games, or who have played a Google Play Games integrated game, in the last 30 days.

Finally, rewarded video ads – which offer users in-app freebies in exchange for engaging – will be available in AdMob Mediation, from a number of ad providers including AdColony, AppLovin, Chartboost, Fyber, Upsight, and Vungle.