Twitter's plan to boost revenue from video advertising seems to take longer than expected. The company said Tuesday that third-quarter sales will be much lower than analysts predicted, in part because ad dollars from videos won’t have kicked in yet.

It will take time to "unlock" video ad budgets because the company hasn’t finished building the technology advertisers need, Twitter said. The company still has to develop an accurate way to verify who saw video ads, along with tools that help advertisers pick audiences and time their campaigns.

Twitter has struggled to grow advertiser budgets for its social media ads. Twitter’s existing ads are priced higher than some rivals’ ads, and that has proven to be a headwind for efforts to increase Twitter’s share of social media marketing budgets.

The company's second quarter revenue missed estimates and the revenue forecast for the current quarter of $590 million to $610 million was well below the average analyst estimate of $678.18 million.

Twitter's user base increased about 1 percent to 313 million average monthly active users in the second quarter from 310 million in the first quarter.