Ken Harrenstien, a Google software engineer who is deaf, said the hundreds of thousands of captioned videos on YouTube and Google Video suggest that more people are becoming aware of how useful captions can be.

"As we've explained in the past, captions not only help the deaf and hearing-impaired, but with machine translation they also enable people around the world to access video content in any of 51 languages," Harrenstien said. "Captions can also improve search and even enable users to jump to the exact parts of the videos they're looking for."

Encouraging Uploaders to Caption

In addition to automatic captions, YouTube is also launching automatic caption timing, or auto-timing, to make it significantly easier to create captions manually. With auto-timing, video uploaders no longer need to have special expertise to create captions in YouTube. Harrenstien hopes this technology encourages more members to caption their videos.

Here's how it works: Create a text file with all the words in the video, then upload the file and Google's automatic speech-recognition technology figures out when the words are spoken and creates captions for the video. As Harrenstien sees it, the process should significantly lower the barriers for video owners who want to add captions, but who don't have the time or resources to create professional caption tracks.

YouTube visitors should expect to see both new features in English by the end of the week. For the initial launch, auto-caps are only visible on a handful of YouTube partner channels. But auto-timing is rolling out globally for all English-language videos on YouTube.

Is It Accurate Enough?

Greg Sterling, principal analyst at Sterling Market Intelligence, commended Google for taking steps to make videos more accessible to deaf and hearing-impaired people, and pointed to another worthy use of Google's automatic speech-recognition technology. But there may be issues with the captions.

"Google Voice can be accurate, but the accuracy ratings are not at the level they need to be for captioning," Sterling said. "Maybe this is going to help Google fine-tune its technology. But you don't want to show a news clip with an inaccurate caption that's cockeyed. That would be embarrassing for Google."

Although Google admits the captions won't always be perfect, the company believes they can still be helpful and the technology will continue to improve. "Today I'm more hopeful than ever that we'll achieve our long-term goal of making videos universally accessible," Harrenstien said. "Even with its flaws, I see the addition of automatic captioning as a huge step forward."