Yahoo plays catch-up in messaging with app that enables video calls _ without the sound

Imagine making a video call without other people being able to listen in.

Yahoo is trying to make that happen with Livetext, a new app that seeks to make video calling as private as texting.

Yahoo says video calls can be better than texts for expressing emotions, but their audio component makes private conversations public. With Livetext, you message friends by typing, just like texting, but you see video of friends without the audio.

It's the latest example of Yahoo trying to catch up in mobile since Marissa Mayer became the company's CEO three years ago. Facebook Messenger, WhatsApp, Skype and other services already deliver video calls. Yahoo's twist is silencing audio.

The app will be released Thursday for Apple and Android devices.