Verizon is promising crystal clear VoLTE calls nationwide "in the coming weeks." Verizon says VoLTE will simplify video calls.

In a post on the carrier's website, Verizon said that "in the coming weeks, Verizon Wireless customers can begin to see what Advanced Calling 1.0 -- HD Voice and Video Calling -- can mean to their wireless experience when tightly integrated with their 4G LTE smartphones."

Verizon is placing on spotlight on the video aspect of VoLTE, saying that those calls are actually simplified when using VoLTE. The interface for video calls includes a contact list and easy controls to start and end the video portion of the VoLTE call. 

While AT&T and T-Mobile have both announced VoLTE deployments, Verizon acknowledged that HD Voice and Video Calling work only when both people are in the Verizon 4G LTE coverage area and are using VoLTE-enabled smartphones from Verizon.  

Verizon didn't specify which VoLTE-enabled device it will initiall offer with the service. 

T-Mobile has already claimed a nationwide VoLTE rollout, saying that 2.8 million VoLTE-capable devices are currently running on its network and that more than 52 million VoLTE calls to date have been placed. 

AT&T meanwhile, has launched in select markets in Illinois, Indiana, Minnesota and Wisconsin, and will continue to expand on a market-by-market basis.

AT&T launched with a limited number of devices that support the feature, including the Samsung Galaxy S4 Mini, which according to AT&T will be "coming soon." Additional devices are slated for market in the near future.