In case I make a voice chat, the hangout video feature is closed and only audio feature isused.
However, I checked it with Google support below, but it is not clearly marked, so
I have a question.
Hangouts is free in the U.S. and Canada and offers low international rates, so you can make voice calls, send text messages, and even have group video chats from your mobile device or computer without paying a dime.
As you have problem for a video call, you might need to turn on permissions for your camera and microphone in your computer's settings.
Otherwise check out everything is OK before starting a real video call.
1. Check Hangouts system requirements.
2. Connect a camera, microphone, and speakers with the latest software to your computer.
3. When asked to use your computer's camera and microphone, click Allow.
4. Download and install the latest version of the Hangouts plugin for Internet Explorer.