[by:www.51voa.com] [00:00.00]¸ü¶àÌýÁ¦Çë·ÃÎÊ51VOA.COM [00:01.96]Last week, Google launched Duo, a new video calling app. [00:07.56]It was first announced in May this year. [00:11.44]Duo means "two." As its name suggests, [00:17.40]Duo allows two callers to connect on an Android or iOS device. [00:26.16]Duo is easy to use and does not require knowing someone else's user name. [00:32.20]Video calls can be placed simply with phone numbers. [00:37.36]But Duo does require users to download an app. [00:42.56]And it enters a crowded field of video calling services, [00:47.56]including Skype, FaceTime, Messenger and Hangouts. [00:53.68]Choosing a service Choosing a video calling service can be difficult [00:58.56]because the services have different features. [01:02.08]The key is learning what features are important for what situations. [01:08.51]Some people use more than one video calling service. [01:13.72]For example, they may use one service with friends and another for business. [01:21.08]Fortunately, all these services are free, [01:26.08]so users can try them without spending any money. [01:31.00]Here are some things to consider when choosing a service: [01:36.32]1) Adding an app [01:38.64]Many of these services do not work [01:41.84]unless you download a separate app for them. [01:45.20]If your friends don't already have a video calling app, [01:49.76]they may be unwilling or unable to download a new one. [01:56.00]2) Signing up for an account [02:00.40]Similarly, if you don't want to sign up [02:03.60]for a new account to use a video chat service, [02:07.56]you may want one that works without needing a new account. [02:11.76]For example, FaceTime is built into Mac computers, iPhones and iPads. [02:19.72]No additional app is necessary. [02:23.84]And because many people already are on Facebook, [02:28.44]they can use Messenger for video calls without downloading a new app. [02:34.04]3) Voice calls [02:36.80]Some services also offer voice calls. [02:41.48]For example, FaceTime, Messenger and Skype [02:46.64]allow users to make voice as well as video calls. [02:51.28]Skype offers voice calls to other Skype accounts for free [02:56.32]and to phone numbers for a fee. [02:59.76]FaceTime lets users call iPhone phone numbers around the world for free. [03:07.04]4) Platforms [03:09.56]The more platforms a video calling service can work on the better. [03:15.48]Duo, Skype, Messenger and Hangouts all offer apps across platforms. [03:23.84]They can be used on both Android and iOS devices, such as iPhone and iPad. [03:32.12]FaceTime is for Apple devices only ¨Cincluding Mac, iPhone and iPad. [03:40.28]5) Computer [03:43.72]Many video calling services can be used on computers as well as on mobile devices. [03:51.96]FaceTime, Messenger, Skype and Hangouts [03:56.76]all let users make video calls using a computer, phone and tablet. [04:02.92]Users do need to have a video camera on their computers to use these services. [04:10.08]Duo is not available for computers. [04:15.08]6) Ease of use [04:17.52]Duo and FaceTime are the easiest services to use. [04:23.40]Calls can easily be answered, [04:25.76]and users can switch between the front and rear cameras on a phone. [04:31.44]7) Connecting with others [04:34.92]Connecting with others should be simple. [04:39.00]Skype users must know a friend's user name before placing a video call on Skype. [04:46.52]But Duo and FaceTime users need only a friend's phone number to place a video call. [04:53.92]Messenger lets users make video calls to their Facebook friends. [04:58.52]And Hangouts users can place calls with their friends' Gmail addresses or on Google Plus. [05:07.28]8) Multiple users [05:09.96]Some video calling services let users have group chats [05:15.08]with multiple people joining the call at the same time. [05:20.16]Hangouts, Skype and Messenger let users add multiple people to the call. [05:27.24]Duo and FaceTime allow users to connect only two callers. [05:33.52]9) Screen sharing [05:36.80]Screen sharing allows users to display their computer screens [05:41.32]in the video call instead of the image from the camera. [05:45.80]This feature is useful to demonstrate something [05:50.00]or to get help solving a computer issue. [05:54.28]Hangouts and Skype allow screen sharing. [05:58.20]This chart sets out the different features for each service. [06:03.32]Duo is available as an app on: [06:06.36]Duo for Android [06:07.96]or Duo for iOS [06:11.48]Duo has a feature called Knock Knock [06:14.76]that shows video from the caller before the user answers the call. [06:20.52]Knock Knock works only on iOS when the Duo app is open. [06:25.48]The app will also lower the quality of the video [06:30.72]if the Internet signal strength is weak. [06:34.52]This video shows how Duo works. [06:38.52]Because Duo is new this month, [06:41.59]users will probably have to ask friends to add the app [06:45.64]in order to connect with the service. [06:48.64]FaceTime lets users of Apple products connect via video and voice calls. [06:55.44]The service is easy to use and available on iPhone, iPad and Mac computers. [07:02.64]Users can connect with others using cell phone numbers or email addresses. Skype [07:08.28]Skype is Microsoft's video chat service. [07:12.80]Users can also make voice calls on Skype. [07:16.52]Skype calls can be made using a computer or mobile device. [07:22.04]People then use screen sharing to see each other's screens during a video call. [07:28.60]Up to 25 people can be added to a group Skype call. [07:33.20]Skype also offers voice messages and other features. [07:38.80]Facebook's video calling service, Messenger, [07:42.68]is available on computers in chat using Chrome, [07:46.96]Firefox and Opera browsers, but not on Safari. [07:51.96]It also works on mobile devices in the Messenger app. [07:57.52]Users click on the camera icon to begin a video chat with a Facebook friend. [08:03.92]In April, Messenger was updated to allow group chats. Hangouts [08:09.80]Google's other video calling service is Hangouts, [08:14.16]which is available on computers and mobile devices using the Hangouts app. [08:20.00]Users can add multiple people to the video chat [08:24.64]and share their computer screens. [08:27.28]I'm Jill Robbins.