我从Debian官方网站建立Linphone：
$ ./linphone --version
linphone 4.1.1-655-g95245907
$ ./linphonec --version
version: 3.12.0
我在linphone尝试语音通话测试手机，但得到错误：
> call 891********8
2019-03-06 17:13:20:391 liblinphone-error-LinphoneCore has video disabled for both capture and display, but video policy is to start the call with video. This is a possible mis-use of the API. In this case, video is disabled in default LinphoneCallParams
Error from linphone_core_invite.
好吧，可能只启用设置语音？对的，这是可能的：
> help call
'call <sip-url or number> [options]' : initiate a call to the specified destination.
Options can be:
--audio-only : initiate the call without video.
--early-media : sends audio and video stream immediately when remote proposes early media.
好的选择 - 仅限音频。试试吧：
> call 891********8 --audio-only
2019-03-06 17:14:01:951 liblinphone-error-LinphoneCore has video disabled for both capture and display, but video policy is to start the call with video. This is a possible mis-use of the API. In this case, video is disabled in default LinphoneCallParams
Error from linphone_core_invite.
此选项不起作用。
问：如何在默认的LinphoneCallParams中禁用视频？怎么做？
我遇到了类似的问题，我提出的解决方案可能有所帮助。
我的问题：
linphonec> call 5201
2019-04-13 02:47:38:771 liblinphone-error-LinphoneCore has video disabled for both capture and display, but video policy is to start the call with video. This is a possible mis-use of the API. In this case, video is disabled in default LinphoneCallParams
Error from linphone_core_invite. <----- THE REAL PROBLEM
解决方案是包括域。对我来说这是：
linphonec> call sip:[email protected]
2019-04-13 02:53:00:103 liblinphone-error-LinphoneCore has video disabled for both capture and display, but video policy is to start the call with video. This is a possible mis-use of the API. In this case, video is disabled in default LinphoneCallParams
Establishing call id to sip:[email protected], assigned id 2
Call 2 to sip:[email protected] in progress.
Media streams established with sip:[email protected] for call 2 (audio).