Video call preview (using Grandstream GXV3275 Android IP Phone)

Hello everyone,

I just started using FreePBX and the overall configuration went fine, except for one small issue: I cannot get a video stream preview of a call before I accept the call.

My setup :
Grandstream GDX3710 video doorbell and GXV3275 IP videophone.
I am using FreePBX on a RPi. Both devices are registered on the server and I enabled video calls on the admin.

Video calls work fine: I can see the video stream once I answer/make a call.

But the videophone also comes with a preview option: when the doorbell is calling, it automatically shows the video feed before the user answers the call. Yet I cannot make it work with the SIP server: all I get is a black screen until I accept the call and see the video.

On the phone’s user guide, the preview function is documented as follows:
Enables the preview feature for the incoming video calls. Defines the
function for the incoming video call. If it is set to “Preview”, the phone
system will pop up the PREVIEW key on the LCD screen when there is an
incoming video call, and users could tap on it to check video caller without
answering the incoming video call (the call will keep playing ringback on
the caller side). The default setting is “None”.
Note: By pressing the preview button, the phone will send the SIP 183
message to the caller’s camera, based on SIP RFC3261; the caller’s
camera should start sending the stream to the phone upon receiving the
SIP 183.
At any time, the GXV32xx user can press the “Answer” button. If done then
the phone will send the SIP 200OK and call will be fully established.

Any suggestions to make it work?

Thank you,

Maybe that function is only supposed to work when used in conjuction with a Grandstream PBX.

I recall reading about another feature of the video door phone, to send pictures to a grandstream with lcd but not video compatible, like GXP2160, that can be made to work if you modify the header to include the expected data, as the Grandstream PBX does.

Maybe the preview function is something similar, but you might need to contact Grandstream support, they will be able to provide more information.

Hi Ariel,

Thank you for your answer.
I just contacted Grandstream about the issue and they told me “the server needs to support early video media through the 183 response.”

Does FreePBX/Asterisk supports early video media?

Thank you,

Asterisk supports early media, but you should ask the FreePBX guys if some special configuration is needed.

Maybe Grandstream can provide an example of the dialplan that they use on their PBX, as those run on Asterisk.

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