This is Yealink's response
The Vodia PBX is not sending Video to the T58A in the original INVITE. This is not a setting that can be changed on the phone.
You will want to look to enable sending Video on the PBX side, or look into sending a direct SIP call to the Video phone, from the door phone (if possible).
The reason the phone being placed on hold, then starts the video, is because the phone sends a new INVITE when it comes off of hold. The phone is telling the PBX it has the option to send and accept video, so then the connection is made for video between the two devices.
You need the PBX side to send the initial INVITE SIP/SDP packet with the Video option included. There is no programmable button solution for this.
Will something be built in the PBX to allow this in the future?