How to enable 3G video calls on Android smartphone? re.:

How to enable video calls on Android smartphone ?

In pre Android times it was easy to make video call on a standard phone, featuring small screen.

Today video call functionality is not supported by most of makes, models of Android smartphones, for unknown reason.

Ok, you need to establish 3G/ LTE data conectivity for video streaming as extra add-on- communication channel.

Ok, I have 3G data transfer enabled and still no support for making video calls.

I am not interested in third party video calling apps.

I am aware, few smartphones by Samsung support video calling functionality.

Is it due to licencing or for another reason.

If video calling was supported by default 10 years ago and promoted at Barcelona Mobile Congress, so why today video calling in Android smartphones is not supported or disabled by 99% default.

I read a lot on this subject on the Internet but all I need is to have video calling enabled in my smartphones

and I can pay extra fee.

Let me know your opinion and solution ( not interested in third party apps supporting 3G video calling)

thank you

BTW

I was told (need to test it first) that Samsung 3G video calling enabled smartphone can video call my smartphone to enable 3G video calling on-the-fly, showing camera icon to click to pick up a call.

If this is the case, so in theory, any Android smartphone can support 3G video calling ( 3G connection established and paid by third party)

BTW2

I read related questions and answers
one asked 8 years ago
Questions regarding receiving 3G calls on my IDEOS

another asked 3 years ago
How to video call

and still clear why no 3G video calling support on newer Android smartphones,
since what is claimed:
\
"
 what you are looking for is the operator backed 3G-324M solution that is available on most 3G phones (not including iPhone or Android). 
"
This article on the history and future of mobile video telephony from 2010 covers the challenges of mobile video telephony at that time.

The author lists out the then existing landscape and practical issues regarding video call adoption. Perhaps more importantly is to what the author sees in the future:


  What’s next?
  
  We do have mobile video telephony, with all of its benefits and faults. But where are we going with it? The next step will be a migration of the service from circuit switching to packet switching – to become all-IP. This will require two major changes:
  
  Migration from WCDMA/HSPA to LTE, where an all-IP network will be the norm and network capacities and bandwidths allocated for each phone will increase.
  Replacement of 3G-324M with a different standard that runs over an IP network. Probably as part of IMS (IP Muiltimedia Subsystem).
  While Apple just came out with their front facing camera and FaceTime service on the iPhone, it is still quite limited: it runs over WiFi, only between iPhone 4 devices and uses a protocol that Apple plans to open. For mobile video telephony to become a valid solution it needs to use an open standard, run everywhere and be interoperable across devices.
  
  When will that happen? At the very least 8 years from now it will require the creation of the necessary ecosystem of companies who care. The problem is that these companies are currently focused on providing the basics of the LTE infrastructure. This requires them to rethink their voice and SMS technologies in initiatives such as VoLTE (Voice over LTE).


So 


To get mobile video calling operators/carriers were mandating handsets support 3G-324M (a 3GPP specification), at least until the iPhone arrived.
Operators/carriers switched focus to providing the basics of LTE infrastructure. 
Apple hasn't opened up Facetime
Android itself has no requirement to support the 3G-324M, and Android Compatibility Definition Document shows no support beyond standard audio and video codecs so any support would have to come from manufacturers or carriers building it in themselves.
In the US, AT&amp;T and Verizon have announced end of 3G support, In Europe Vodafone has announced that 3G will be turned off throughout Europe between 2020 and 2021, and Deutsche Telekom plans to do the same in 2020 while in other regions/carriers it is still TBD.


So while older devices, like the Samsung mentioned had some type of 3G video calling support, should the associated carrier end 3G, support for 3G video calling will probably end as well, as the future lies with VoLTE which removed the circuit switch requirements.

If you are looking for older devices which does support 3G-324M,
from: https://whirlpool.net.au/wiki/android_video_calling


  The only modern smartphones known to implement 3G-324M video calling are the Samsung Galaxy range:
  
  
  Samsung Galaxy S4 +s5 +s6
  Samsung Galaxy S3
  Samsung Galaxy S2
  Samsung Galaxy Note
  Samsung Galaxy S I9000
  


Note that the most recent device that appears to have supported 3G calling on a carrier like Telstra AU is the Samsung Galaxy S5 whose last official update is Android 6.0.