[Freeswitch-users] A primitive way of getting VoLTE recordings in FreeSwitch. Looking for better ideas.

[Oivvio Polite]

I'm building a call recording tool (outgoing calls only) where the prime considerations are 1) audio quality  and 2) ease of use.

During the last years many mobile carriers have enabled VoLTE calling
that operate at higher bitrates with better audio quality than
traditional telephony.

A common patterns seems to be that VoLTE is only enabled when the phone
handsets on both ends supports it and both parties are on the same
mobile carrier.

To get that sweet HD audio in my call recordings I can't just run
FreeSwitch with a regular SIP trunking provider. I've googled
extensively and can't find any SIP trunking provider that claims VoLTE
capability.

A primitive way recording VoLTE calls with FreeSwitch would be to cook
something together with mod_portaudio kind of like this:

The user dials into FreeSwitch with a some custom HD audio client,
probably using WebRTC. We capture this call leg at the server. Hooked up
to the FreeSwitch box we have 3 audio cards. Connected to each audio card is a
VoLTE capable cellphone on a diffrent mobile carrier (We pick the three
most popular). The phones connect via the cellphone jacks. Each phone is
also running a custom app that listens (via Wifi) for instructions from our FreeSwitch box.

When the call arrives to FreeSwitch we check what carrier the the user
is dialing. Hopefully one of our 3 connected phones also use that
carrier. If so when instruct that phone to call the destination number
and we connect the phone via mod_portaudio as the second leg of our
call.

This scheme as kind of Rube Goldberg and has many limitation.

1. If we want to support simultaneous calls on the same carrier we need
more phones.

2. We loose audio quality in the recording when going from digital to
analog.

3. Cellphones error prone, subject to freezes and what not. This is not
something you want to put in a datacenter.


So I'm wondering what other options might be for recording VoLTE calls.


kind regards, Oivvio Polite