Cast audio+video during video call

**Is your feature request related to a problem? Please describe.**
When I do video call, I like to cast it to my smart TV. When I do it, the video is cast but not the sound. The sound is working but comes through my phone instead of the TV. I have no problem casting sound+video with youtube.

**Describe the solution you'd like**
Having the sound cast to my smart TV during video call.

**Describe alternatives you've considered**
It looks like other apps have this problem too.

**Additional context**
I found this thread about the same problem but with zoom on the [chromecast forum](https://support.google.com/chromecast/thread/41716778?hl=en). It looks like the problem is the app goes with the speaker with a mic. Since my smart TV does not have a mic, the sound is output to my phone.
Could it be possible to separate microphone and sound to select any available speaker? Or is it an android limitation?

No files, tests, or entry points are named. Start by investigating the Android video-call audio route and Chromecast behavior described in the issue, including whether microphone and speaker outputs can be separated. Done means audio and video from a call are routed to the TV, or the Android limitation is documented if that is not possible.

Written by the indexing model from the issue text.