This topic was already discussed in the forum a while ago. Did you search before posting? I guess you didn't...

It should not be a feature request as it does not concern vMix software development, it's not a missing feature in vMix, it's just a way of using it so that's your responsability.

It's potentially possible if your remote guests are shot in front of a green screen. However green screen keying requires a very high quality image source to work well. Best is to use uncompressed signal, 10 bit has better results than 8 bit, the better the camera, the better the keying, everything must be very sharp and precise and very well lit if you want good results. Doing chroma keying in a live production is even more demanding than in post-production 'cos settings can't be adjusted for each segment...

vMix Call being basically a H.264 encoded feed transmitted over the internet with an extremely high compression and low bitrate, in 8 bits and 4:2:0 subsampling, you understand easily that it technically can work (it's just a matter of doing it) but will give very poor results due to the nature of the source. You might have "acceptable" results with bald people for example but as soon as your guests have hair (especially long or curly) or depending on their clothes, the keying will be terribly bad... I don't know your standards or expectations, it might be good for you anyway, but for me it's just crap and I don't want my name on such a thing.

Just try and you'll know...

Guillaume

This is pure math. The better and more granular information you have of a picture the better you can apply filters. So 10 bit 4:2:2 workflow would theoretically enable better experiences. 4:4:4 would top that also. For a file based workflow BMD has announced a new raw format. Could be interesting to see support for that.