Pretty sure literally all of them do, but generally only full duplex.
Not triplex or quadruplex etc.
In other words, if you're having a 1-1 video call, both of you have your audio working at all times.
But as you go to 3, 4, 5, 10, 20 participants, it generally continues to be just max 2 simultaneous audio streams, determined by whoever has been the loudest recently.
Unless you turn on special features like music mode etc.
This is a feature, not a bug, because otherwise background noise and sounds would start adding up to become intolerable. (Why we usually try to intentionally stay on mute anyways, so we don't accidentally become even just that second audio stream.)
Last N audio with N about 3 is pretty common. That might be you and three others, or three speakers including you. Beyond that isn't very common, because a) it's not very useful, and b) Google's WebRTC software (which is commonly embedded elsewhere) would only decode three audio streams anyway.
Not triplex or quadruplex etc.
In other words, if you're having a 1-1 video call, both of you have your audio working at all times.
But as you go to 3, 4, 5, 10, 20 participants, it generally continues to be just max 2 simultaneous audio streams, determined by whoever has been the loudest recently.
Unless you turn on special features like music mode etc.
This is a feature, not a bug, because otherwise background noise and sounds would start adding up to become intolerable. (Why we usually try to intentionally stay on mute anyways, so we don't accidentally become even just that second audio stream.)