Maximum number of people and video display in a web browser

When you say that the maximum number of participants is 1000, does that mean that up to 1000 people can participate at the same time in a web browser?

Also, is it correct that the maximum number of videos that can be displayed on the screen simultaneously in a supported browser such as chrome is 9?

I have checked this forum, but would like to see how it performs in a web browser.