When I open https://www.cbsnews.com/live/ to live stream CBS News, I found the CPU usage is nearly 100% and there are about 50 threads running at the same time for this process. You can find the URL address of the video source by checking the source code of the webpage. In my case, the video URL is something like the following, and open it in the browser.
https://dai.google.com/linear/hls/p/event/(SOME ID)/stream/(SOME ID):MRN/variant/(SOME ID)/bandwidth/3009600.m3u8
One additional benefit of directly using the video URL is, in Safari, it enables “Picture in Picture”.