Why can't I stream YouTube through Firefox?

JP just bought a new computer workstation, but Firefox no longer streams live via YouTube. Leo says that it could be that there isn't support for HTML 5 because there's no standard for streaming video. The browser gets to decide what codec to use and Firefox might not support that codec since it may be proprietary. Leo recommends trying Google Chrome.

The chatroom says that JP may have IGPU enabled in his BIOS. Disabling it should free it up. Here's a video on YouTube about it.