As others have said, pirate sites are something the devs are very against.
And to elaborate on the media player support, here’s this. This image is about 2 or 3 years old now, but I think this is still pretty much the case.
Whilst there is a H.264 codec available to license, it is something that would be wildly expensive for the devs:
I don’t know if there has been any updates to the Steam browser that would have fixed the issues, but at this point even if it was fixed, I doubt there is any priority for PT to reimplement it.