Comment # 3 on bug 1102793 from Neil Rickert

I have now restarted firefox.  And twitter videos do not play.

Previously they played in firefox but not in chromium or opera.  Now they do
not play anywhere, as far as I can tell.  They still won't play in firefox or
opera.  I have not checked vivaldi, but they probably won't play there either.

Marking this bug as confirmed.