Embedded Windows Media Player loaded in QtWebKit: set volume does not work

when loading this html (html is also here) in the 开发者_如何学运维Qt 4.6 Demo Browser,

pressing "Set Volume = 80" fails without raising an exception.

Notes:

The same html works fine in Chrome and Firefox.

Happens on Windows, but works fine on Mac.

Fails also with Qt 4.7 Beta Demo, and in Arora browser.

Any idea?

It is a bug in QtWebKit's treatment of calls to NPAPI plugin: Int32 is treated as double.
I put a patch to fix this.
Replace the contents of the file:
\Qt\2010.02.1\qt\src\3rdparty\webkit\WebCore\bridge\c\c_utility.cpp
by this.