[MPlayer-dev-eng] [PATCH] Direct3D libvo driver

[Georgi Petrov]

According to this: http://msdn.microsoft.com/en-us/library/bb172612(VS.85).aspx

I've changed D3DSWAPEFFECT_COPY to D3DSWAPEFFECT_DISCARD. The article
says that this way back buffer's contents is not defined after
Present, but we pay less speed penalty because of that. And since we
don't really need back buffer's contents after Present and my tests
show no regressions, I think this change is for the better.