[MPlayer-dev-eng] vf scale and yuv vs. rgb

[Sascha Sommer]

> On Fri, Apr 23, 2004 at 04:57:32PM +0200, Michael Niedermayer wrote:
> > Hi
> >
> > On Friday 23 April 2004 16:20, Sascha Sommer wrote:
> > > Some people still have problems with mplayers performance on windows.
Most
> > > of the time
> > > this is caused by video cards without yv12 support. In this case vf
scale
> > > will jump in and
> > > convert to bgr32 instead of yuy2. The problem is caused by the fact
that
> > > scale goes through
> > > its output format list and queries the vo for these video formats. In
the
> > > outfmt list rgb/bgr comes
> > > before yuv so it will always select rgb/bgr before yuv when both have
hw
> > > support (VFCAP_CSP_SUPPORTED_BY_HW). What bould be the best solution
to fix
> > > this?
> > > I propose to move the yuv formats before the bgr formats in the outfmt
> > > list. Better ideas?
> > > Michael?
> > agree
> >
> > the IMHO correct (and difficult) fix is to pass quality&speed values
around
> > and find the highest quality + const*speed path ...
>
> IMO you should just always convert to the _closest_ format that's
> supported by the output. First consideration should be same
> subsampling, second same colorspace, third same bit depth.
>

Yes, but there is still one big problem left:
Broken X, directx etc. drivers that report hardware support for various
formats while doing unoptimized softwareconversions.

Sascha