[mythtv-users] Nvidia 720x480 troubles

Ian Armstrong mail01 at iarmst.co.uk
Mon Aug 9 16:47:40 EDT 2004


On Monday 09 Aug 2004 17:44, Greg Estabrooks wrote:
> > >that 720x480 is the best resolution to capture at with the Hauppauge
> > > card,
> >
> > You need to set your recording profiles to use an aspect ratio of square.
> > You will also need to set any other program you use (xine, mplayer ) to
> > use square as well.
> > You really shouldn't need to do this but nvidia can't seem to ever get
> > anything quite right.
>
>  The problem is that X's DisplayWidthMM and DisplayHeightMM
> (used in videoout_xv.cpp) are returning values that work out to be an
> aspect ratio of 1.5(4:3 with 720x480 is not) and videoutbase.cpp doesn't
> take into account situations where the source image is identical to the
> current display resolutions. As such it is forcing a resize of the video
> down to be 640x480 displayed on a 720x480 screen.

Pixel resolution has nothing to do with the aspect ratio. In PAL, 720x576 
could be either 4:3 or 16:9. You can't work out the aspect ratio just by 
looking at the number of pixels in either the width or the height. If 
DisplaySize for X is set correctly, the image should be scaled to the right 
size regardless of the actual resolution used. Both Xine & Myth honor 
DisplaySize, but MPlayer ignores it & needs a command line option to set it. 

-- 
Ian


More information about the mythtv-users mailing list