[mythtv-users] improve upscaling quality?

[Gordon McLellan]

On Wed, Apr 22, 2009 at 11:34 AM, Mark Buechler <mark.buechler at gmail.com> wrote:
>
> Maybe someone will enable ffmpeg's software scaling in MythTV someday.
>
> - Mark.

I've experimented with playing SD recordings back under the mythvideo
interface, where I can use mplayer and the lancosz scaler:

mplayer -fs -zoom -vo vdpau -vf crop=720:380,aspect=16/9 -sws 9  #crop
only needed if playing back 16:9 content that was recorded in
letterboxed 4:3 format.

Putting -sws 9 into the command line for mythdvd yields excellent results too.

It still doesn't look as good as the TV's native DSP but it looks a
_lot_ better than the default upscale which xorg (or myth) is using.
For all I know, this could be a limitation of the analog capture
hardware - perhaps the pvr-500's ADC is dropping too much data.
Perhaps I need to fiddle with the encoding bitrate, which is at
4400-6000 kbps right now.

I've tried to get the video card to output at a lower resolution when
playing low-res content, but no luck there (Disabled Composite,
Disabled GPU scaling, Disabled auto-res).  Xorg even thinks it has
changed resolutions (as indicated in a verbose log), yet the output
remains at 1920x1080.  That is with a geforce 8400 and the latest
nvidia driver I could find.  Another oddity is when my PC boots, the
TV is set to a 720x480 video mode, however, trying to achieve that
mode under Xorg results in a "Unsupported" message from the TV.
Setting 720x480 under Windows works just fine.

-Gordon