[mythtv-users] 50Hz PAL over 60Hz VGA (again x2) - OpenGL Video Renderer? Custom resolutions for playback?

Ben Lancaster lists at benlancaster.co.uk
Mon Jun 11 09:57:26 UTC 2007


Hi all,

I'm one of the unfortunate ones using a Samsung LCDTV over VGA @ 60Hz  
to play a 25/50Hz PAL source (DVB-T), and getting quite annoying  
frame jitter from the deinterlacer duplicating frames. Solutions  
discussed thus far:

1) Switch to DVI/HDMI - not an option for me; my TV doesn't have HDMI

2) Get a graphics card with component out and use that -  
unfortunately, it seems that the refresh rate on nVidia cards is  
hardware-locked to 60Hz for component out

3) Use a modeline that has a refresh rate that's a multiple of 25 -  
this looks most promising. My TV supports 1024x768 @ 75Hz (native  
resolution is 1280x720/1360x768), so with Kernel deint I do get a  
much better picture, however since my TV is 16:9, the UI etc are all  
stretched to fit; not ideal. I came accross the different resolutions  
for playback setting, but noticed that I couldn't set arbitrary  
resolutions in there, only standard TV resolutions - is there any way  
to add custom resolutions, namely 1024x768 at 75Hz?

The other thing that looks promising is using the new OpenGL video  
renderer mentioned here - http://cvs.mythtv.org/trac/ticket/2649

Specifically:

> Quality of the progressive scan deinterlacers is pretty good. They  
> cope very well with low to moderate movement but less well with  
> fast motion. (Also seem to handle frame rate discrepancies better  
> than bobdeint - eg PAL at 60Hz)

and:

> TODO: Framerate conversions e.g. PAL to NTSC rates


I tried adding the "UseOpenglVideo=1" switch to my mythfrontend  
command, but it seems to have no effect - I'm using latest mythtv- 
trunk RPMS from atrpms-bleeding; I'm guessing that it's because this  
hasn't made it in to SVN yet? Does anybody have any news on whether  
this is in trunk, and how to use it? I have an nVidia 6200 card, so  
from what the post says my hardware should cope with it OK.

Thanks,

Ben


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