[mythtv-users] VGA verses HDMI

Kevin Ross kevin at familyross.net
Thu Sep 30 18:58:01 UTC 2010


  On 09/30/2010 09:59 AM, Simon Hobson wrote:
> Wade Maxfield wrote:
>
>> I can't personally confirm this, but Dan Benjamin (from 5by5 TV) said 
>> that on Samsung TVs if you connect your PC to the first HDMI port and 
>> name the port PC, it should disable overscan.
>
> I have an LE26B350 (26" LCD) and one of the ports is labelled 
> HDMI1/DVI I connected a computer to it (Scaleo E media centre) and it 
> automatically detected it as a computer (dunno how) and offered 
> "computer" formats - so I run it at 1360x768x60Hz. It doesn't offer 
> any "tv" formats/frame rates.
> I don't recall having to make any settings to get the analogue audio 
> input to work with it either.
>
> Since I don't own any other HDMI devises, I can't comment on what 
> happens if you plug one of those in.
>
> The only problem I see with running at 60 Hz is on panning/tracking 
> shots with strong verticals in the frame. I assume it's related to the 
> disparity between source and display frame rates (we use 50 fields/s, 
> 25 frames/s here), but I get a horizontal discontinuity where there is 
> a join between different frames - eg if there is a vertical line, it 
> is broken part way down the screen and the two bits aren't in line. 
> The join moves down the screen over a period of several seconds.
>

What you describe is called tearing, and is not caused by the frame 
rate.  If you're using VDPAU, it's usually caused by not disabling 
compositing.  You can disable it by running:

sudo nvidia-xconfig --no-composite

and then restart X (or reboot).



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