[mythtv-users] How to properly adjust brightness and contrast

Richard Woelk richardwoelk at yahoo.ca
Mon Aug 11 16:28:00 UTC 2008


Nick Bright wrote:
> Is there a howto or a document on a wiki somewhere regarding the best 
> way to properly adjust the brightness, contrast, color, and hue settings 
> on a tuner to get things looking their best?
>
> I'm using Happague PVR-150 tuners, and at the default settings the 
> picture is very dark. I've figured how how to adjust the settings, I 
> just really don't know how to properly adjust them all in concert to get 
> the best picture possible.
>
> Any advice is appreciated. Thanks!
>
>  - Nick
>   

I used the Avia DVD repeating a color bars pattern in a set top player 
connected to the s-video input of my pvr-150.
Mythtv keeps the global settings per capture card, not input. It also 
keeps individual channel settings.

While watching live TV, Press CTRL-G to get recorder settings. press G 
to get channel settings.
The channel settings won't start at 50, they will show what the current 
card settings are.

When you increase the contrast too high, it will crush the whites, if 
its too low, the black looks washed out.
The difficulty is that the capture card doesn't clamp the black level. 
so when you adjust the contrast, you'll have to go back and adjust the 
brightness again.
for color and hue, you need the blue filter to look through.

for starters, I found these settings on my PVR-150 OEM from s-video input.
The tuner input is quite a bit worse. (or that could be what my off air 
is like)

Brightness - 48
Contrast - 42
Color - 44
Hue - 50

I also found a filter for virtualdub on windows called color tools that 
let me view vectorscope and waveform patterns. I could import the mpeg 
and see the effects a few seconds later.

I always wished I could use this as a playback filter in mythtv, that 
way it would be a lot easier to set capture properly.

- Richard


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