[mythtv-users] Colour Saturation Problem

Brad Fuller bradallenfuller at yahoo.com
Tue May 31 22:13:19 UTC 2005



Ian Trider wrote:

> Sorry for failing to be totally clear. What I was implying was that
> you should use Video Essentials with your DVD player connected
> straight to the TV to calibrate the TV's colour (again, assuming the
> DVD player isn't stupid and putting out bad colour),

yeah.. that's what I do.

> and then connect
> the DVD player to the capture card, and capture a test image, load it
> into a photo-editing program (like GIMP), and use the eyedropper to
> verify the values are right (I don't know if gimp will show you the
> numbers the right way; the colour bars on the DVD are probably
> described as being 75% saturated red/green/blue, or W/E -- I have
> Avia. Check the description so you know what you should be looking
> for).

good idea.
But, doesn't this just test the capture ability of the card? 
Furthermore, I would expect that a capture via composite and then via RF 
would show differences.

Wouldn't you also need to calibrate the output of the card with images 
that are known to be correct?

If true, how does one calibrate the input and also the output of video 
cards?

>
> Once you know your capture card is good (because they are MISERABLY
> calibrated, especially bt878's), you can output that captured test
> image that you know to be captured in proper calibration to the TV.
> Adjust the video card's colour/brightness settings until the image
> displays (on the TV, which we know to be properly calibrated because
> we did it earlier) the way it aught to.

good idea. thanks

>
> After you've taken all the time to do that, everything should be
> decently calibrated (or at least, as best as possible when going by
> eye).
>
> :) 



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