[mythtv-users] VDPAU picture degradation, possibly since 0.24 to 0.25 switch

[Michael T. Dean]

On 08/19/2012 03:40 PM, Paul Gardiner wrote:
> For some time now I've felt I was getting worse picture
> quality than I used to. It's very subtle so I wasn't sure
> if I was imagining it or not, but now I have definite
> evidence that my myth frontend is the cause. It seems
> to be producing too high a contrast even though all
> picture settings are at 50%. It isn't because of confusion
> over studio and PC settings. My TV can be set to expect
> either, and I see the same problem with TV and Myth set
> to studio or with TV and Myth set to PC.
>
> Tonight while watching the news I noticed a strongly
> lit skin area that looked wrong in colour. The pink
> went to yellow and then to white as the intensity
> increased. If you think about it, that's exactly
> what you'd expect if the RGB values were being
> clipped: for pink, R is strongest then G then B.
> First R would become clipped, making the colour
> yellow, and then both R and G, making the colour
> white.
>
> When I'd noticed that sort of discolouration before,
> I'd put it down to the source, but I realised tonight,
> that if it was the source, it should be impossible to
> adjust it out. That's where I got the evidence that
> the problem with the frontend: I found that I could
> adjust it out, but only by adjusting Myth's settings,
> not by adjusting my TV; it seems the RGB values are
> being clipped before getting to my TV, hence it must
> be Myth that's doing the clipping.
>
> Has anything changed in the YUV => RGB conversion
> for vdpau recently? Or has anybody noticed a problem
> with recent nvidia drivers?

/me guesses studio colors aren't properly configured on your system

Mike