HDMI: Image on TV too dark

[Alex Deucher]

On Wed, Oct 12, 2011 at 4:54 AM, Frederik Vogelsang
<frederik.vogelsang at googlemail.com> wrote:
> Hi,
>
> I am experiencing a strange issue: I have connected my TV to my
> computer via HDMI (AV receiver in between them) and whenever I play a
> movie on my PC the picture looses it's details in dark scenes (dark
> areas become just black). First I tried to change the settings on my
> TV (brightness, contrast, ...) but this did not really make a
> significant change.
>
> I finally tracked down the problem to the brightness setting on the
> computer. When I change the brightness with
>
> $> xcalib -b 8.0 -a
>
> the picture on the TV looks fine. Is this normal? I thought since I am
> using all digital connections I would not have to deal with things
> such as brightness any more. Could there be anything wrong on the
> driver side (default brightness value wrong)? Is there any way to
> change the brightness level without xcalib (maybe xorg.conf)?
>

If it's movies, you might need to adjust the Xv attributes
(brightness, contrast, saturation, hue, colorspace, etc.) if you are
using Xv.  Your movie player may have an interface to adjust them, if
not, try something like xvattr.

Alex

>
> GFX: Radeon HD 3870
> TV: Panasonic TX-L37V10E
> SW: Linux 3.1-git, mesa-git, xf86-video-ati-git, libdrm-git, KMS
>
>
> Regards,
>  Frederik
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