Control Brightness via HDMI

[levy]

Hi Forum

I am new to the forum and this may be a stupid question but I've read the HDMI standard and been googling for ages. Perhaps just the wrong search words.


I have an application where the camera outputs to an LVDS display using FPD link III and controls display brightness via I2C. So far so good and my camera can detect ambient light and match the display backlight.

Now I want to use the same system with LVDS to HDMI converter, which is also working but I can't control the display backlight.

Does the HDMI standard allow for control of brightness/contrast/backlight from the source device (camera / video playback device)?

Regards


Richard

[usually_quiet]

Hi Forum

I am new to the forum and this may be a stupid question but I've read the HDMI standard and been googling for ages. Perhaps just the wrong search words.


I have an application where the camera outputs to an LVDS display using FPD link III and controls display brightness via I2C. So far so good and my camera can detect ambient light and match the display backlight.

Now I want to use the same system with LVDS to HDMI converter, which is also working but I can't control the display backlight.

Does the HDMI standard allow for control of brightness/contrast/backlight from the source device (camera / video playback device)?

Regards


Richard

I doubt it. HDMI includes a feature known as Consumer Electronics Control (CEC), but it's primarily intended to allow devices like Blu-ray players and DVD players to be controlled using the TV's remote control when connected to the TV via HDMI. There are commands that allow other devices to control the TV too, but they seem to be limited. For example, there products for computers that allow a computer to use CEC to turn a TV on/off, and access the TV's volume control,

[levy]

Many thanks for the answer.

It seems that the CEC is not standardised for all displays so I can't use it becuase I don't have ability to modify the displays within the project.

But good to know that brightness / contrast is not simply supported. I thought I'd maybe just missed something in the specification.

[pandy]

CEC is standard and it is supported by large number devices especially modern one (i would do educated guess and estimate over 50 - 75% HDMI 1.4 compliant devices are CEC enabled).
But seem CEC doesn't support brightness and contrast commands http://www.cec-o-matic.com/ (maybe only as Vendor Command) .
Seem to modify brightness and contrast you need to modify video data (which i assume is not good for you).

Alternatively you try to use EEDID information (Sink type) then use IR command to modify settings (but usually brightness/contrast are hidden in menu and they don't have own command).