Darker output could be because of gamma getting applied twice ?

[stuaxo]

Could the darker output be because gamma is applied by the device outputting to hdmi, then once this is used as input, gamma will be applied again before it is sent to output?

[dekarl]

Looking at the pictures at https://blog.benjojo.co.uk/post/cheap-hdmi-capture-for-linux it appears as if dark parts become to light and light parts become to dark. Could that be that the device returns studio levels but the metadata says its full RGB levels? Random link: http://referencehometheater.com/2014/commentary/rgb-full-vs-limited/

[stuaxo]

Looking at this https://pcmonitors.info/articles/correcting-hdmi-colour-on-nvidia-and-amd-gpus/ it seems like a definite possibility.

Probably need somebody that has this device to play with the output settings for the signal being sent to the HDMI and see how this affects things.

[ValZapod]

gamma is applied by the device outputting to hdmi

Gamma is not applied, HDMI uses nonlinear values already from files. Nobody gets to linear space, unless we are talking about mpv or Photoshop.