Gamma differences between RGB and H.264 streams
I'm using NvFBC to capture a remote screen and compress it with H.264, and decoding the stream with the Capture SDK and displaying with OpenGL on the receiving end. If I switch between capturing raw RGB pixels and H.264, I find that the RGB image is what I expect and the H.264 requires gamma correction. Is there a implicit gamma adjustment happening in the H.264 encoder or decoder that would account for the difference? If so, can we control this or disable it?
I'm using NvFBC to capture a remote screen and compress it with H.264, and decoding the stream with the Capture SDK and displaying with OpenGL on the receiving end. If I switch between capturing raw RGB pixels and H.264, I find that the RGB image is what I expect and the H.264 requires gamma correction. Is there a implicit gamma adjustment happening in the H.264 encoder or decoder that would account for the difference? If so, can we control this or disable it?

#1
Posted 01/08/2018 09:07 PM   
Maybe you hit "limited color space" problem [url]http://kodi.wiki/view/Video_levels_and_color_space[/url]. The problem is usually at receiver end - try another h264 pipeline/player.
Maybe you hit "limited color space" problem http://kodi.wiki/view/Video_levels_and_color_space.
The problem is usually at receiver end - try another h264 pipeline/player.

#2
Posted 01/09/2018 09:55 AM   
That's interesting. I'm pretty sure what I'm seeing is a gamma difference, though. If I apply a gamma correction to the decoded H.264 stream, I can get back a pretty good representation of what I was capturing.
That's interesting. I'm pretty sure what I'm seeing is a gamma difference, though. If I apply a gamma correction to the decoded H.264 stream, I can get back a pretty good representation of what I was capturing.

#3
Posted 01/09/2018 03:08 PM   
Maybe compression generic quatization and/or color conversion lost. Try to encode in 4:4:4. Check [url]https://forums.adobe.com/thread/1063696[/url] or [url]https://forums.adobe.com/thread/1103186[/url] or other Google hits. Check/set parameters in "NV_ENC_CONFIG_H264_VUI_PARAMETERS" . Thats all from me.
Maybe compression generic quatization and/or color conversion lost. Try to encode in 4:4:4.
Check https://forums.adobe.com/thread/1063696 or https://forums.adobe.com/thread/1103186 or other Google hits.
Check/set parameters in "NV_ENC_CONFIG_H264_VUI_PARAMETERS" .

Thats all from me.

#4
Posted 01/09/2018 06:40 PM   
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