Background color problem

I watched a video about DaVinci Resolve on YouTube and in some point I noticed unevenness in the background colors as follows.



Can you please tell me what causes this phenomenon and what this guy is doing wrong with his editing ?

Are you talking about the shadow over his shoulder?

I did a screen grab of the image and boosted the tonal curve way up, which reveals this banding artifact in the background:

DPgfCnC1.png (83.09 KiB) Viewed 265 times

Is this what you're talking about? (It's possible this artifact was introduced by the conversion from your original footage to the PNG image you posted).

If this is what you're talking about, it's caused by insufficient bit depth to render the subtle differences between fine gradations of black and near-black tones. However I did not notice it in the original image, only when I stretched the tonal curve excessively.

If this is what you're talking about, it's caused by insufficient bit depth to render the subtle differences between fine gradations of black and near-black tones. However I did not notice it in the original image, only when I stretched the tonal curve excessively.

Thank you very much for your reply. Yes. This is what I am talking about and I can see it in the original picture and video very well. I was not able to post a link to the original video but I'll try again:

If you can see the picture I posted here (and the original video) without banding artifact then it tells me the problem is in my computer settings...

Thank you very much for your reply. Yes. This is what I am talking about and I can see it in the original picture and video very well. I was not able to post a link to the original video but I'll try again:

If you can see the picture I posted here (and the original video) without banding artifact then it tells me the problem is in my computer settings...

I can see it in the video if I view in a dark room. YouTube compresses video pretty aggressively to save space and is not known for the best quality.

what causes this phenomenon

8 bit video.

The banding in the background is due to YouTube compression. It is not there on the original videos.