Pixelated red objects in video

In this video watch the guy on the far left. His red shirt appears very pixelated, much more so than anything else on the screen at all resolution levels, even at “720pHD.” Why?

The resolution/quality at which you watch the video online doesn’t really matter if the limitation is in the quality of the originally-captured footage - and this appears to be a factor here.

The whole thing is quite pixellated and blocky, due to resolution limitations and probably compression artifacts in the video as recorded in the camera. It’s slightly more noticeable in the red shirt, probably because of the lighting, and maybe because of different performance of the camera’s sensor for that part of the colour spectrum - this means the camera might have seen the red shirt as more contrasty, and constrasty things compress differently from smoothly-graduated ones.

He doesn’t look any more pixelated to me than the others.

While this does seem to be the case in this video, I want to point out that pixelization of selected portions of an image is often used for censorship.

I think you mean ‘rastering’, meaning artifacts from raster scanned video. Pixelating is a deliberate process to blur images as** BigT **pointed out. The factor I see is the border between red and black where his sleeves meet the background. A common video camera or scanner is likely to have a pixel be either red or black, instead of dark red. Even higher quality equipment would have difficulty with that coloring in those lighting conditions. The rapid movement of his arms at some points will make the problem worse. Digital processing could smooth out the transition with aliasing and frame averaging.

You’re talking about intentional pixellation. The term ‘pixellation’ is also to describe the appearance of rectilinear features caused by displaying raster images/video above their optimal or intended size.

It’s often also used to describe macroblocking - the introduction of blocky artifacts by digital compression processes. This would be an inappropriate use of the term ‘pixellation’, but quite a forgivable one, I think.

Red is given lower priority in video compression, so it can appear blockier in certain situations. Not that I can really see much pixelation in the video you linked.

Red compresses poorly. It can be tricky avoiding compression artifacts in large red areas if you are trying to achieve a small file size.

All is forgiven.:slight_smile: