I hope this isn't off-topic. While technically about video production, it's not about a problem I am having.
Have you ever noticed on TV how the color red is always noticeably pixelated? It's the same why while watching video on the computer, as well, be it a Blu-ray, DVD, a video playing directly from disk, or a video being streamed from the internet. No other other that I know of looks pixelated like the color red. I've noticed this since as far back as I can remember starting with DVD. I haven't watched any VHS tapes for many, many years, so I can't say whether or not this pixelation occurs with tapes, but it'd make sense to think that it wouldn't since those are analog.
BTW, I've searched for this online and found a lot of people asking the same questions, but I have yet to see an actual answer.
Here's an example of red pixelation that I just happened to come across on YouTube, although the same thing occurs even on TV broadcasts. Although you can still see it at actual size, zooming in lets you see how pixelated the color red is in comparison to the rest of the colors which really aren't pixelated at all. I strongly doubt that this is merely a visual anomaly. Instead, I believe it has to do with how the color red is processed during encoding.