A common misconception is that digital video is processed and stored as RGB data. At first glance, this might sound reasonable - after all, the input on the camera sensor is RGBG, and your display is RGB. However, this is not the case! Videos are typically stored as YUV (or technically YCbCr in the digital realm). Why? Well, in this video, we explore digital colour and how we encode and represent images and videos on computers. To answer the why question briefly then: efficiency and legacy. YUV and YCbCr are a form of separating the luma and chroma (the brightness and colour) signal to be able to gain efficiency by lowering the quality on the colour component. It also goes back to colour TV working by adding a colour to an existing black-and-white grayscale image. === Timestamps === 00:00 - Introduction 00:21 - RGB vs YUV 01:45 - How YUV Works 04:03 - The UV Plane 06:05 - Similarity to Analog Component Video 07:23 - Why Is This More Efficient? (Chroma Subsampling) 13:04 - Does Subsampling Matter? 15:20 - Why Would We Do This? 17:18 - Conclusion === Helpful resources/more information === https://en.wikipedia.org/wiki/YUV https://www.pcmag.com/encyclopedia/term/yuv https://www.reddit.com/r/computervision/comments/etd8sq/eli5_rgb_vs_yuv/ https://en.wikipedia.org/wiki/YCbCr https://en.wikipedia.org/wiki/YPbPr Fun fact: Red/Blue used by YCbCr/YUV are not the only colour planes. DSC (display stream compression) used for high refresh rate monitors over DisplayPort uses YCoCg uses green(/pink) and orange(/blue) for its two planes! You can also totally notice chroma subsampling in the credits at the outro of @LinusTechTips videos, as they typically use coloured text on a coloured background! === Thanks for Watching! === I hope you enjoyed this video and learned something new! If you found this useful and want to see more videos like it in the future, leave a comment and consider subscribing! You can use this video under a CC-BY-SA license. I used a lot of helpful images from WikiMedia throughout this video. They should all be credited at the corresponding points - unfortunately, descriptions are limited to 5000 characters and so I can't list them out individually here. === Shoutouts === Shoutout to Andy Roberts, Felipe Clark, Paul Janes and Mohammad Ansari from AMD Markham who answered my questions about display technologies and how stuff works. This video was filmed before my term there, but I learned a lot from them. Also a small shoutout to Dixon Huang, Lucas Choi, and Mrugank Upadhyay who had to endure me lecture/rant about topics like this (and have me point out every time they left a display running in YUV 4:2:0 mode when testing FreeSync...) === Clarifications and Corrections === - I use YUV and YCbCr almost interchangeably in this video. I am aware they are technically different/distinct things, but my point is comparing these luminance/chrominance schemes to RGB, and they are all similar enough for that purpose. - Why are all the text fields in the video a different typeface/colour? I edit in multiple passes, and work on multiple videos concurrently. Kdenlive defaults to using the last used settings which differ for each video and I don't change it since it's good enough. Hey, still faster than using Cinelerra... - Color? Colour? Argue it in the comments. It doesn't matter but I'm sure I'll hear how I'm wrong from both sides. Thanks for watching! I hope this video helped you out! Produced by Tony Tascioglu https://tonytascioglu.com

• published: 25 Apr 2023
• views: 6221