What is Chroma Subsampling?When you compare the 100% crops of 1080p video straight out of the Galaxy Note 3 or any smartphone or even a dedicated video camera compared to 4K video resampled at 50% of it’s original sized (interpolated 1080p video), you should be able to see a big difference in quality. It is due to a limitation brought on by chroma subsampling in the 1080p video on the left.
To understand what chroma subsampling is, let’s imagine a grid of pixels representing 1080p video. It is approximately 2 million individual dots of color. Let’s zoom into a single pixel, which is made up of 3 different pieces of data. The luma value Y that tells us how bright that pixel should be. And the two chroma values Cb andn Cr that tells us what color the pixel is.