Over at Projector Central, Michael J. McNamara, former Executive Technology Editor of Popular Photography magazine and a renowned expert on digital capture, storage, and display technologies writes:
“Does using 4:2:0 subsampling significantly degrade image quality for movie viewing versus using 4:2:2? Not according to most viewers who’ve enjoyed any number of 4K UHD SDR and HDR Blu-ray movies. That’s because 4:2:0 is actually the chroma subsampling level required by the 4K UHD Blu-ray standard (along with the incredibly efficient HEVC global compression algorithm) and is actually used to store just about every movie you’ll watch from your cable TV or streaming provider.”
We’ll let you be the judge. Download a side-by-side comparison between ProRes 4444 XQ, HEVC 4:2:2 and 4:2:0 here. We recommend dropping the file on the timeline of your preferred NLE, setting the project to HDR PQ and viewing on an external calibrated display. Crucially, what the author fails to disclose is that the streaming giants use ICtCp encoding, not obsolescent Y’CbCr, which works well enough for SDR movies, not so much for HDR WCG. There is also little doubt that, if UHD Blu-ray collectors were able to see a comparison between faded 4:2:0 and 4:2:2, they would invariably choose the latter.