請教PS4 Pro 畫面輸出2160 YUV420 & 2160 RGB分別

rchan0901

師兄們，近日在試我部LG 65UB9800 (2014款）無HDR 4K TV時，PS4 Pro 經 X5200W 去年電視，ps4 pro畫面輸出設為自動，見到畫面訊號為RGB 4:4:4, 而AV AMP見到Colour space為RGB 4:4:4, 而pixel depth為由8bit

但昨天試將ps4 pro轉為YUV420輸出時，AV AMP見到Colour space為YCbCr 4:2:0, 而pixel depth轉為12bit.

請問從上述資料顯示，PS4 pro出YUV4:2:0 (YCbCr 4:2:0 12bit)定 RGB 4:4:4 8bit 好D呢，D數字又點解呢？

rchan0901

2160p RGB is ALWAYS better than 2160p YUV420, unless your TV/monitor has compatibility issues.

RGB and YUV420 here are compression modes. RGB is uncompressed, while YUV420 compresses video data to 1/2 of their original size.

YUV420 is there because some old 4K TVs support only HDMI 2.0 metadata, but not HDMI 2.0 bandwidth of 18Gbps. However, fully uncompressed 2160p 8-bit (SDR) RGB video requires 17.82Gbps (at 60fps, same below), which exceeds the limit of those old TVs. On the other hand, 2160p 8-bit (SDR) YUV420 video requires only 8.91Gbps, and will work without any problem. In such cases, players are not able to choose 2160p RGB at all, due to bandwidth limits.

For new 4K TVs that support HDMI 2.0 bandwidth of 18Gbps, it is obviously that they are capable for both 2160p 8-bit (SDR) RGB (17.82Gbps) and 2160p 8-bit (SDR) YUV420 (8.91Gbps). To get better video quality, we have no reason to choose YUV420 over RGB.

For HDR videos, it’s a bit tricky. Theoretically, uncompressed 2160p 10-bit (HDR) video requires 22.28Gbps and therefore exceeds the limit of HDMI 2.0, so it won’t work at all. On the other hand, 1/2 compressed 2160p 10-bit (HDR) YUV420 video requires only 11.14Gbps, and will obviously work without any problem.

I guess many people made a mistake here. At first, I too thought that I could get 10-bit (HDR) video only with output mode set to 2160p YUV420 because 2160p HDR RGB exceeds the bandwidth limit. However, when you play HDR contents with output mode set to 2160p RGB, PS4 Pro actually outputs in 2160p 12-bit (HDR) YUV422 (17.82Gbps). So, what is this mode?

As we mentioned before. RGB is uncompressed, while YUV420 is 1/2 compressed. Similarly, YUV422 is 2/3 compressed. It provides better video quality than YUV420 but not so good as RGB. The HDR mode used in PS4 is 10-bit HDR. However, there is no video mode in HDMI 2.0 standard for 10-bit YUV422, so 12-bit YUV422 video mode is used instead, where 2 bits are padded with zero.

In sum, 2160p 12-bit (HDR) YUV422 is the best video quality Sony could provide given this and that limits of HDMI 2.0, and you could only get it when PS4’s video output is set to 2160p RGB. If you choose 2160p YUV420, compared to 2160p RGB, you will get only 1/2 video data for SDR contents, and only 3/4 video data for HDR contents, respectively.

從網上找到的，很有參考性

mark1

要睇返您source 同display 既輸入輸出係咩， 要對返，
可考慮以下文章

http://lysandria1985.blogspot.hk/2014/06/htpc14.html?m=1#more

Anthony :

https://post76.hk/forum.php?mod=viewthread&tid=259500&highlight=4%3A4%3A4&mobile=2


https://youtu.be/7JYZDnenaGc
Skip 到2分中開始睇 一睇就明 444 420 係咩

rchan0901

thx ching