YCbCr 444 Vs 420? HDMI Mode 1 Or 2, Which Is Optimal? - AVS Forum

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porschedrifter

Hey guys, a bit confused on this one setting on my new 4k tv. There's an option for HDMI mode 1 or 2. After reading the manual, I'm not sure what option will give me the optimal quality. I found this link talking about the new HDMI 2.0 spec here Is that what this option does? And if I want the best picture quality possible, which option should I choose, 1 or 2? Thanks! The manual says: Selecting the HDMI Input mode The HDMI jacks on your TV are Ultra HD (UHD) jacks. Depending on the UHD device you connect to the HDMI jack or the streaming content you watch, youmay need to adjust the timing. Mode 1 YCbCr 422/444 (supports timing limit on 3840x2160@30Hz) Mode 2 YcbCr 420 (supports timing up to 3840x2160@60Hz) #1 · Dec 2, 2016 Hey guys, a bit confused on this one setting on my new 4k tv. There's an option for HDMI mode 1 or 2. After reading the manual, I'm not sure what option will give me the optimal quality. I found this link talking about the new HDMI 2.0 spec here Is that what this option does? And if I want the best picture quality possible, which option should I choose, 1 or 2? Thanks! The manual says: Selecting the HDMI Input mode The HDMI jacks on your TV are Ultra HD (UHD) jacks. Depending on the UHD device you connect to the HDMI jack or the streaming content you watch, youmay need to adjust the timing. Mode 1 YCbCr 422/444 (supports timing limit on 3840x2160@30Hz) Mode 2 YcbCr 420 (supports timing up to 3840x2160@60Hz) See less See more Sort by Oldest first Oldest first Newest first Most reactions #2 · Dec 2, 2016 Set to 420 because movies are mastered in the "Limited" color range. YUV420 is correct. I would have said 4:4:4 if you use a HTPC and play games, but seeing as your TV only supports 30hz at that range anyway, then it is silly to have a 30hz functioning desktop. If you do have a HTPC/console, set them to the "Limited"/YUV420 color range and you'll be fine. #3 · Dec 2, 2016 Ok thanks, I do have 3 different hdmi inputs right now going into it, one is a dedicated PC for htpc use as well as video editing playback, 2 is xbox one and 3 is ps4. 0 Reply #4 · Dec 2, 2016 Enable it, it just enables the 600MHz clock rate of HDMI 2.0. There is no reason to have it disabled. Even with it on the source device will negotiate whatever it thinks is best or what you set it to. Keep in mind that most TV's process internally as 4:2:2 unless you switch them to some sort of PC/4:4:4 mode. Example 4K Source device direct into the TV: (I believe 1080P devices convert the 4:2:0 to 4:2:2 before sending it to the TV) YCbCr 4:2:0 > RGB Half Chroma (4:2:2) > Video Processing > RGB Full Chroma > TCON > Panel You'll end up with higher quality output (especially in colors) if your display has a option to do the video processing in full chroma resolution. Note: If you have HTPC receiver in the path there might be even more color space conversions going on. #5 · Dec 2, 2016

porschedrifter said: And if I want the best picture quality possible, which option should I choose, 1 or 2? Thanks! The manual says: Selecting the HDMI Input mode The HDMI jacks on your TV are Ultra HD (UHD) jacks. Depending on the UHD device you connect to the HDMI jack or the streaming content you watch, youmay need to adjust the timing. Mode 1 YCbCr 422/444 (supports timing limit on 3840x2160@30Hz) Mode 2 YcbCr 420 (supports timing up to 3840x2160@60Hz) Click to expand...

The difference as correctly written by Quad5Ny is that with Mode 2 it's enabling the HDMI 2.0 to that specific port for more bandwidth, so this is highly recommended if you have connected a UHD BD Player; to be able to pass the infoframe metadata to your display also. Mode 2 it's already supporting the resolution/chroma subsampling Mode 1 features, but 2160p60 YCbCr 4:2:0 additionally.

Quad5Ny said: Example 4K Source device direct into the TV: (I believe 1080P devices convert the 4:2:0 to 4:2:2 before sending it to the TV) YCbCr 4:2:0 > RGB Half Chroma (4:2:2) > Video Processing > RGB Full Chroma > TCON > Panel Click to expand...

About 1080p BD, the players are doing that conversion internally (YCbCr 4:2:0 -> 4:2:2). About ''RGB Half Chroma (4:2:2)'', RGB has always full chroma. #6 · Dec 2, 2016

ConnecTEDDD said: The difference as correctly written by Quad5Ny is that with Mode 2 it's enabling the HDMI 2.0 to that specific port for more bandwidth, so this is highly recommended if you have connected a UHD BD Player; to be able to pass the infoframe metadata to your display also. Mode 2 it's already supporting the resolution/chroma subsampling Mode 1 features, but 2160p60 YCbCr 4:2:0 additionally. About 1080p BD, the players are doing that conversion internally (YCbCr 4:2:0 -> 4:2:2). About ''RGB Half Chroma (4:2:2)'', RGB has always full chroma. Click to expand...

You're right, but I was using 4:2:2 to show that the video processor would convert the YCbCr signal to the Red, Green and Blue channels while keeping Red and Blue at half resolution (to save on processing power). I mean why have two pipelines (RGB/Component) when you can just convert YCbCr to RGB as soon as it is received and then code your image correction for that. *Shrugs* ...Then again maybe the TV keeps the signal as component during the processing/enhancement steps. I actually have no idea, it's not something that I ever looked up (or tested).

Show more replies 0 Reply #10 · Jan 9, 2017 Toshiba TV? You don't mention your brand of TV, but I recently picked up a Toshiba 65L621U from BestBuy for $600. The manual uses that same verbiage concerning the descriptions of "Mode1" & "Mode2". My new video board I'm using with this television is a GTX 1060 6GB. Anyway, in "Mode1" I notice that at 60hz @ 3840x2160 the only option available is YcbCr 420. Once I lower the refresh to 30hz RGB and other modes (RGB, 422, 444) become available. Here is the interesting part. In "Mode 2" in 60hz @ 3840x2160 RGB & YCbCr 422/444 (and obviously still 420) are available as well as "full" and "limited" dynamic range setting. Full range looks better... These settings do seem to be working as I can tell the difference in both the mouse movement 30 vs 60) and quality of small text (YCbCr 420 vs RGB) In the case of my TV, the modes do seem to correspond with USB modes(like you mentioned) and the manual is misleading or just plain wrong. Hope that helps... #11 · Jan 9, 2017 (Edited)

bbond007 said: You don't mention your brand of TV, but I recently picked up a Toshiba 65L621U from BestBuy for $600. The manual uses that same verbiage concerning the descriptions of "Mode1" & "Mode2". My new video board I'm using with this television is a GTX 1060 6GB. Anyway, in "Mode1" I notice that at 60hz @ 3840x2160 the only option available is YcbCr 420. Once I lower the refresh to 30hz RGB and other modes (RGB, 422, 444) become available. Here is the interesting part. In "Mode 2" in 60hz @ 3840x2160 RGB & YCbCr 422/444 (and obviously still 420) are available as well as "full" and "limited" dynamic range setting. Full range looks better... These settings do seem to be working as I can tell the difference in both the mouse movement 30 vs 60) and quality of small text (YCbCr 420 vs RGB) In the case of my TV, the modes do seem to correspond with USB modes(like you mentioned) and the manual is misleading or just plain wrong. Hope that helps... Click to expand...

Hi, with HDMI 2.0, you can have up to 2160p60 with RGB/4:4:4 but up to 8-bit. For 10/12-bit 2160p60, RGB/4:4:4 is not possible, because with 10-bit you need about 22.28 Gbps and with 12-bit you need about 26.73 Gbps; because HDMI 2.0 has transmission data rate up to 18 Gbps. 1 Reply Insert Quotes Post Reply

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