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Difference between HDMI RGB and HDMI Y Cb Cr?

1159 Views 12 Replies 11 Participants Last post by bruce73, Oct 18, 2004

V. Rossi

Discussion Starter · Oct 13, 2004

The Denon 2910 has these two HDMI modes. HDMI Y Cr Cb says it outputs the component signals from the HDMI connector, and HDMI RGB outputs the RGB signals. What's the difference?

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As I understand it, the HDMI standard allows for output to be a digitized version of either RGB or YCbCr. I also believe that DVDs are encoded as YCbCr. Thus, there is no color space conversion if you output YCbCr over HDMI.

On the other hand, DVI is only an RGB interface. Thus, if you want to send an HDMI signal through a conversion plug to a DVI device, you have to convert from YCbCr to RGB first.

Ira

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V. Rossi

Discussion Starter · #3 · Oct 13, 2004

I have an HDMI to HDMI cable connected to my HS-20 and cannot see a difference between the two HDMI modes when I switch back and forth. If DVD is encoded in YCbCr, I guess I should set it to this then?

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Charles R

· #4 · Oct 13, 2004

I see a color shift when I A/B the two settings. On gray test patterns they are identical... I'm using HDMI to DVI and I haven't spent a lot of time comparing but for some reason I prefer RGB. Don't ask why cause I couldn't tell you.

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rgfcpq

· #5 · Oct 15, 2004

I am curious what other settings 2910 users are applying and where they are making adjustments (dvd player, tv, receiver). I have a sammy hlp 5063, a denon receiver, and a the 2910 dvd player.

A couple questions/comments:

1) Why would I want to adjust the video or audio settings on the dvd player when I can adjust them (uniquely) on the HLP and the Receiver, respectively?

2) Using the HDMI connection from the DVD player to the TV, it's still not clear to me which HDMI setting to use ( Y Cb Cr vs. RGB). Which should give me the best picture?

3) I am seeing a greenish cast to dvd's using the 2910 -- what are people doing to adjust this down, if they are esperiencing it?

4) Which output format should I use to get the highest quality picture -- 720p or 1080i? I don't notice much of a difference in my setup.

Thanks for the replies.

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nash0r

· #6 · Oct 15, 2004

One I can answer is to use 720p. There is no reason to send a 1080i signal to your TV, which will then scale back to 720p as it is the display's native resolution. If you ship 720p straight to the TV, then there's one step of scaling that you eliminate.

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iblumberg

· #7 · Oct 15, 2004

Quote:

Originally posted by rgfcpq
I am curious what other settings 2910 users are applying and where they are making adjustments (dvd player, tv, receiver). I have a sammy hlp 5063, a denon receiver, and a the 2910 dvd player.

A couple questions/comments:

1) Why would I want to adjust the video or audio settings on the dvd player when I can adjust them (uniquely) on the HLP and the Receiver, respectively?

2) Using the HDMI connection from the DVD player to the TV, it's still not clear to me which HDMI setting to use ( Y Cb Cr vs. RGB). Which should give me the best picture?

3) I am seeing a greenish cast to dvd's using the 2910 -- what are people doing to adjust this down, if they are esperiencing it?

4) Which output format should I use to get the highest quality picture -- 720p or 1080i? I don't notice much of a difference in my setup.

Thanks for the replies.

For 1, if you have only 1 HDMI port on your TV and are switching multiple HDMI sources with a switch box or receiver, you may want to adjust the sources to look as similar as possible in terms of color, saturation, contrast, brightness, etc. That way you can optimize your TV using the DVD player and other signals like STB will look just as good without further adjustment.

For 2, I suggest using YCbCr. As I said above, I believe this is the format in which DVDs are recorded. Thus, by sending the data in this format, you are avoiding at least one color space conversion, i.e., the conversion from native YCbCr to RGB.

I find 3 rather disappointing. I have a 1910 and it sometimes shows a greenish cast. I was planning to try the 2910 to see if that eliminates it.

I agree with nash0r on point 4. Use the DVD player to scale to the native resolution of your TV. When scaling is done in the DVD player, in theory, it is cleaner as it happens before any other conversions or interfaces. Also, many TVs now take their scalers out of the loop entirely when fed native resolution over DVI/HDMI, thus you may well bypass that circuitry completely.

Ira

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jfinneru

· #8 · Oct 15, 2004

Read the manual for the denon 3910 yesterday and if you want to use whiter than white and blacker than black you need to output hdmi rgb. if you use the other one the black setting in the meny will have no effect. tried this yesterday and the black level became much better when outputting hdmi rgb and black set to enhanced.

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svh9633

· #9 · Oct 15, 2004

I can't get it right. If YCbCr is sent to a LCD or DLP it has to be konverted to RGB somewhere?! The only use for YCbCr is in CRT-based displays?

jfinneru: Noone except you uses black enhancement, that will make your HDMI output to cruch black and white i.e. PC signals.

Correct me if I am wrong.

/Sam

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joerod

· #10 · Oct 15, 2004

Actually the 3910 manual also says that if you use a HDMI to DVI then the signal is automatically switched to RGB. DVI is only compatible using RGB.

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alpinefool

· #11 · Oct 18, 2004

Someone must have an answer. Why are both setting there if they do not have specific advantages. I'd buy that YCbCr is better and RGB is only for HDMI to DVI, but why not go DVI to DVI?? Is it true that DVDs are coded in YCbCr? I've been searching fore info and can't verify that. I've actually found sources that claimed dvd's were coded in RGB. Has anyone asked Denon for more info?

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Waterbug

· #12 · Oct 18, 2004

dvd movies uses MPEG-2 that uses YUV/Y Cb Cr, not RGB...

the YUV is at 4:2:0 sampling.

they do that to save bandwidth and backward compatible with composite and s-video. Whereas, a 24 bits RGB (8 bits each) probably don't have enough sufficient memory to stored video. 4:4:4 YUV sampling can be comparable to 24 bits PC RGB( or as someone told me 8 bits studio RGB).

Also, DVD don't have that storage to store 24 bits PC RGB or even 16 bits PC RGB without higher compression.

DVD MPEG-2 can compress as low as 13:1 to as high as 40:1 compression and that's just using 4:2:0 Y Cb Cr sampling with resolution of 720 x 480 and maximum of 30 frames per second.

Blu Ray/ HD-DVD have a much higher storage. But it can only store lossless video compression at DVD picture quality, its possible that next generation format after Blu Ray/ HD-DVD will we be able to watch movies in lossless high definition video at color bandwidth higher than 4:2:0 say 4:2:2 YUV... or uncompressed standard def video with 24 bts PC RGB color...

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bruce73

· #13 · Oct 18, 2004

So, with a straight HDMI>HDMI connection to a DLP, is YCbCr the optimal choice?

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