36 bit or actually not 36 bit - this is something worth discussing

ellisdj

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Dec 11, 2008
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I have done a search and its come up before but not discussed at any length I wonder how many people are doing the same as me.

To my knowledge all the blu ray players I have owned have outputed 36bit - that is what comes up on my Kuro, however with the LX55 you have the options of off, 30bit and 36bit.

I automatically put it on 36bit - however another set of eyes (my cousin the same set that always debates with me) told me that he had read that all blu rays are shot in 24 bit - therefore if 36 bit is selected the BD player is upscaling the colour palette.

Now some players will do this flawlessly with the majority including the reference level LX91 will actually add errors to the colour.

What is the theory and thougths of the masses on here. I am not sure what I thought was best and will test more

Second Point to Note - this one was a lot clearer

Blu Rays are apparently shot in Ycbr 4.2.0 and the edited to 4.2.2 - therefore there is upscaling of the colour pallette again if you select Ycbr 4.4.4

I have always had my Kuro and Blu rays set on Ycbr 4.4.4 - however again recent tests (yesterday) have proved that 4.4.4 blooms the colours and 4.2.2 appears far more natural.

I have the luxury with the Kuro to set the colour specifically at 4.4.4, 4.2.2 RGB or RGB Full, I know other TV's do not give you these options.

By Contrast I have always found selecting RGB especialy Full RGb to produce a lower quality image with crushed blacks

Again what are the thoughts of the masses
 

Dan Turner

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Jul 9, 2007
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Great info Das. So if your Blu-ray player were the most recent/strongest component in your replay chain what would settings would you use for the colour scheme and deep colour bit depth (assuming that the blu ray player will do the best job of whatever up sampling etc needs to take place)
 
A

Anonymous

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Unfortunately there isn't a universal answer because it really does depend on the specific combination of products in the display chain.

Using the assessment material mentioned above is the best advice.
 
A

Anonymous

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There's a difference between how something is “shot” i.e. captured on film and how it's processed for presentation on a particular medium such as DVD or Blu-ray. Blu-ray and DVD use a form of chroma subsampling (compression) called YCbCr 4:2:0 that’s encoded at 8 bits per channel.

For example if the overall image is 1920x1080 using YCbCr 4:2:0 means the Cb and Cr portions of the image is 960x540 resolution. Standards dictate that all players must upsample chroma i.e. interpolate values for the missing pixels to at least YCbCR 4:2:2. This increases the Cb and Cr portions to 960x1080 but ultimately the chroma must be fully interpolated to match the 1920x1080 overall image resolution somewhere i.e. player, processor or display etc. In reality this is about video processing and what's best performed where in the chain for a given set of products. Similarly with 8 bit source HDMI bit depth is also related to processing or rather avoiding rounding errors/truncation that occurs when calculations are performed at higher bit depth and subsequently reduced at transmission. YCbCr 4:2:2 can support up to 12 bits per channel over HDMI whereas YCbCr 4:4:4/RGB is limited to 8 bit per channel without HDMI Deep Colour support. HDMI Deep Colour provides a means to transmit fully upsampled chroma formats at "deeper" than 8 bit per channel.

The question of what to output from the player really boils down to the combination of products and if there is an optimum choice. Some devices (or even different video chips within the same device) will automatically convert all input to a native scheme and/or truncate bit depth beyond HDMI for internal processing. In these circumstances feeding the device its native format may avoid possible degradation due to multiple conversion steps.

Assessment material such as Spears & Munsil Blu-ray can help determine if there is an optimum chroma scheme choice for a combination of products using the chroma multiburst and chroma zone plate patterns. Using these chroma resolution patterns together with the other key assessment patterns should help establish the best option and/or any side affects in other areas from using different colour space choices. If the display has a CMS display chain calibrating the displays gamut should provide a means to accurately set colour saturatuon and luminance to the appropriate standard.

Usually using "video" rather than "PC" level formats will produce optium results with DVD and Blu-ray dependiong on your calibration goal and the combination of products. Changing between video(16-235) and PC (0-255) formats may require black/white levels to be recalibrated as appropriate.
 

ellisdj

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Dec 11, 2008
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Thanks to the advice above, other info from other forums and some more testing I have actually found that using the LX55 in RGB mode gives the best overall picture - but its bloody tough.

This decision was based on information found on another forum

someone posted that Pioneer Kuros process the data in RGB - therefore the decision was either have the TV process the data and feed it 4.2.2 or have the Blu Ray process it and feed it RGB.

It amazed me to see it looks better processed in the Blu Ray.

Does anyone else with a Kuro use these settings - or know any different?
 

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