Slightly OT: 4:2:2 or 4:4:4 Consumer Delivery?

Hulk wrote on 8/17/2009, 11:31 AM
We all know that when viewed from an appropriate distance 4:2:0 encoding, when done properly on good source material, looks very good at 1080p. I know on my Sony 52" XBR4 good BD's look pretty amazing.

But I'm wondering what will happen when affordable high quality screens reach 80 or 100" or larger. Eventually the picture will start to break down.

It seems likely that 1080p will be with us for quite a while as manufacturers will most likely stay with a format that is currently supported by hardware and software.

So I'm wondering if eventually we might see a 4:2:2 or 4:4:4 consumer delivery format to eek that last bit of performance from the 1080p standard. Of course current viewing devices could handle it. Computer playback wouldn't be a problem. I don't know how difficult it would be to adapt BD discs and players to such a format but it seems as though it might be accomplished relatively cost effectively.

I know that the human eye can see some of the detail between 4:2:0 and the other color spaces I mentioned but when you start to magnify pixels there definitely is a visible difference.

And it seems like there is plenty of space available on most BD's since a dual layer disc can hold 50GB and most movies are only about 30GB or so. I personally could do without most of the extra garbage for a version encoded using a better colorspace.

Just a thought.

- Mark

Comments

TheDingo wrote on 8/17/2009, 1:14 PM
I doubt this will ever happen, as most consumers can barely recognise the difference between 480P and 1080P video formats.
Coursedesign wrote on 8/17/2009, 7:17 PM
I'm convinced 4:2:2 will come, and it's getting easier and easier to do it. The numbers refer to "color sampling" which in the case of 4:2:2 means that only every other color sample is thrown away.

4:1:1 (ye olde NTSC) and 4:2:0 (PAL and DVDs) throw away 3 out of every four color samples.

"Color space" is something different. This has already been expanded in some Sony and Panasonic gear. Also referred to as "gamut" (from French), it refers to "how many different colors" can be reproduced.

I suspect Glenn Chan's web site has more on this.
GlennChan wrote on 8/17/2009, 10:10 PM
The chroma subsampling articles on my website have too much detail on somewhat related issues. The first bit of the article describes chroma subsampling artifacts I believe.

2- There is a movement in the consumer space towards wide gamut color, e.g. xvYCC.

(I don't think it's a great idea but that's another story.)

In any case, if they introduce that, I think they should introduce it with formats that support 4:4:4 color sampling. The problem with 4:2:2 and 4:2:0 is that reducing the chroma resolution only works when you are dealing with not-extremely-saturated colors... otherwise you can see artifacts. The whole point of wide gamut is to have extremely saturated colors.

I'm not 100% sure about the details on wide gamut so I don't know if they can just jam it into existing formats.

3- With larger screens, people will still sit some distance away so I don't think any chroma subsampling issues will be a big deal. In most cases, they are too subtle to worry about that much in a consumer system.
Coursedesign wrote on 8/18/2009, 7:59 AM
With larger screens, people will still sit some distance away so I don't think any chroma subsampling issues will be a big deal. In most cases, they are too subtle to worry about that much in a consumer system.

"Consumer" spans a wide range from "drunk pot-smoking frat boy who grew up watching 19" hotel TVs with analog cable," to "discerning viewer who spent years getting every link in the chain just right, down to even optimum viewing distance and the room lighting."

I think subsampled chroma is interpolated to 4:4:4 in high end large screen sets, but that can obviously only do so much. As you point out, tighter chroma sampling is particularly important with more saturated colors.

I'm not 100% sure about the details on wide gamut so I don't know if they can just jam it into existing formats.

They have, so if you pick the wrong setting for display properties, a color of say 232-18-21 will look different from how it was intended. Could look pleasant though, and to many consumers "more" is always better...