Axiom Home Page Forums General Discussion Home Theater The BS of HDR-TV and any high resolution video

Sadly that is in fact totally wrong. There is more than sufficient colours inside an 8bit colour space. If what you said was true, then every single photograph that you take with a digital camera would come out with blazing banding and there would be riots in the streets because instgram would have failed. Oh the HORROR.

The banding you see it due to terrible artifacts caused by excessive compression. if you look up how H.264 works, it takes this massive amount of data and tries to compress it in a manner that has the least amount of visual impact. Sadly if fails quite badly at it. One of the techniques to compress an image is like a .jpeg where it cubes off a section of the image and then describes the colour of each pixel block by an offset to it's neighbouring pixel block. But even that takes up quite a bit of data space. So rather than doing each and every pixel, it starts to group almost near colours as just being the same colour. When you reach a point that the difference exceeds the delta, then you step up to another colour group. But sadly where you might have had 20 different colours, it has grouped all those as being a single colour. Then the next group can be a good 20+ shades of that colour different, so you get a band.

To see this in action. Take a photograph with a camera. Load it into you computer and then successively save it as a new jpeg with a higher and higher compression ratio. As around 80% compression you will start to see it slightly, but get to around the 40-45% compression then you will see a definite banding effect on just about any shadow surface where the colour gradually change to darker.

You must remember that the H.265 (the newer one for UHD) they are looking compress the video stream to 1/600 to 1/1000 of it's original size according to the spec.

Isn't the false contouring you're describing actually caused by compressing the gray scale? The symptom is in the color reproduction IIRC. Blue skies around a sun become halos etc.

Current TVs have modes and alorithms to handle this. HDR is supposed to eliminate it (supposedly.) I really want to demo one with 4K native content. Maybe in a year or so.

Hansang, how many 4K titles are on Netflix US so far? Is the tv you are using capable of true 4K and 10bit color with HDR? Just curious if the 4K content in FauxK is good/better/worse on a fully equipped TV vs a current model. I think there are only 3 or 4 models that are legit 4K/HDR/10bit ready. I need to start reading up on TVs again, but the Video jargon always puts me to sleep.

The color gamut does not have to do with what colors fill up the 8 bit color space, that's the color depth. Color gamut concerns what that color space is -- what physical wavelengths the R, G, and B primaries have. The current standard for video, rec. 709, has R/G/B primaries and hence the color space defined in a way that the resulting color space is substantially smaller than that of human vision. The new standard, followed for UHD blu-ray, rec. 2020, has a wider gamut, but still smaller than the range of colors we can see in nature.

Here is an excellent online reference on color gamut. It will help you get oriented. The Pointer's Gamut

Not true 4K. It's UHD at 3840 x 2160. Amazon's own series Bosch being one of them are in UHD. Netflix has their own shows in UHD as well. And few others like Breaking Bad. Youtube has plenty of samples of "4K" videos as well.

And of course S6 and GoPro records in UHD 3840x2160 so that works out nicely.

However, I don't think it has 10bit color since it's a "cheaper" 4K model. I never buy the top end anymore due to constant changing technology. However, I do give a "thumbs" up on the remote. The built in pointer function (remote works as a pointer so you click on things) is surprising useful.

Hansang

Yes Greg. You are so much smarter than I am and obviously know everything, so I will just shut up and defer all the answers to you.

Aren't Canadians supposed to be polite?

Oh shut up Peter!


I come back after a few months to this?
who stirred that pot anyway?

Geez Matt, you react as if someone slapped your mother after saying they heard impossible differences between amps because they did a listening test under completely uncontrolled, non-blind and biased methods in their own home but that everyone should just "believe" them.

Of all the posts in the forums, this one was actually good for info on non-audio topic. Greg has supplied a link to more info which is worth reading. Not everyone knows about everything.
Perhaps the link of info is worth considering and then responding to, assuming you have knowledge or expertise to address his response.

Sheesh.

I for one have not been following the latest in video compression. I suspect that once we gear up for a new large format tv in the media room i'll begin researching the topic again. I just don't like LED so this waiting game for something, perhaps OLED, is just painful.

Visit your brother, chesseroo.

LOL
When in doubt, blame a close family member for plausible deniability.
Got it!

Might consider traveling south next year for a short stay.
On the agenda for local attractions to see, Peter and the boys hometown micropub crawl.

Then Matt swung his arm through the Jenga tower. Rough day man? I thought Greg was helping too (especially after the bold you're totally wrong. Lol.)

It's easy to get muddled up in the minutia of video jargon. Gets me too. Dont sweat it Matt.