Shooting in xvYCC

[Arkady Bolotin]

Perhaps, one of the most neglectable (or the least familiar) features of the AVCHD video standard is support for extended-gamut color space YCC (or xvYCC for short).

Since its inclusion in AVCHD in 2006, Sony and Panasonic actively promote xvYCC (under different names though; for example, Sony uses name “xvColor”) by offering to record in xvYCC with their AVCHD-based camcorders.

However, only few people have chosen to record in xvYCC so far, while many others did not bother to give it a go (even for the sake of curiosity) considering xvYCC as a marketing gimmick. But really, is it only a gimmick?

According to PC Magazine Encyclopedia, xvYCC is a color space with 1.8 times as many colors as standard RGB (sRGB). Whereas sRGB provides a portion of the color spectrum, xvYCC can display every color the human eye can absorb.

This sounds like a very great idea. Still, what does that do in real life? Is it the case of the next technology's first attempt, which is just not ready yet for the time being? Can we already see a clear difference?

In this thread, I am going to show you that, yes – we can already see superior xvYCC colors even without xvYCC-enable TV (but you should have a reasonably modern television or a PC display driven by NVidia, AMD or Intel graphics hardware), and, yes – the difference between xvYCC and sRGB is evident and important enough to justify the effort.

Please observe the results I have got experimenting with xvYCC. I recorded a Munsell ColorChecker Card (see the first attachment) in sRGB and xvYCC color spaces; then I cut colored squares from the frames of the recorded footage and put them together (for the purpose of comparison) so that each xvYCC square would partially overlap the corresponding sRGB square (see the second attachment).

Look closely: you may see that the difference between extended- and standard-gamut color spaces is real, and it is manifested chiefly in the pairs of yellow, green, cyan, and violet squares.

Of course, somebody always could say, well, all right, I see some subtle difference, but the question is “So what? What it can do for me in recording real-life colors?”

Please look at the attachments three (Blue Car.jpg) and four (Flowers.png). They are frames grabbed from xvYCC-recoded clips filming real-life colors. As you can see, even though the difference between xvYCC and sRGB might be subtle, it can help your brain switch into a “real” mode, with the images popping off the screen.

[Robert Young]

Very nice summary.
I had noticed that capability on a couple of my Sony handicams, but never looked into it since it seemed to require a compatable T.V.
Also, since it was not a feature on my pro cams, I just figured it was some sort of consumer sales pitch.
Anyway, always nice to learn something & maybe I'll actually check it out now :)

[Arkady Bolotin]

That is right, Robert, up until the recent time, xvYCC has been exclusively a consumer feature. But now it is getting more serious: recording in xvYCC is one of the functions of the Sony HXR-NX5 – the first professional AVCHD camcorder.

As to an xvYCC-compatible TV, here is the most intrigued part of the whole issue regarding xvYCC recording.

Most people probably think in the similar way: Why to bother setting on xvYCC recording in the camera if you will be able to see the difference only if you get an xvYCC-color TV? Likely, they are guided by the simple analogy with color TV: you cannot see a color program if your TV is old black-and-white one.

However, such an analogy of color and black-and-white TV is not applicable to xvYCC colors. To be able to display colors, a TV set has to have color sub-pixels (and lots of additional devices in it). Contrary to that, no new mechanism, device or piece of equipment is required to transmit or receive the xvYCC video (as it is fully compatible with HDMI's existing YCbCr formats).

So, how does it work? The display needs to signal its readiness to accept the extra-gamut xvYCC values, and the source needs to signal the actual gamut in use to help the display to intelligently adapt extreme colors to its own gamut limitations. In other words, xvYCC colors on the screen of your TV or PC monitor is the function of its software.

This means, that (if your TV or PC graphic board is relatively advanced) there is a great chance you will see some extra colors even if the TV or PC display weren’t officially certified as xvYCC compatible ones.

[Robin Davies-Rollinson]

I for one have just switched in the xvYCC function on my Canon HFS100 and will keep it activated.
Time will tell if I see much of a difference, but it's not going to hurt anything having it in use...

[Dave Blackhurst]

I've left the xv color function "on" on my camcorders, on the basic theory that it can't actually hurt anything. While the manuals say that an non-xv TV might display some odd colors when displaying xv recorded material, haven't heard or seen it myself, but I guess it COULD happen.

IMO it's a "non-issue" unless your subsequent processing can do something with it, but more data points are alwyas better.

As far as no responses, everyone is focused on the holidays, you don't actually expect us to THINK too hard right now do ya? I'm in a cookie induced sugar coma myself - brain may be back in two weeks or so! Plus, I'm not sure there's really much to discuss - turn the function on, and you should in theory get a wider colorspace to work with - videos look a tiny bit better to my eyes, so "on" is good enough.

Similar to the thread you started on extracting enhanced detail with higher bitrates, I'd say "your mileage may vary". EVERY element in the production chain has potential for optimization (or epic fails!), the deeper the understanding of your equipment the better, but you really can't get too tied up about it!

[Jack Zhang]

My HC7 has the xvYCC recording feature, but the reds come out entirely inaccurate in that mode. Other cameras with better color rendition might do better in this mode though.

[Victor Wilcox]

I've been shooting with the x.v. gama with my NX5U since I received it in October. I don't have any comparison with other settings but I love the results. I've been using a Samsung BC-C5500C Blu-ray player on a Samsung 52" HDTV. I'm not at home now, and don't remember the model number.