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SONY 4K projector May 1st Redcode vs JPEG2000?

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Nik Manning

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http://www.engadget.com/2007/04/25/sonys-cinealta-4k-digital-cinema-solution-coming-may-1st/

Looks like Sony is releasing there 4k projectors May 1st. It is huge! Super huge, but what I wanted to talk about was their encrypted JPEG2000 format. It takes 300 gb for a 4k movie. Seems to me redcode is more efficient so is there away to make redcode encrypted for something like this? That would be a marvelous workflow to just go back to redcode as the final viewing format.

When Red says they are making 4K projectors are they talking for home , studio , or movie theater usage?
 
REDCODE leverages RAW, which is great for capture, but useless for delivery though....

We're not talking about the projectors other than we're working on them...

Graeme
 
Yup, making it efficient for capture, but useless for delivery.

Graeme
 
What about REDCODE RGB? In camera data rates may be optimised for the ultra-clean images from the camera, but could it not be used at higher data rates for editing and delivery?
 
Depends on the advantages REDCODE RGB can offer over DCI JPEG2000, remember bit-rate advanatages (if there is any) is not a compelling reason for the D-Cinema market (and E-Cinema its name for non-DCI formats.) We know a lot about this as CineForm Intermediate just got picked up for a theatre presentation format in India (press release should be out in a week or so.) Our data rates and quality are very similar to DCI JPEG2000, but our player and encoding costs are significantly lower (no hardware required.) If REDCODE RGB is unique in other compelling ways then maybe it could be a theatre format.
 
There's lots of possibilities in this market due to the DCI spec being a bit silly and way too expensive. It was really designed for film scans, not digitally acquired material.

Graeme
 
Yes, they did muck up the price somewhat....

Graeme
 
Data love

Data love

Graeme's comments about the DCI spec echo others I have heard. Now we find ourselves, as proponents of end to end data based solutions, in a tough spot. Do we:

A) Promote a better alternative to the current DCI spec that would have better image quality, similar or better compression rates and require less expensive infrastructure (easier authoring would be nice). Sounds great but it seems likely to only further muddy the waters with the stakeholders in the distribution chain and fuel the criticism that constant format changes make digital solutions too risky.

B) Accept the DCI specs, even if they aren't that great, just to keep momentum for digital workflows all the way to the screen.

Coming from the indie perspective I am willing to accept the burden of the DCI spec just to engineer out the costs of film and/or tape decks.
 
What's the issue with the cost of DCI infrastructure? I'm familiar with some of the technical aspects of the spec, and I can't see a good reason why I shouldn't be able to output a DCI spec movie on the desktop. Are there crazy licensing fees or something along those lines?
 
There are not really many tools to make a DCI package, and it's slow work. Nothing a desktop PC can't handle though.

Also, they use XYZ, which is utterly silly. I know why they did it, but their reason doesn't make any sense at all. It just wastes code values.

The DCI projectors cost way too much, and if they're anything like our Sony 4k, they're a right pain to use.....

Graeme
 
Graeme Nattress said:
There are not really many tools to make a DCI package, and it's slow work. Nothing a desktop PC can't handle though.

Also, they use XYZ, which is utterly silly. I know why they did it, but their reason doesn't make any sense at all. It just wastes code values.
Click to expand...

They used XYZ because they wanted some degree of future proofing in the event that new capture and display devices are developed (probably electronic) that exceed the color gamuts of current devices.

There may be issues with the DCI spec (or with SMPTE DC28, it's more "official" standards committee), but the spec is actually quite a bit more flexible than many people realize. For instance, the use of 24 fps is not mandated. Other things are left a bit open as well. But I don't see anything else out there that allows manufacturers to create devices that will work with what the studios are going to deliver, and I don't see anything else out there that will allow D Cinema to move forward - because there has to be a standard before theater owners are going to waste money investing in dead end technology. For better or worse, the standard is here, it works (you were at the Digital Cinema Summit, so you saw what I saw), and it's not that tough to comply with. It covers 2K and 4K projection, and it covers pretty much all the current needs for theatrical presentation, including multiple audio formats, subtitles, and, yes, encryption and security. It's also much better than having theaters (and festivals, for that matter) put in HD projectors and play back HDCam videotape. The best way to improve it is probably to get involved with the SMPTE DC28 group and make relevant suggestions.
 
XYZ is wasteful though, as cameras and film don't produce that wide a gamut. The sensible approach would be to tag your RGB colour space with it's white point and chromaticities, and let the projector convert from the source space (which could be XYZ if it's CGI, or sRGB, REC709 or... Whatever) and convert to the projector RGB space. At the moment, you take your RGB and convert to XYZ, and then the projector takes that XYZ and converts to it's RGB. The reason given is that if you mandate XYZ, it eliminates the need for metadata, but given the rest of the spec all relies on metadata, this is a moot point.

By encoding the image in it's source colour space, rather than the super-wide XYZ, you maximize use of code values and will probably get better compression / precision by doing so, so the point isn't completely academic.

XYZ was chosen as not to limit the gamut. However, this means as projectors get wider and wider gamut, they might start displaying colours you didn't know were there, and things might look different. We can't monitor XYZ directly, so we can't easily check. You can't look at the master in it's native space without it looking totally whacky.

Basically, I think the tagged colour space solution is a better one than the XYZ solution, which just confuses people.

The image formats of 2k and 4k are designed around film scans and ignore the fact that there's a lot of 16:9 material being produced. That doesn't seem clever.

The only fps mentioned in the spec are 24fps and 48fps (2k Only), which to me, is limiting. There was a good question at the event about multiple fps in the same project, which to me, is a good question as you've got to look at world markets and the preponderance of 25fps and 30fps material out there, and especially documentary movies that could benefit from this.

I could go on, picking holes here and there, but quite frankly, it wasn't designed for digital origination.

Graeme
 
Graeme Nattress said:
XYZ was chosen as not to limit the gamut. However, this means as projectors get wider and wider gamut, they might start displaying colours you didn't know were there, and things might look different. We can't monitor XYZ directly, so we can't easily check. You can't look at the master in it's native space without it looking totally whacky.
Click to expand...

While that is indeed true, the current result seems to work pretty well, remarkably well in fact, especially given that the material is always going through two color space conversions with a middle step that can't be monitored. But the math generally seems to work, and I think perhaps the future proofing is a good idea, even if it presents limitations in terms of total image fidelity for today's formats.

The image formats of 2k and 4k are designed around film scans and ignore the fact that there's a lot of 16:9 material being produced. That doesn't seem clever.
Click to expand...

Clever, no. But it does serve the needs of those who wrote the spec in the first place - as a very intelligent speaker brought up during the summit (I think that was Marvin from Modern Videofilm). I agree that this should ultimately be modified, but as was also stated, the spec is still a bit of a work in progress, not something set in stone. Thus the need for more voices of practicality in the SMPTE committee.

The only fps mentioned in the spec are 24fps and 48fps (2k Only), which to me, is limiting. There was a good question at the event about multiple fps in the same project, which to me, is a good question as you've got to look at world markets and the preponderance of 25fps and 30fps material out there, and especially documentary movies that could benefit from this.
Click to expand...

While that's also true, the way the spec is written it's a bit more vague than it may appear. It uses terminology such as "up to" instead of a direct specification, and according to others who know more about it than me, there actually are provisions in the updated spec (i.e., the unfinished DC28) for 25fps projection. Having said that, I also thought the question about multiple frame rates was really brilliant. And I'm not saying that just because I was the one who asked the question :biggrin: ...
 
1- Re: 2K resolution
To plagarize Charles Poynton's opinion... the 2048x1080 resolution has little technical merit to it, only marketing merit. They should adopt 1920x1080 resolution since there's economies of scale behind it (i.e. in projectors... Sony's 4k projector I believe is 4 times 1920x1080). And when you version for DVD (which practically every theatrical release will), it's simpler because you don't need to rescale or crop.

Too many formats is a bad thing.

XYZ is wasteful though, as cameras and film don't produce that wide a gamut.
Click to expand...
From what I understand, digital cameras can produce XYZ gamut (ignoring color accuracy). Certainly in color grading, increasing saturation will push colors outside their normal gamut. Or you might introduce special effects with wide gamut colors... i.e. lasers in scifi movies.

2- As far as monitoring wide gamut...
Yes it will be challenging. However, there are ways to visualize colors that your monitor can't produce. You can for example lower saturation on everything so that you see the relationships between colors, have your system highlight all out-of-gamut colors as yellow or whatever, etc.

As future systems get wider gamut, the colors will (chances are) look better. So you could say that certain colors will shift hue as you get wider... but to me, that's not a big problem. Color accuracy is not that huge a deal because we generally don't notice it / filter it out (the real world isn't color accurate to begin with).

I would think that your real problem is with projectors that are smaller gamut that what the colorist saw. Bad gamut mapping can degrade image quality in ways you don't forsee (i.e. if you just let colors clip after you use a matrix to adjust the colors, you get shifts in luminance; this looks pretty bad).

In a similar vein, you could argue that going with wide gamut removes the WYSIWYG-ness of color grading.

3- On the other hand, you could argue that it's a better idea to stick to a fixed gamut. You have financial and technical limitations so you gotta pick your battles. For marketing and aesthetic reasons, resolution and contrast ratio make more meaningful impact on picture quality. Contrast ratio makes the biggest difference in image quality. Resolution is very marketable. 3-D might also be worthwhile (??).

Wide gamut isn't very marketable (difficult to show people, is not a simple concept, etc.) and doesn't make that big an impact on picture quality. In most feature film material, you just don't get a lot of extremely saturated colors that hit the boundaries of film gamut. And in de-saturated films like se7en, wide gamut doesn't do anything for you. If you consider that and the complexities of working in wide gamut (i.e. not being able to see out-of-gamut colors), then maybe it isn't really worth it to do wide gamut.

3b- I believe that even if your display device could do wide gamut, going with a smaller gamut would raise light output and let you increase contrast ratio. If you look at the original NTSC primaries, they defined a much larger gamut than current TVs. But it got abandoned in the race towards brighter output.

In theatres, you will have a pressure towards brighter output to get larger screen sizes, extend lamp life, (and I believe) or to get a higher contrast ratio.

Thus it might be reasonable to stick with a fixed gamut system (though you have to choose very carefully, not too wide or small).

That being said, I haven't really seen a wide gamut system in practice so I can't say about the image quality.

3c- In color grading there may be an art to making colors look very vibrant within a fixed gamut.

4- Compression efficiency:
I don't think this is a big deal. Just throw lots of bandwidth / storage at it... instead of introducing complexity or other problems trying to get size down.

5- Perhaps the digital cinema industry and the home theatre/video industry could sit down and have sort of a truce.
The digital cinema industry is trying to stay one step ahead, while the home theatre industry is trying to deliver theatre quality in the home. So you have things like DCI adopting 2k resolution so that they can market 2k resolution over 1080 (while 2048x1080 and 1920x1080 are practically the same, and might actually be the same because it's cheaper to post in 1920x1080). That's stupid.

And then in the home video side, they're adopting wide gamut color because the digital cinema folks are doing it. But the home video side will likely have a lot more trouble implementing it due to backwards compatibility and needing to apply color management (mapping out-of-gamut colors into displayable colors). Color management done poorly won't look very good (and it's likely this will happen because you need to keep costs down in consumer equipment).
 
Some pictures...

In the first attached image, I increased saturation (via chroma gain) to create colors outside rec709 gamut. These colors aren't color managed. Clipping occurs and this results in shifts in luminance (since monitors can't produce negative colors, or colors that are whiter than the monitor's white).

In the second attached image, rudimentary color management is applied (luma is kept constant). This brings out detail in the clipping areas... i.e. you see more folds in the red/magenta/pink shirt.

This is actually not a very good algorithm since the hue will shift. As well, the proportions of saturation are not maintained; saturation gets clipped. However, it does show that no color management looks crappy. And in consumer devices, this might happen to keep costs down / the engineers may not understand the specs fully so they let stuff like this happen (i.e. we currently have the rec.709/601 color inaccuracies, and the chroma bug in DVD players).

If home video went in its current direction (a fixed gamut), you can easily avoid the first situation. The colorist would be looking at image #1, and can do the appropriate color corrections to avoid it. But in a wide-gamut system, the colorist would see #2 but some home viewers would see #1. If the colorist isn't aware of what might happen to the image, then some home viewers see #1 (which just looks bad). And if the colorist is aware of what might happen to the image, he/she might do a grade like #2. Which defeats the point of wide gamut, since there really aren't that many wide gamut colors anymore.
 
GlennChan said:
1- Re: 2K resolution
And then in the home video side, they're adopting wide gamut color because the digital cinema folks are doing it. But the home video side will likely have a lot more trouble implementing it due to backwards compatibility and needing to apply color management (mapping out-of-gamut colors into displayable colors).
Click to expand...

There's theory and there's current and foreseeable future reality. That reality is that the primary method of presentation in theaters now and likely for some time, certainly worldwide, is film. Current DI practice is to use the color gamut of print film as the target for all color management in the pipeline, including the video deliverables. Having a wider gamut available means little if the primary presentation format isn't digital cinema, because it won't really be utilized until that changes. Right now, color management is applied in all DI work that maps the print film target gamut to Rec 709 for HD video delivery. It will be some time before that changes.
 
Hi Michael,
Could you please clarify what you're saying? (I'm afraid I'm probably missing some context.) As I understand it, you're saying that:
Grading is done towards the gamut of print film (since most movies will be seen with film projection). Therefore, there is little point in specifying a gamut larger than print film (or little point in grading for it) until digital cinema is more common.
 
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