Just to calm your fears Convergent Design have been around for some time and are well known for producing some of the better, more robust production gear. I like the fact that they are an innovator with an ear close to the market.

Hi Alexander-
Thanks for the correction. We don't have a white paper on the CODEC in Flash XDR, but I can tell you that we use the very same CODEC as the new Sony 4:2:2 camera. (We buy a module directly from Sony). We actually have two MPEG2 CODECs chips on board, so we can support 4:2:2 (a single CODEC will only do 4:2:0).

Since we record to Compact Flash, we can easily adjust the bit rate over a wide range of 19.7 to 160 Mbps. Rates over 100 Mbps will require the higher speed Compact Flash cards, such as the SanDisk Extreme IV.

I really suspect the sweet spot for recording will be the 100 Mbps 4:2:2 in either Long-GOP or I-Frame mode. Then you can use the lower cost Sandisk Extreme III cards (16GB cards are now around $200).

We plan to post comparison video at the various bitrates so everyone can evaluate the quality differences.

Mike Schell

So this wasn't an example of any actual video footage, just a demonstration of the limits of various chroma formats? If so all that tells us is that it pays to edit in a 4:2:2 or 4:4:4 format, which you can do with footage from any HD or SD camera.

To simulate how footage from different cameras might compare, I created a 960x540 image in Photoshop and added a small dot, then resized that to 1920x1080 and added another dot of approximately the same size. I'm not a chroma-keying expert but I have a feeling the dot on the right would be easier to work with...

http://www.videomem.com/temp/two-circles.jpg

Mike: since the Extreme III cards are supposed to support sustained write speeds of 20 MB/sec or 160 Mbps, can you go beyond 100 Mbps reliably with your device on those cards?

Yes that is exactly what this image is for. This image shows the perfect example for the best outcome. No video camera can ever be this sharp or detailed. It doesn't matter if you have 4:2:0 from a computer image or 4:2:0 from a video camera they are both still 4:2:0. In fact with a video camera you may not even notice the edges as much because everything has smooth details.

Keying also doesn't matter with how soft an edge is. only in bad keying is this a concern. A good key means the edge looks natural as if it was shot that way with a camera. If you zoom in and look at the edge of any footage you will notice how the edges have gradation and are not pixel sharp. Again no camera shoots perfect pixels. When you do your key you want the edges to look as close as possible to how they looked before you did the key. So in your image the soft dot wouldn't be any harder to key then the sharp dot. They would just have different looking edges. If your camera shoots a little softer then you want to keep everything that way so the key edges have the same look as if you shot that person in that environment. This is why for visual effects a lot of times we turn the electronic sharpness totally off on cameras and key that way. It gives a more natural look to the edge because camera sharpness can create fake looking edges. In fact in terms of chroma subsampling your sharp image would be harder to key because the 4:2:0 would show up even more because of how sharp it is. If the edges were softer the color change would be softer and not a sudden change. This i why shooting 4k is so nice with Red. Red shoots some pretty natural but soft images because it takes the image right from the chip without any edge enhancement. 4k allows people to work with the softer images but they still have a lot of detail because they are so large. the edges are still nice and soft and natural.

That would certainly be true for any camera which doesn't have a 1:1 mapping from the sensor to the recorded and output video formats. The EX1 solves this problem, except to the extent that interlacing affects the image. That's the point of my example: the recorded image from the EX1 potentially could be that sharp.

Maybe I'm missing something, but I don't see how video with blurry details would be easier to chroma-key than one with crisp details. Isn't part of the point of chroma-keying to identify the edges?

No the point of keying is to put something somewhere where they were not. The art of compositing is that your final result should look exactly how it would have looked if you shot that person in that environment. The more crisp an edge the more you will notice low chroma resolution. It also depends on the quality of the keyer software. Some simple keys yes they only works in single colors so a harder edges will give you better results but these are not great keyers. They leave the edge looking fake with no smooth edges or even motion blur for that fact. Real video and film has motion blur and a good keyer should be able to deal with that. I hear some people talk about shooting with a high shutter speed so there is very little motion blur but that isn't very realistic. If you shot your actor in that environment would you have shot it that way? Sure the edges of the key may be clean with cheap tools but it is fake looking.

With the proper keying tools the softer image will look more natural unless the camera really was that sharp. No the EX1 will not be that sharp either. Even the F950 isn't pixel perfect 1:1 sharp. Video has to have low pass filters so the video doesn't have aliasing. Interlaced has to be filtered even more to reduce interlace flicker. Even photographs are not super crisp like computer graphics. The image I made is about as bad as you are going to get with reduced chroma resolution.

In which case I don't see a problem for the EX1 when used in progressive recording mode, as the third image in your example looked fine without magnification - only the interlaced example really stood out as having issues. So running the EX1 in progressive mode and editing the resulting footage in a 4:2:2 color space shouuld work pretty well for normal viewing circumstances.

Hi Kevin-
We won't know until we do a lot more tests. The 20 MB/sec assumes sequential writes, which is possible 95% of the time using the MXF OP-1A format. We do have some non-sequential writes that must be performed even with this fomat (header info). Also, you need to allow some extra margin for audio data, header info as well as updating FAT tables and opening / closing files. So, we rather quote a more conservative figure until we can do more exhaustive tests.

The good news is that Compact Flash write / read speed does not degrade as the card fills up, unlike hard-disk drives.

Mike Schell

Thanks Mike. Do you have a standard recording option with a bit rate somewhere between 100 Mbps and 160 Mbps, or is 100 the main conservative choice?

I agree 100%. That is why I posted the images. progressive 4:2:0 is a very clean format for keying. Sure it isn't perfect but it is pretty darn good actually. I forgot what editing system you use but if you have a way to soften or up sample the chroma then it will be even better yet. By the simple chroma soften filter I used the edges look just as clean for all the formats. Of course if you use a XDR you may not have to use a filter which means no darker edge and footage you can work with right out of the box.

One other thing to keep in mind about interlaced 4:2:0 is that it works out pretty good if you plan on keeping it interlaced. Each field gets played one at a time so the alternating samples do not show up when played back that way. That is why 60i 4:2:0 keyed as 60i 4:2:0 may look bad in the NLE but it should be fine once it is played back on a TV. Well it isn't perfect but much better then what we see here. The problem with interlaced 4:2:0 is when companies try to put progressive frames in a interlaced mpeg2 file such as the Canon HV20. So for those who want to shoot 60i as 60i the 4:2:0 should be fine although I personally would prefer 4:2:2 for 60i.

Michael - I would be strongly advising against the EX as a replacement for 35mm film. There is no doubt the EX is a revolutionary handycam, but at best it still has many of the limitations of a handycam - not the least 4:2:0 or 4:2:2, but how about a fixed lens? half inch DOF as opposed to 35mm? CA that you would only find on cheap 35mm lens, etc. You could consider it as an option where lugging around a 35mm kit was impossible.

I really think RED is a much better match for what you are doing - it's more expensive, but you gets what you pay for - and I don't know how much shooting you do but it would surely pay for itself fairly quickly. It a full sensor, with a 4:4:4 post workflow pretty much designed and working.

If you are unsure I would rent first, decide later.

I've said elsewhere that the absolute number of chroma samples isn't the determining factor, but the ratio of chroma samples to luma samples. Thus the choice of terminology being expressed as a ratio.

So, by this measure, 3:1:1 should give a better key than 4:1:1 or 4:2:0. 4:2:2 is better than 3:1:1. 3:2:2 (which to my knowledge has never been used) would fit between 4:2:2 and 4:4:4. 4:4:4 and 3:3:3 (another format that is, to my knowledge, mythical) would be exactly equivalent.

On second thought, calling 3:3:3 mythical is off the mark. We use it often- we just call it 4:4:4.

But 3:1:1 wasn't good enough for Star Wars.

They recorded 4:4:4 off the head to outboard decks. (D5-HD decks I think.) That said, I bet there were some shots where they said "heck with it, pull the cables." Then HDCAM would rear its head.

For Star Wars 3, Sony delivered HDCAM SR. I think the dual link HD-SDI spec was developed to fill the technical needs for Episode 3.

I see we are agreeing contentiously.

4:2:0 isn't garbage.

There are a lot of circumstances where 4:2:0 will work very well. Even the interlaced version can work well for some productions.

In the end what I am deeply concerned about is for most users an edge case. (pun sadly intended.) Most stuff that people shoot and need keyed will be far simpler.

4:2:0 is inferior color sampling to 4:2:2 in all cases. In many productions it won't matter. 4:2:0 will produce exemplary keys.

When it does matter, the difference will be pronounced.

Because I like to throw wrenches into the works, I will add that 10bit vs. 8bit is a more important consideration for a lot of post workflows.

It isn't building the tree that I think takes time. Tweaking all the parameters of all those nodes for best effect is what I think will suck up artist time.

On the render side- the built in nodes are much more efficient than scripts we build using the interface. The fewer nodes we use the faster our renders will be.

So, its a double whammy.

Now that we've beaten this horse to death, I'd just like to say that proper planning, the right tools and smart craftsmanship of the image can do way more to make the image work for audiences than just about any technical detail.

I agree that wavelet compression is the next big thing.

I disagree with the long term outlook.

The question isn't whether or not most of my wishlist will come to pass, but rather when.

Storage is getting cheaper, bigger and faster very quickly. Let's have a trip down memory lane. (once again I intended that sad pun.)

http://www.pcworld.com/article/id,127105/article.html

http://upload.wikimedia.org/wikipedi..._over_time.png

1956 IBM introduces the hard drive, with a 5MB drive the size of two refrigerators.

1980 IBM brings us the first 1GB hard drive... at a weight of 550 pounds and selling for a paltry $40000 USD.

1991 IBM Brings us the first 1GB 3.5" drive.

2001 Western Digital's 100GB drive sold for $449

2007 HITACHI, the former IBM Hard Disk division, introduces a 1 TB drive. You can buy it now for about $280

http://www.bestbuy.com/site/olspage....ci_sku=8295588

I predict, by extrapolating these curves, that we'll have 10 TB drives by 2011. By 2021 we'll have 10 Petabyte drives. That's 10000 TB- the same 1000 time improvement we got from 1991 to 2007. Basically I am betting on Moore's Law and its analogues in storage tech.

The exact numbers don't matter much. I'm going to simply assume that we eventually get a 1 petabyte drive.

A little fast envelope math. Uncompressed 10 bit 4:4:4 HD SDI dual link is about 3 Gbps. 4k is about 4 times the pixel resolution of HD and thus four times the data. (Yes I know its a bit larger but 2K and HD 1080p are pretty close in a 16:9 format.) 8k is about 4 times the resolution of 4K so...

Uncompressed 8K 16:9 video at 4:4:4 10 bit should be about 48Gbps. My 16 bit log version should run about 77Gbps, I'll round that to 10GB/s. That's 1 min 40 seconds minutes of storage per TB. I am going to round that down to 1.5 minutes per TB to handle various overhead in the file system etc.

That's 1500 minutes per petabyte. 25 hours of uncompressed 8K 4:4:4 16 bit footage.

Now to accomplish all this we need drives that write a sustained minimum of 10GB/s. That's about a 600 fold increase in speed from today's. (A lot of single SATA drives transfer about 1GB a minute. There are faster drives, but I'm using that number for the basis of my math.)

So when we first get Petabyte storage around 2015, in an array of say 7 150 TB drives, we'll be dependent on RAID-0 to get the speed we need.

By 2021 I think we'll be able to stretch a smaller 2-4 disk RAID 0 volume to do the job.

By 2030 A single drive will handle 1PB at uncompressed 8k 16 bit 4:4:4 with hours of storage.

We live in a weird place technologically. We live where compression is required to get basic video work done for most people without exorbitant budgets. We live where storage space is an issue.

This will be a historical anomaly, most of history will be recorded using standard uncompressed video formats on standard and highly reliable media.

Today, we struggle without those future standards, and we struggle to invent them.

Apple however can be counted on to provide us with a low end laptop and a high end- with no middle of the range. To think otherwise I maintain would be madness. (Not that I would mind a bit of madness... in case anyone at Cupertino is reading this.)

Interesting
 

That's very informative. So maybe NASA will be shooting with Red 8k digital video from the moon by then. Ultra Hi rez images of a gray and tan surface.

Cheers.

And somewhere between now and then most movie theaters will probably switch to digital projection using some lesser form of compression, meaning there will be little need for that level of recording quality. And more people will be watching their movies on home TVs or portable video players requiring even less quality, although it never hurts to have high-quality source.

But as far as the EX1 is concerned, the native 4:2:0 will be fine for many of us and the 4:2:2 option with the Convergent XDR recorder should be awesome. If you really want 4:2:2 recording either buy an HD-SDI recorder or a more expensive camera, or settle for marginal resolution with the HVX200.

OK, I get it- yanking my chain. I'm laughing. :) I get that I'm off in la la land when I do that, but I find it amusing- I hope you do too.

Space scientists would love nothing more than to see these sorts of images projected so they can really stand on them. Of course... they may as well be black and white for lunar images, but on other bodies full color would be useful.

Theaters survive by providing a better experience than people have at home. I'd ask if that will remain the case in the future. I suppose it will because, ostensibly, theaters can throw more money at the problem of presentation fidelity.

I also think we are headed for high resolution displays. For computer use, as an example, 30" displays are the largest useful to most people. At that point you have to turn your head to see the entire image in desktop use. If you need more screen real estate you might as well use additional monitors.

The trend will be to increase on screen resolution- driving dots per inch towards resolutions like we see in the print world. I think Microsoft and Apple agree because they are building resolution independence into the OS.

Instead of a 320*480 iPhone I expect that I'll have 1920*1200 in roughly the same size screen, thus raising the screen resolution from 163ppi to a laser printer quality 620 ppi.

I question the value of that trend for motion picture applications, but I see that it will be incredibly useful as someone who reads a LOT on computers. (Just as I like reading higher resolution printed pages.)

Regardless of whether its useful to the viewer, that technology is coming- and we have to start thinking about it. Will we just upscale our current images... or will we all shoot 4k and higher resolutions?

I agree that recording quality should exceed presentation/delivery quality by as much as practical. In an era of such incredibly high, by present standards, resolution what will contribute to quality?

Nice way to lead this meandering fool back on topic. :)

I agree that 4:2:0 will be enough for most projects. I think it may well be enough for most scenes even in a film that will endure a great deal of post.

Unless you are shooting a visually stylized piece like 300. All that post contrast and crushing makes for evil contouring in 8 bit footage. (300 was shot in 35mm and scanned in a 16 bit log format- .dpx I think.)

Now that I've looked more into the Convergent Design Flash XDR I think it will be a great product. My problem with it is that it records 8 bit formats.

I think that for my technical film style work I'll have to choose a 10 bit solution- 10 bit matters more in DI than 4:2:2 I think. I'm kind of bummed because I was getting excited about the Flash XDR. I am considering one for a B camera, but I think I'm gonna go with the AJA ioHD product on A cam- even though my total solution will cost much more that way and be more of a hassle to set up on set.

Check out the CineForm Software Showcase. They are talking about making a 10 bit mini DDR. Let them know what is important to you.

I'd say it's the already case that in some ways you can get a better viewing experience at home, so theaters are mainly surviving because people like to get out of the house once in a while. With millions of households owning HDTVs and now starting to buy HD disc players, the quality of the home viewing experience is increasing while the experience of going to theaters is arguably declining with all the ads and previews and other distractions.

One good thing about the EX1 is that it records at close to the maximum quality most people are going to be able to see outside movie theaters, plus you could potentially archive the master footage on Blu-ray discs and be able to play those. This is a handy coincidence for anything besides big-screen distribution, and should make it a good camera for projects going directly to customers (both home and corporate).

Kevin;

You cut my quote short...

So my argument is based on the fidelity of presentation. So we aren't talking about the same thing.

I agree with your point, but I think that ultimately there has to be a reason to do any particular thing "out of the house."

You might choose a restaurant, because of the service, and perhaps because they might be cooking something you can't, or are too lazy, to cook for yourself.

Theaters get chosen because the projection looks and sounds better than people get at home. Enough so that people are willing to put up with all the other problems.

I would definitely agree that the gap is narrowing, and that many moviegoers will not be able to appreciate or even perceive the differences as a result.

I agree and disagree.

Some people can't tell the difference between VHS and DVD, and the change from DVD to HD DVD is far subtler. That isn't to say I think its subtle. My point is that some people are apparently using sonar to view films.

Film projection, when done well, is so much better than HD DVD playback that it isn't fair to compare the two. Digital projection pales to well done film projection, but is actually far better than film projection at your typical multiplex.

OK, I am going off track. The point is that there is a marked improvement in sound and picture fidelity in theaters.

I agree with the distractions you mention wholeheartedly. I think that theaters will get smaller as a result.

4-20 seats. You'll reserve them with your own private group and watch whatever movie you want. Possibly with dinner served.

So, the theater business will change, but there will still be a theater business.

Well most HD TV's are actually 720p, so for many of your HD capable audience the EX1 exceeds the resolution of their setup.

You may have noticed however that "Hollywood" DVD's typically look better than most videographer's DVD's. A lot of that is accounted for in the craftsmanship, but a non-trivial amount of that improvement comes from film.

We are going to notice that a camera like the EX1 gets us closer... and may even match the "Hollywood" look for DVD or other SD release... but on HD DVD or Blue Ray there will still be a gap.

For some reason those people in Hollywood keep making their stuff better just as we improve our stuff. Go figure.

That plus the novelty of seeing movies when they're first released, which is the main reason I bother to go to theaters any more. If first-run movies were released simultaneously on DVD the theater attendance would probably drop significantly, which of course is part of why that isn't done. And if quality was the main reason people go to theaters, shouldn't more theaters and movies be IMAX by now? I agree that projection experience is a factor but not necessarily the only important one - I'll take the comfort of my living room over a movie theater most days.

P.S. Sorry about not fully quoting you.

And you guys win the award for the going the most off topic today.

<picard voice on>
Agreed.
</picard>

I talked about this with Mark Cuban, and I suggested closing the window all the way, DVD, HD DVD, Blue Ray, Pay per view- all out on the same day as the various theatrical formats. He didn't immediately call me an idiot, which from him is a compliment.

Use a sliding scale for prices... so that an opening weekend DVD might be $100 to buy, and an opening weekend HD DVD might be $300. Slide the price down after the film closes in theaters until it reaches a price near the current average.

You sustain the model by building value add into the pricing. If you buy an opening day DVD, then there are no special features. In truth most of that stuff is still being posted when the movie is released anyway.

Later, around the time DVD's would normally be released, you put a special edition out there that contains the extras we get on DVD right now. The early purchasers get the new package (which they have already paid for in fact) by trading in their old discs.

What about piracy? All the discs are watermarked. Forget any actual copy protection, just alter key scenes of the film with unique identifiers- like they do for film prints. If a pirate version surfaces we all know who purchased the original. In other words replace restrictions with accountability.

That's just a rough sketch... there are a lot more details. Still you can see where the idea went. (i.e. nowhere)

No. Remember that most theaters are in the candy, popcorn and soda business. They don't care about movies except insofar as they get you in the door to buy candy, popcorn and soda.

IMAX is expensive in terms of real estate and projection equipment.

The trend I think we are seeing is digital projection. Most theaters have very badly maintained and operated projectors. Don't even start with the issues of film degradation. Digital is a huge boon for theater owners, because it more reliably gives the same performance over and over, reduces maintenance and labor costs.

Before that we saw THX and Dolby certifications for theaters. Of course that was only because it drew in more of the folk who wanted to see the summer blockbusters.

Still.. to even get that much care for image quality from NATO, studios have had to share more and more of the gate. Studios do that because a lot of their follow on sales (cable, TV etc.) are structured based on the performance of the film at the box office.

No worries, so long as we eventually talk about the same thing I'm good. I want to talk to you not at you.

Besides in this case it led into an interesting place. As everyone can see, I love to meander along and let conversations lead wherever.

So, Thomas- I suppose I'll win that particular award quite a few times.

I'm always happy to move to another forum if its more appropriate... just too lazy to actually start that process. Still if you build it I'll meander appropriately.

Which is called hijacking a thread, because we don't care about those people who came here looking for a technical discussion about 4.2.2. versus 4.2.0 -- but it doesn't matter much anymore since it's been pretty well beat to death at this point. Closed and locked,