Les,

Shooting in 24p and outputting to HDMI, you're getting true 24p, spread out over 60i. What's happening is that telecine-style "pulldown" is being applied. This means some frames will be spread out over fields. I don't think there's a HDMI (or HDV) standard for 1080p @ 24fps, so they're forced to use this hack to remain compatible. Unfortunately, 24p was not really on the radar a million years ago when all these standards were agreed upon.

To remove the pulldown, you should be able to use Compressor. I'm not sure whether Compressor will be able to determine the cadence automatically or not -- if it can, it may be as simple as using the Deinterlace: Reverse Telecine option. That's how it works with 24p HDV. If that's not an option, you may have to involve Cinema Tools (?).

I'll see if I can find out for sure.

The timetable for the dvmatte release has been pushed back slightly -- unfortunately, it's sort of out of my control. Right now it looks like we may release at Macworld (January)...

BTW, on the subject of image settings... I learned the hard way that you don't want Color +1 when doing greenscreen. It looks good on-set, but it's really pushing the green in an unnatural direction. Color -1 works much better.

And definitely remember Sharpness -1, and Contrast -1. Those are key.

Les,
Apple has a technote on a good workflow for removing the pulldown, or "inverse telecine." You will end-up with true 24P. 24, full resolution, discrete moments in time.

- As already stated, both the HDV and HDMI standards necessitate encoding into a 60i stream. Except for a few oddball cameras and situations, 30P isn't really used anywhere. 1080/60i or 720/60P are both HDV standards.

- It's actually nice to have the 60i option, even for "film" work, because you can use it for some pretty nice slow-mo effects. (you give up some spacial resolution due to the interlacing, but the temporal resolution more than makes-up for it, IMHO.)

Ben - My real concern is with the uncompressed HDMI output while recording 'live'.

1. Is the 60i from HDMI 'live' composed of 60 distinct fields from 60 different points in time (not progressive at all). Is what I'm after really 30p - that when you say 60i this implies the frames are all from distinct points in time?

2. Does this differ from the HDV 24p packaged in 60i? With 24p, are there matching odd/even fields making up one frame from one discreet point in time (with dropdown added) - truly progressive - or is this 'simulated' 24p, where the odd/even frames are not from the same moment in time?

3. For dvMatte Pro, will there be a beta release? Will this be a version upgrade where if I purchased now, I'd have to pay more? Will it work ok with the 4-2-2 colorspace from direct HDMI capture?

Thanks!

Yes and yes. You want 30P, and the HV20 does not have it. Nor does almost any camera.

Yes, this is different. You will get 24 full, true, progressive frames if properly decoded. I promise, but you don't need to believe me. Just download some 24P footage from the camera and look at it frame by frame.

Joseph - if I'm shooting green screen of a subject with a lot of motion. Will I get better results with 24p packaged in 60i:
advantage true progressive, so de-interlace would work perfectly; disadvantage less frames per second, 4-2-0 color space, MPEG compression artifacts

or HDMI uncompressed at 60i
advantage 4-2-2 color space, no MPEG compression, higher frame rate; disadvantage fields cannot truly be de-interlaced properly as they are all different moments in time?

Thanks!

No, Les, the 24P is "packaged" inside of 60i whether you record to tape with HDV or if you stream out of the HDMI port. (This is called "telecine" and it's a very old, proven technique.)

You can go out of HDMI and get all of the quality benefits for keying. All you do is make sure the recording mode on the camera is 24P and you're good to go. Again, you have to decode the 24P out of the 60i stream, but it is true 24p not a 24F hack.

I hate to confuse you any more at this point, but there is one caveat about the HV20's 24P encoding. The camera does not flag which fields go with which frames, so you have to be careful to use a tool that actually analyzes the image and finds the start of the 2-3 "cadence" that defines the 24P frames.
(Cineform's capture software can actually do the inverse telecine on the fly, but it is a PC only option at this time.)

Joseph - I understand you to say that I can capture 'live' thru the HDMI in 24p, skipping all the MPEG compression and getting 4-2-2 color space.

Or, are you saying you can capture 24p thru HDMI of previously recorded HDV - in which case there is no advantage to using HDMI over Firewire. That the 24p will be 4-2-0 and MPEG compressed no matter what.

Thanks!

Sleep easy, the 24P is nestled safe and snug (prior to nasty HDV compression) inside the 60i, 4:2:2 HDMI stream. It looks gorgeous.

Once it is recorded to tape, though, even if you go out the HDMI port, it has been mangled. This only works for "live" capture.

Joseph - YES! That is great news.

BTW - if you are on Final Cut Pro, what is the best way to de-interlace and reverse telecine the 24p captured using HDMI? My capture format is ProRes 422 HQ.

Should I just follow the Apple tech note starting at step #2?
http://docs.info.apple.com/article.html?artnum=306389

Yep, if you have FCP2 that's about the most straightforward workflow.

JESDeinterlacer is a free tool that can also detect the cadence breaks and properly deinterlace, as well.

? ... What do you mean by this, Les?

I'm able to recover pristine 24p from the interlaced HDV stream...

Sorry, I didn't mean that the 24P was mangled, just that the image quality was. (macroblocking, 4:2:0 color resolution, high-pass frequency filter, etc.)

Oh, yes. I'm sure the HDMI looks amazing!

Ben - could you find out the pricing plans for the dvMatte Pro MacWorld release?

As the cat is out of the bag as to the forthcoming new version, it certainly makes sense to outline whether this is a free upgrade, if purchases after the announcement (as of now) are price protected, etc.

Else, new sales tend to dry up.

Also - one question. I often do keying in Photoshop for still photos.

Could dvMatte Pro be used to strip out the background of a green screen photo - so that I could get it back into a format where I could edit it in Photoshop without loss of resolution? There are lots of Photoshop users who use FCP. Might be able to get some sales for you on some of the photography forums I visit.

Thanks!

Les,

You're talking sales, which is definitely not my game. But I'm sure dvGarage can clear up some of your questions.

I can tell you for sure:

- It won't be a free upgrade, but there will be an upgrade path if you have a previous dvmatte. dvGarage treats past (and future) customers very well, so just drop them a note if you have a question.

- The release is getting close, so you should be able to buy now and get a complimentary upgrade by dvGarage when we ship. But email them to be sure, and that way they'll know in advance. Their goal is to make sure you're satisfied!

- The reason we're delaying the release is so that Alex can spend more time on the training which will come with dvmatte. I think it will really be worth the wait.

Regarding Photoshop... I have a stealth plan for getting into Photoshop. But I've said too much already. :)

Ben - great news about Photoshop. I'd be happy if I could just import a PSD into Final Cut, clear the background there, and then output back into PSD or some format Photoshop can read - but it sounds like you have something else in mind. Maybe just include instructions for keying an image from Photoshop and outputting back to photoshop (I use Windows XP, not a Mac for Photoshop).

I recorded 24p thru HDMI live from HV20 without problems. I'm sure you already do this, but please detect (or allow a setting for) 4:2:2 colorspace - as direct HDMI capture seems to be catching on. If you do a few examples with this, I'd have to believe the results would look better than HDV. Even if the potential user's primary use will be HDV, just seeing something that looks better from a consumer camera such as the HV20 might be a selling tool?

When will a watermarked trial of the new dvMatte Pro be available? That is what I really need to make my decision.

Thanks!

Les,

There's no good way to autodetect chroma fidelity, unfortunately. Besides, you'll want control over exactly how much chroma smoothing you want. The default settings look good for 4:2:2, but you can bring the default smoothing level down a few notches without seeing hard edges...

If you have access to a greenscreen, could you post stills from it in HDV and HDMI? I've actually never seen HV20 footage through HDMI. So far, HDV seems to be doing a good job -- the 4:2:0 is not a big deal, and I don't see a lot of compression artifacts. I'm curious to see what the benefits might be with HDMI!

And yes, we'll have a watermarked demo!

look here:
http://www.dvinfo.net/conf/showpost....48&postcount=5

HDV vs HDMI is just like night and day. I use HDMI output not only for greenscreen work, but for every indoor and outdoor shot as well.
The reason is: HDV footage looks like out-of-focus comparing to clean & crisp hdmi capture. So, if you've never used hdmi out, you've actually never really tasted HV20 -))

How do you use it for exterior shots? Lug the whole computer outside?

Thanks for the link! Interesting... The HDMI definitely has more resolution. Though I think I would take the hit in resolution when recording in the field... It's worth it to not be tethered.

However, it's a different story in the greenscreen studio. If you have a computer capable of taking the Intensity card and you do lots of greenscreen, it's easily worth the $250.

I am impressed with how well the HDV holds up, though. Brightly colored details do better with HDMI, but that's to be expected. For most greenscreen subjects, the biggest hit you'll take by using HDV over HDMI is the loss of a little resolution. The 4:2:0 vs 4:2:2 is not a big deal, and your edges should look similar.

BTW, this is with about 5 minutes of fiddling with dvmatte -- the results could be improved by spending a little more time with it. Also, having a shot of just the greenscreen without the subject would let me do a screen correction pass, which would make this shot look about a million times better. And I didn't bother trying to protect the almost-green ironing board, which would be keyable if the greenscreen wasn't so dark and blue...

Ben, great results!!!

Well, I still think an uncompressed version looks better (edges are cleaner, without 4.2.0 "jadges"). A main problem, at least for me, is pulling a good key out from hairs "on a wind". In my opinion, that kind of problem lies not in compression algorithms, but rather in not-so-perfect camera resolution (compared to F950, Viper or film negatives). What do you think, Ben - is it possible to create a good matte from medium and long shots of subgects with thin hairs?

And yes, I use HV20+Intensity for all exterior shots (a pair of 5kW generators, lots of lights, cables, monitors etc.. he-he, computer is such a small thing among all that stuff.. -))) Anyway, I'm wating for this amazing device from Cineform team: http://www.cineform.com/products/CineFormRecorder.htm

Ben - did Anton's images give you what you need for HDV to HDMI comparison?

I'm mucking around with light levels and want to have it all set up correctly before I post anything.

Trying to find the most optimum level for the HV20 (someone said 2000 lux was best level for HV20, but I need to confirm this somewhere).

And, the best level for green screen (I've got 2 dedicated fluorescents for the screen, 3 for the 'talent'.

All my light metering with a Sekonic has been for strobes, so I'm having to learn how to use it for video.

BTW - do we have to wait for MacWorld to try a demo version of the new dvMatt Pro?

Anton - do you have any tips for setting up the HV20 for best results thru HDMI?

What light level gives optimum results with the HV20's image sensor and lens?

Definitely! Of course, if you can zoom in or move the camera closer, it's always better, since you're utilizing more of the sensor. You can then shrink the subject to fit the frame. Of course, this doesn't help you if you need to have a figure walk from one side of the frame to another or something like that...

But whatever detail is captured in the shot can be reproduced. Getting a screen correction plate (just the greenscreen, no subject) is very important. Without it, you have to choose between detailed edges and uneven lighting on your screen corrupting the background...

BTW, the 4:2:0 "jaggies" are my fault -- I didn't sufficiently smooth the chroma channels in that shot...

Yeah, as I briefly mentioned, the HDMI shows an improvement, but it's not a quantum leap. Definitely worth doing if you have the resources (mostly for the small resolution boost), but it shouldn't keep you from shooting tape when you need to.

As for lighting: forget about Lux... And footcandles... And any objective measure of light for that matter. What you really want to pay attention to is the subjective reading of the HV20 -- use the photo button trick to get to the f-stop you want, and a shutter speed of 1/48th (assuming 24p). It's fine to shoot wide open, for example f/1.8 @ 1/48. If you can't get there, add light.

Hopefully you can monitor your set live, using scopes. The most critical thing is to get the lighting even, so pay attention to your RGB parade. You want the screen to be at 70% RGB (about 180/255, or somewhere around 70 IRE). That will give your screen some "headroom" to reproduce highlights.

I have some Rosco Chroma Green gels on order -- they clip everything but a big spike in the green frequencies of light. I'm eager to test them as greenscreen lights... They should give a much greener screen, regardless of the material...

Good luck!

What a beautiful idea! I've never tried it before (stupid me).
As far as I understand I should create a matte from greenscreen room, and then apply it as a 'background' to my key comp.
I'll definitely try it next time. I cherish a hope those ugly semi-transparent blinking hairs of models will be clearly visible. Thanks, Ben!

Les,
HV-20 is very hungry for light, I hate HV20's noise in shadow areas.
But don't overdo with lighting. You could use something like Adobe OnLocation to control an amount of light in realtime.
For greenscreen work, my background is lit 2 stops less than a foreground object (bg: 65-70% RGB)

Sort of -- your keying software needs to be able to incorporate the "clean plate" in its process. In dvmatte, it's a separate plugin. You apply the screen correction plugin (Screenfix) to your greenscreen footage, and then feed it a still (or movie) of just the screen, with no subject. Then you choose the color of the screen you want to equalize to. Screenfix then nukes your entire screen to that color, while retaining all edge detail.

You then have a totally even shot, and can pass this right into dvmatte. The results can be insanely good!

In my last post I mentioned wanting to be at 70% RGB -- I should have been more specific. What you really want is to be at:
R: 0% G: 70% B: 0%

In fact, 80% may be a better target unless you have tons of highlight detail (read: blonde hair) to deal with.

The shot that I used to compare HDV and HDMI had a widely ranging background, with a midpoint somewhere around:
R: 24% G: 65% B: 38%

...which means that there's only an average of around 34% difference between the green channel and the R&B channels. The more we can increase this distance, the better, because more difference translates directly to more subtle edges and lower the noise in our matte.

This is where I think the Rosco Chroma Green gels will be really helpful, by knocking down the R&B output of your screen lights so that your screen has no choice but to bounce green light back to you. You'll never get to 0% in R&B, but you should feel proud if you can get to:
R: 10% G: 70-80% B: 10%

If you can get that level pretty evenly across your screen, you should be able to make a simply incredible composite.

Ben - please post your findings when your green filters arrive.

I had thought of green filters also, but got negative feedback on the FCP forum (saying only needed if background is white) and would end up with more green spill.

But, it sure sounds like a great idea to me.

As to the "clean plate" - this is part of the workflow of dvMatte Pro?

I was hoping a watermarked version of the new release would get posted, so that I could try it out. Never hurts to have more feedback before going 'live' with a new release.

If there's more green spill, it will only be because the screen is greener! The greenscreen lights should always be flagged off and kept from directly hitting the back of your subject. It's also good to keep some distance between your subject and the screen, and be conscious of reflections... If your subject is holding a shiny metallic object and it reflects a pure green from the screen, you'll be stuck making a traveling matte for that area....

It's part of the ideal workflow. I know that most people won't do it, but those that do will come away with incomparably better composites.

Unfortunately, the beta cycle is over, but I will let you know the second we release the demo! :)

BTW, I posted the results of my gel testing on the following thread:
http://dvinfo.net/conf/showthread.php?p=784330

Bottom line: gels rule! I'll never again shoot greenscreen without them!

Ben - could you try this single frame?
 

Ben - here's a single frame recorded with HV20 thru HDMI live 24p to ProRes 422 HQ (reverse telecined using compressor as outlined in http://docs.info.apple.com/article.html?artnum=306389).

I'm the subject, and am curious how the blond hair can be masked from the green screen with your new tool. I understand blond and green is tough.

http://www.downloadfundraiser.com/m/singleFrame24p.mov

Thanks!

Les, blonde hair is extreeemely tough -- the whole new version was basically created to solve that one problem!

Here's what I could get from your shot. This would be assuming that you had a good screen correction plate. I hacked one together in Photoshop.

The result is not bad at all to my eyes! But it would be greatly improved by a brighter screen...

Ben - that looks great!

But, are you saying the green screen was not bright enough and you had to work on it in photoshop?

I was hoping to see what the results would look like using just the new dvMatte Pro.

If it would be useful, I could iron the green screen, turn up the lights (got to re-read this thread on setting the proper levels) and post a small clip with some motion in it.

BTW - I also did a Photoshop export of that frame from FCP. When I opened it in Photoshop (on a Windows XP box), it did not have an embedded profile.

Is there a way to assign one within FCP?

If not, what profile should I assign, maybe Apple RGB?

I'm also going to have to get my head around how to deal with the shift from Apple's gamma to the more universal gamma found on the PC.

No, I'm just saying I had to hack together a fake screen correction image. It's just an empty shot of the greenscreen with no subject, but everything else set the same as the main shot. With software, you can correct the background to be more even if you have a screen correction shot. I've attached the image that I cooked up.

I took that and the image you posted and ran it through dvmatte pro, so what you're seeing is direct output from FCP.

BTW, you probably don't want a color profile associated with your stills. HD is essentially sRGB, and so is your XP box, so even without a profile in PS, you should be seeing accurate colors. Profiles tend to confuse people anyway, so I only recommend you use them when you're dealing with images that have very wide or different colorspaces such as Adobe RGB.

If you have a PC, don't sweat the difference between Apple gamma (1.8) and PC gamma (2.2). FCP handles the gamma conversion behind the scenes. If you want to be extra faithful, you can apply the sRGB profile to frame grabs from FCP in PS, when you're on your Mac. That way PS will know to darken the frame up a bit for viewing. Again, not needed on a PC.

Make sense? Or just more confusing? :)

Ben - ah, I understand. So as long as the camera is stationary (probably a good assumption for non-star wars filming - the screen correction image can help to get a better mask.

As to color profiles, I'm used to working with RAW still images and doing the editing in Adobe RGB with a convertion to sRGB to output for the web.

I don't have Photoshop installed in the Mac, I suppose I will.

But, you seem to be saying that I can assign a profile of sRGB (on the PC) if I open a grab created from FCP on the Mac.

As for the gamma, if I open the sRGB labeled PS file on the PC, you seem to say that I don't have to worry about gamma?

I'm going to have to deal with similar issues (on gamma) when outputting Flash using Squeeze. I'll probably do that on the Mac as it Squeeze will eat ProRes 422 HQ on the Mac, but doesn't know what to do with it on the PC.

BTW - saw that Sorensen just added H.264 to Squeeze. Have to see if any advantages over Compressor.

Cheers!

Exactly.

Yup!

Nope!

The issue is: who do you target? Mac users or PC users? If PC users, you'll do nothing to the gamma. If Mac users, you'll want to decrease the gamma by 0.4. Unfortunately, neither platform is smart enough to understand the source colorspace and compensate accordingly. :P

Ben - it sounds like if my main market is web viewed on Windows, I should adjust the gamma of my Mac monitors to follow the Windows gamma? Does that sound reasonable?

Now if I can just figure a way to calibrate my hdmi output from FCP to 24" Samsung 245T (rather neat monitor, hdmi, dvi, rgb, s-video inputs).

I forgot to figure how I was going to calibrate the hdmi input, as my GretagMacbeth Eye One Display has no desktop or mouse on that monitor when receiving output from FCP thru hdmi.

Always something!

Les, FCP will adjust the gamma automatically to 2.2 while you're editing. What I'm unsure of in whether Compressor will apply that gamma when you output. I don't believe it does, but I could be wrong... In that case, you'll want to adjust the gamma when outputting using Compressor.

clothing for green screen
 

Hi Ben
Other than the obvious ( green ) what color and type of clothing should I tell the talent looks best for keying.Look forward to getting your new software as will doing much green screen in the near future.
Thanks, Aldo

will new dvMatte Pro work in Motion
 

Ben - will the new version of dvMatte Pro work in Motion? Thanks!