HV20 working out well for greenscreen!

Les Caudle · November 24th, 2007, 09:46 AM

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!

Joseph H. Moore · November 24th, 2007, 10:11 AM

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.)

Les Caudle · November 24th, 2007, 12:22 PM

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!

Joseph H. Moore · November 24th, 2007, 12:30 PM

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.

Les Caudle · November 24th, 2007, 01:14 PM

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

Joseph H. Moore · November 24th, 2007, 01:32 PM

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.

Ben Syverson · November 24th, 2007, 06:11 PM

Quote:

Originally Posted by Joseph H. Moore

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.

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

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

Joseph H. Moore · November 24th, 2007, 06:41 PM

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.)

Ben Syverson · November 24th, 2007, 08:24 PM

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

Les Caudle · November 25th, 2007, 11:43 AM

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!

Ben Syverson · November 25th, 2007, 02:58 PM

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. :)

Les Caudle · November 26th, 2007, 10:04 AM

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!

Ben Syverson · November 26th, 2007, 02:15 PM

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!

Anton Galimzyanov · November 26th, 2007, 06:15 PM

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 -))

Ben Syverson · November 26th, 2007, 08:56 PM

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

November 24th, 2007, 09:46 AM	#46
Les Caudle Regular Crew Join Date: Nov 2007 Location: Los Angeles, CA Posts: 45	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!

November 24th, 2007, 10:11 AM	#47
Joseph H. Moore Major Player Join Date: Oct 2005 Posts: 362	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.)

November 24th, 2007, 12:22 PM	#48
Les Caudle Regular Crew Join Date: Nov 2007 Location: Los Angeles, CA Posts: 45	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!

November 24th, 2007, 12:30 PM	#49
Joseph H. Moore Major Player Join Date: Oct 2005 Posts: 362	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.

November 24th, 2007, 01:14 PM	#50
Les Caudle Regular Crew Join Date: Nov 2007 Location: Los Angeles, CA Posts: 45	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

November 24th, 2007, 01:32 PM	#51
Joseph H. Moore Major Player Join Date: Oct 2005 Posts: 362	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.

November 24th, 2007, 06:41 PM	#53
Joseph H. Moore Major Player Join Date: Oct 2005 Posts: 362	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.)

November 24th, 2007, 08:24 PM	#54
Ben Syverson Major Player Join Date: Mar 2004 Location: chicago Posts: 434	Oh, yes. I'm sure the HDMI looks amazing!

November 25th, 2007, 11:43 AM	#55
Les Caudle Regular Crew Join Date: Nov 2007 Location: Los Angeles, CA Posts: 45	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!

November 25th, 2007, 02:58 PM	#56
Ben Syverson Major Player Join Date: Mar 2004 Location: chicago Posts: 434	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. :)

November 26th, 2007, 10:04 AM	#57
Les Caudle Regular Crew Join Date: Nov 2007 Location: Los Angeles, CA Posts: 45	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!

November 26th, 2007, 02:15 PM	#58
Ben Syverson Major Player Join Date: Mar 2004 Location: chicago Posts: 434	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!

November 26th, 2007, 06:15 PM	#59
Anton Galimzyanov Regular Crew Join Date: Feb 2005 Location: Moscow, Russia Posts: 53	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 -))

November 26th, 2007, 08:56 PM	#60
Ben Syverson Major Player Join Date: Mar 2004 Location: chicago Posts: 434	How do you use it for exterior shots? Lug the whole computer outside?