HV20 working out well for greenscreen!

Lawrence Bansbach · November 15th, 2007, 08:57 AM

What bit depths will the new version of dvMatte Pro support -- full 32-bit floating point? What resolutions? And will there be a Windows version at some point?

Ben Syverson · November 15th, 2007, 01:25 PM

Lawrence,

The plugin will run at 32bit floating point, but there is no benefit to doing so. Internally, the plugin operates at 32 or 16 bit floating point, depending on the graphics card present. So even working with 8 bit footage, you get the precision of floating point.

The resolution is limited by what the graphics card can handle. Most cards are 2k at this point, but some new cards have 4k support.

Joseph H. Moore · November 15th, 2007, 07:19 PM

It's sounds like the newly announced FCE 4 supports the same plug-in architecture.

Ben,
Do you think it's likely that the new dvmatte will function in the new Express?

Ben Syverson · November 16th, 2007, 01:23 PM

Joseph,

I haven't done any testing with it, but FCE does support FxPlug, which means dvmatte will probably run great!

Kent Golden · November 23rd, 2007, 01:18 PM

Hi Ben,
I do a lot of chroma keying and just purchased an HV20. Your dvmatte sample looks great!

Can you please tell me if you recommend using the 24p mode or the normal interlaced mode for chroma keying with the HV20?

If you recommend 24p, can you also please let me know which process you use for encoding the video with the HV20 (i.e. do you get true 24p with the reverse telecine)? Are you using Apple's method (in link below)?

http://docs.info.apple.com/article.html?artnum=306389

I have an important project coming up, and I want to be sure everything will work properly.

Thanks!

- Kent

Ben Syverson · November 23rd, 2007, 01:55 PM

Hi Kent,

Cool! You won't be disappointed. The choice of 24p or 30i will really depend on the rest of your project, since you presumably want the greenscreen stuff to fit in with your other footage...

That said, progressive footage may have the edge, because interlacing really stresses the MPEG codec used in HDV. Also, 24p is more sensitive to light, so the camera won't kick on the gain as quickly.

I do use that Apple technique to convert the footage to true 24p. It works great!

Kent Golden · November 23rd, 2007, 02:24 PM

Hi Ben,
Thanks for the info. I am actually using the chroma footage in a Flash program, so progressive seems best.

Thanks again!

- Kent

Les Caudle · November 23rd, 2007, 08:14 PM

Ben - I purchased an Intensity card to use with Final Cut Studio 2 and the HV20 for green screens.

1. When I capture at 1920 x 1080 60i 'live' from the HDMI (to ProRes 422 HQ), exactly what am I getting? I get very different feedback depending on who I ask.

Is it 60 fields, each recorded at 60 distinct intervals per second (no field matches the time of any other)?

Or, is it 60 fields, with 2 field recorded at the exact same time, the frame broken up into even and odd fields so that it can be packaged in 60i?

2. If I capture 24p HDV, encapsulated in 60i, what am I getting? Are there 48 fields (odd and even) captured at exactly the same instant, but packaged into a 60i stream with the pulldown frames added?

In other words. Is it progressive for HDMI capture? Is it progressive for HDV 24p capture? But, all packaged within 60i?

3. Are there any settings on the HV20 that will affect the output when capturing thru HDMI? I'm really hoping that with the better color space - and no MPEG compression, I can get better output.

4. Any word yet on when your new version of dvMatte Pro will be out?

BTW - it would be nice to have a 'versions' page on the dvgarage.com site. I have no idea what version is currently shipping, the bugs fixed in previous versions, etc.

Joseph H. Moore · November 23rd, 2007, 08:52 PM

1. When capturing 60i, each field is a unique moment in time, each field is different. This is easy to see when you step through your deinterlaced footage.

2. When capturing 24P, each combination of fields is a discrete moment. The sensor is truly progressive.

3. Whether recording to HDV or going out the HDMI port, the 24P is encoded into a 60i stream.

4. Most, if not all, of the HV20's image settings affect the HDMI output. If you think about the image chain, the HDMI output sits immediately before the HDV compression.

5. You're gonna want to keep all of the image settings at 0 or -1. Especially SHARPNESS if you're keying.

Les Caudle · November 23rd, 2007, 09:19 PM

Joseph - why in the world would they use a progressive sensor and muck it up by taking 60 distinct fields? They could have packaged this as 30p in 60i, couldn't they?

You seem to be saying that 24p is possible out of the HDMI?

Is there a way to get 24p, or any true progressive stream - out of the HDMI with a 'live' capture? Or, am I stuck with 60 discreet odd/even moments in time that won't exactly ever fit together properly?

BTW - if you happen to be a FCP user, any tips on the best way to de-interlace the 60i HDMI, if what I'm stuck with are truly 60 distinct moments in time, how can you de-interlace something where the parts are not meant to fit together?

Ben Syverson · November 23rd, 2007, 11:18 PM

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)...

Ben Syverson · November 23rd, 2007, 11:22 PM

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.

Joseph H. Moore · November 23rd, 2007, 11:30 PM

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.)

Les Caudle · November 24th, 2007, 09:30 AM

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!

Joseph H. Moore · November 24th, 2007, 09:37 AM

Quote:

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?

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

Quote:

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?

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.

November 23rd, 2007, 01:18 PM	#35
Kent Golden Tourist Join Date: Nov 2007 Location: New Haven, CT Posts: 2	24p process question Hi Ben, I do a lot of chroma keying and just purchased an HV20. Your dvmatte sample looks great! Can you please tell me if you recommend using the 24p mode or the normal interlaced mode for chroma keying with the HV20? If you recommend 24p, can you also please let me know which process you use for encoding the video with the HV20 (i.e. do you get true 24p with the reverse telecine)? Are you using Apple's method (in link below)? http://docs.info.apple.com/article.html?artnum=306389 I have an important project coming up, and I want to be sure everything will work properly. Thanks! - Kent Last edited by Kent Golden; November 23rd, 2007 at 01:19 PM. Reason: added email notification

November 15th, 2007, 08:57 AM	#31
Lawrence Bansbach Major Player Join Date: Dec 2004 Posts: 295	What bit depths will the new version of dvMatte Pro support -- full 32-bit floating point? What resolutions? And will there be a Windows version at some point?

November 15th, 2007, 01:25 PM	#32
Ben Syverson Major Player Join Date: Mar 2004 Location: chicago Posts: 434	Lawrence, The plugin will run at 32bit floating point, but there is no benefit to doing so. Internally, the plugin operates at 32 or 16 bit floating point, depending on the graphics card present. So even working with 8 bit footage, you get the precision of floating point. The resolution is limited by what the graphics card can handle. Most cards are 2k at this point, but some new cards have 4k support.

November 15th, 2007, 07:19 PM	#33
Joseph H. Moore Major Player Join Date: Oct 2005 Posts: 362	It's sounds like the newly announced FCE 4 supports the same plug-in architecture. Ben, Do you think it's likely that the new dvmatte will function in the new Express?

November 16th, 2007, 01:23 PM	#34
Ben Syverson Major Player Join Date: Mar 2004 Location: chicago Posts: 434	Joseph, I haven't done any testing with it, but FCE does support FxPlug, which means dvmatte will probably run great!

November 23rd, 2007, 01:55 PM	#36
Ben Syverson Major Player Join Date: Mar 2004 Location: chicago Posts: 434	Hi Kent, Cool! You won't be disappointed. The choice of 24p or 30i will really depend on the rest of your project, since you presumably want the greenscreen stuff to fit in with your other footage... That said, progressive footage may have the edge, because interlacing really stresses the MPEG codec used in HDV. Also, 24p is more sensitive to light, so the camera won't kick on the gain as quickly. I do use that Apple technique to convert the footage to true 24p. It works great!

November 23rd, 2007, 02:24 PM	#37
Kent Golden Tourist Join Date: Nov 2007 Location: New Haven, CT Posts: 2	Hi Ben, Thanks for the info. I am actually using the chroma footage in a Flash program, so progressive seems best. Thanks again! - Kent

November 23rd, 2007, 08:14 PM	#38
Les Caudle Regular Crew Join Date: Nov 2007 Location: Los Angeles, CA Posts: 45	Ben - I purchased an Intensity card to use with Final Cut Studio 2 and the HV20 for green screens. 1. When I capture at 1920 x 1080 60i 'live' from the HDMI (to ProRes 422 HQ), exactly what am I getting? I get very different feedback depending on who I ask. Is it 60 fields, each recorded at 60 distinct intervals per second (no field matches the time of any other)? Or, is it 60 fields, with 2 field recorded at the exact same time, the frame broken up into even and odd fields so that it can be packaged in 60i? 2. If I capture 24p HDV, encapsulated in 60i, what am I getting? Are there 48 fields (odd and even) captured at exactly the same instant, but packaged into a 60i stream with the pulldown frames added? In other words. Is it progressive for HDMI capture? Is it progressive for HDV 24p capture? But, all packaged within 60i? 3. Are there any settings on the HV20 that will affect the output when capturing thru HDMI? I'm really hoping that with the better color space - and no MPEG compression, I can get better output. 4. Any word yet on when your new version of dvMatte Pro will be out? BTW - it would be nice to have a 'versions' page on the dvgarage.com site. I have no idea what version is currently shipping, the bugs fixed in previous versions, etc.

November 23rd, 2007, 08:52 PM	#39
Joseph H. Moore Major Player Join Date: Oct 2005 Posts: 362	1. When capturing 60i, each field is a unique moment in time, each field is different. This is easy to see when you step through your deinterlaced footage. 2. When capturing 24P, each combination of fields is a discrete moment. The sensor is truly progressive. 3. Whether recording to HDV or going out the HDMI port, the 24P is encoded into a 60i stream. 4. Most, if not all, of the HV20's image settings affect the HDMI output. If you think about the image chain, the HDMI output sits immediately before the HDV compression. 5. You're gonna want to keep all of the image settings at 0 or -1. Especially SHARPNESS if you're keying.

November 23rd, 2007, 09:19 PM	#40
Les Caudle Regular Crew Join Date: Nov 2007 Location: Los Angeles, CA Posts: 45	Joseph - why in the world would they use a progressive sensor and muck it up by taking 60 distinct fields? They could have packaged this as 30p in 60i, couldn't they? You seem to be saying that 24p is possible out of the HDMI? Is there a way to get 24p, or any true progressive stream - out of the HDMI with a 'live' capture? Or, am I stuck with 60 discreet odd/even moments in time that won't exactly ever fit together properly? BTW - if you happen to be a FCP user, any tips on the best way to de-interlace the 60i HDMI, if what I'm stuck with are truly 60 distinct moments in time, how can you de-interlace something where the parts are not meant to fit together?

November 23rd, 2007, 11:18 PM	#41
Ben Syverson Major Player Join Date: Mar 2004 Location: chicago Posts: 434	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)...

November 23rd, 2007, 11:22 PM	#42
Ben Syverson Major Player Join Date: Mar 2004 Location: chicago Posts: 434	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.

November 23rd, 2007, 11:30 PM	#43
Joseph H. Moore Major Player Join Date: Oct 2005 Posts: 362	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.)

November 24th, 2007, 09:30 AM	#44
Les Caudle Regular Crew Join Date: Nov 2007 Location: Los Angeles, CA Posts: 45	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!