Consumer cameras for green screen

Seth Bloombaum · March 24th, 2011, 06:33 PM

AFAIK, Cineform doesn't support a transparency channel, so, is unsuitable for output from CineGobs unless you are doing your composite in CG.

Lagarith supposedly supports a transparency channel, but I've never seen it work with Vegas. I mean, Lagarith DOES work with Vegas, but, the transparency channel is somehow not implemented in a way that V can read/write it. This is probably worthy of further investigation.

That leaves uncompressed as the only AVI format that one can export from CG with transparency. Maybe there's a png export from CG?

I just opened CG, and I see that Lagarith transparency is supported, as well as Full Frames (uncompressed). These would be the two most straightforward methods for output with a transparency channel.

I also see options for "output type = AVI (rgb file + alpha file)". That might work really well with Cineform. In ancient times we frequently worked with a separate matte channel with hardware keyers and switchers, you would take both these files to the Vegas timeline and set up, um, a compositing child track? I haven't actually done that in Vegas.

Jim Andrada · March 24th, 2011, 08:32 PM

If by Transparency Channel" you're referring to "Alpha Channel", Cineform does support it but think only in something like NEO 2K/4K and not in the lower priced versions.

A good question for the Cineform forum.

Which in a way is a problem with the forum structure - if you have a straight Vegas question the the Vegas forum is the place to go but if you have a question about Cineform and Vegas it isn't immediately clear whether to go to the Vegas forum or to the Cineform forum.

Steve Kalle · March 25th, 2011, 10:17 PM

From my experience, the cleaner the image, the easier and better the keying will be. I find the H264 from DSLRs has quite a bit of compression artifacts while the EX1/3 have quite a bit of noise, and using an external recorder does not 'greatly' enhance keying, but it does help a little. I compared a 280Mb I-frame from a nanoFlash and the internal 35Mb 420 from an EX3 by using Keylight with identical settings, and I couldn't see any difference in the key quality. I used a Rycote Softie as the subject with Kino's and a Matthews GS.

About the BM Shuttle: what would he record to because a single drive cannot handle uncompressed 1080 30p 422 at ~125MB/s.

If there is a lot of motion being recorded, a 1080 60p camera would help due to motion blur reeking havoc on keys.

Oren Arieli · March 26th, 2011, 12:50 AM

He wouldn't be recording uncompressed. The work he does is web-video introductions. Full body shots with mcu inserts. The main point is to save time in acquisition/transfer/post, thus maximize his income potential and turnaround time. Currently, the leading choice seems to be a Core i7 laptop with USB 3 for the BM Shuttle and external drive. This would allow for quickest ingest (via HDMI), no transcode (CS5) and fastest turnaround. So I guess the next question is...which gaming laptop to choose.

Seth Bloombaum · March 26th, 2011, 10:37 AM

Quote:

Originally Posted by Oren Arieli

He wouldn't be recording uncompressed. The work he does is web-video...

BM doesn't give you very many codec choices at all. In their capture software for the Intensity Pro, you get uncompressed and their own MJPEG, that's it. Some other capture programs can see the BMI, but, exactly what method would he use to not record uncompressed?

Quote:

Originally Posted by Steve Kalle

...About the BM Shuttle: what would he record to because a single drive cannot handle uncompressed 1080 30p 422 at ~125MB/s...

Steve is quite right - in my experience as well, the minimum disk requirement for working with BM Intensity is a 2-disk hardware-controlled RAID 0, minimum of good SATA 2.

Quote:

Originally Posted by Oren Arieli

...the leading choice seems to be a Core i7 laptop with USB 3 for the BM Shuttle and external drive. This would allow for quickest ingest (via HDMI), no transcode (CS5) and fastest turnaround. So I guess the next question is...which gaming laptop to choose.

I don't have any experience with USB3 yet, but my concerns would be:
Can the data transport protocol Intensity Shuttle uses run concurrently on the same USB3 bus as external drives?
What is the minimum USB3 external drive configuration to capture at the desired resolution & format?

My basic question is whether BM support or users on forums are sharing experience about the config Oren's friend is considering, because otherwise it is an expensive experiment!

March 24th, 2011, 06:33 PM	#16
Seth Bloombaum Inner Circle Join Date: Sep 2003 Location: Portland, Oregon Posts: 3,420	Re: Consumer cameras for green screen AFAIK, Cineform doesn't support a transparency channel, so, is unsuitable for output from CineGobs unless you are doing your composite in CG. Lagarith supposedly supports a transparency channel, but I've never seen it work with Vegas. I mean, Lagarith DOES work with Vegas, but, the transparency channel is somehow not implemented in a way that V can read/write it. This is probably worthy of further investigation. That leaves uncompressed as the only AVI format that one can export from CG with transparency. Maybe there's a png export from CG? I just opened CG, and I see that Lagarith transparency is supported, as well as Full Frames (uncompressed). These would be the two most straightforward methods for output with a transparency channel. I also see options for "output type = AVI (rgb file + alpha file)". That might work really well with Cineform. In ancient times we frequently worked with a separate matte channel with hardware keyers and switchers, you would take both these files to the Vegas timeline and set up, um, a compositing child track? I haven't actually done that in Vegas. __________________ 30 years of pro media production. Vegas user since 1.0. Webcaster since 1997. Freelancer since 2000. College instructor since 2001.

March 24th, 2011, 08:32 PM	#17
Jim Andrada Inner Circle Join Date: Feb 2007 Location: Tucson AZ Posts: 2,211	Re: Consumer cameras for green screen If by Transparency Channel" you're referring to "Alpha Channel", Cineform does support it but think only in something like NEO 2K/4K and not in the lower priced versions. A good question for the Cineform forum. Which in a way is a problem with the forum structure - if you have a straight Vegas question the the Vegas forum is the place to go but if you have a question about Cineform and Vegas it isn't immediately clear whether to go to the Vegas forum or to the Cineform forum.

March 25th, 2011, 10:17 PM	#18
Steve Kalle Trustee Join Date: Aug 2009 Location: Chicago, IL Posts: 1,554	Re: Consumer cameras for green screen From my experience, the cleaner the image, the easier and better the keying will be. I find the H264 from DSLRs has quite a bit of compression artifacts while the EX1/3 have quite a bit of noise, and using an external recorder does not 'greatly' enhance keying, but it does help a little. I compared a 280Mb I-frame from a nanoFlash and the internal 35Mb 420 from an EX3 by using Keylight with identical settings, and I couldn't see any difference in the key quality. I used a Rycote Softie as the subject with Kino's and a Matthews GS. About the BM Shuttle: what would he record to because a single drive cannot handle uncompressed 1080 30p 422 at ~125MB/s. If there is a lot of motion being recorded, a 1080 60p camera would help due to motion blur reeking havoc on keys.

March 26th, 2011, 12:50 AM	#19
Oren Arieli Major Player Join Date: May 2007 Location: San Jose, California Posts: 919	Re: Consumer cameras for green screen He wouldn't be recording uncompressed. The work he does is web-video introductions. Full body shots with mcu inserts. The main point is to save time in acquisition/transfer/post, thus maximize his income potential and turnaround time. Currently, the leading choice seems to be a Core i7 laptop with USB 3 for the BM Shuttle and external drive. This would allow for quickest ingest (via HDMI), no transcode (CS5) and fastest turnaround. So I guess the next question is...which gaming laptop to choose.