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How to capture video best for keying

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Drew JensenHow to capture video best for keying
by on Nov 6, 2009 at 8:40:43 pm

I was wondering if there is a better way to record video. Right now, I'm using the Canon XH A1 and I record straight from the camera via firewire and capture using Premiere Pro. I record using the HDV format. I know that keying can be a problem while using a type of DV format and was wondering if there is a better way to capture the video so that keying will be a little bit easier. I'm new to after effects and premiere, well, video editing in general. I have to export in flv and it seems the combination of these factors produces ok results but I'm sure they can be better. If any of you guys have tips on video capturing, please let me know.


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david bogieRe: How to capture video best for keying
by on Nov 6, 2009 at 10:24:26 pm

Keying relies on three things: Lighting the set properly, adequate chroma resolution, and adequate pixel resolution. DV blows because of the pixel quantizing. The best keys have those buzzing squares because that's what the pixels look like.
If you can't all three of those factors working in your favor, you learn how to cope. With DV, that often means suing several copies of your footage each processed with a different type of keyer, image enhancer, or matte filter. When you combine theam all together, you can get a lovely matte.

You can research chromakeying with DV endlessly o the Net and, if that's the only video format you've got at your disposal, you can get a DV-specific or DV-friendly keyer. One of them is called something like DV Garage.

bogiesan



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Kevin CampRe: How to capture video best for keying
by on Nov 6, 2009 at 10:32:14 pm

you could probably better specifics for capturing in premiere in the premiere forum, but in general, for keying in ae, hdv is about as bad as it gets codec-wise.

hdv has heavy compression of it's color components, which is really bad for keying. plus, it uses inter-frame compression, which is really bad for working in ae.

since you are capturing via firewire (i assume firewire400), the best codec you may be able to use is dvcprohd (also called dvcpro100), but i don't know how that works in premiere. i do know that starting with cs3, there is native support of panasonic's p2 media and that uses the dvcprohd codec, so you may be able to set premiere up with p2 settings to capture to dvcprohd.

the advantage of dvcprohd is that it will give you better color sampling (more color data to work with in keying) and it only uses intra-frame compression, which works much better in ae.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW


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Dave LaRondeRe: How to capture video best for keying
by on Nov 6, 2009 at 10:59:41 pm

What Bogie says is right. What Kevin says is right, too.

If you have no other choice but to chroma key in HDV, you'll pretty much have to resign yourself to crummy-looking edges on your keys, as Bogie says. Why? HDV has lousy color resolution. It's just as bad as DV's color resolution. So what's color resolution, anyways? Watch this podcast and learn what you're up against:

http://macbreak.libsyn.com/index.php?post_id=70596

And to elaborate on Kevin's "don't use the HDV codec" admonition, here's why:

Dave's Stock Answer #1:

If the footage you imported into AE is any kind of the following -- footage in an HDV acquisition codec, MPEG1, MPEG2, mp4, m2t, H.261 or H.264 -- you need to convert it to a different codec.

These kinds of footage use temporal, or interframe compression. They have keyframes at regular intervals, containing complete frame information. However, the frames in between do NOT have complete information. Interframe codecs toss out duplicated information.

In order to maintain peak rendering efficiency, AE needs complete information for each and every frame. But because these kinds of footage contain only partial information, AE freaks out, resulting in a wide variety of problems.


Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Drew JensenRe: How to capture video best for keying
by on Nov 9, 2009 at 7:11:32 pm

You talk about converting the format. I have a few more questions if you don't mind answering them. So, I'm using a Canon XH-A1 and we use firewire connection to record using premiere pro. Now, is there a different codec/format I can use in premiere pro to capture for better editing and chroma keying, or do I just need to convert it after being capture? If needing to convert, can you recommend a codec/format to use and program to use?


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Dave LaRondeRe: How to capture video best for keying
by on Nov 9, 2009 at 7:37:44 pm

[Drew Jensen] "...is there a different codec/format I can use in premiere pro to capture for better editing and chroma keying, or do I just need to convert it after being capture?"

As soon as the image is recorded to the camera, the color resolution damage is done, and there's no going back to improve it. It's just that HDV gives AE fits.

If you want to preserve color resolution, you need to record the HDMI output of your camera as you capture in an editing application using a capture card... and I don't know what to use with Premiere and a Windows box; I'm a Mac guy. If your camera doesn't have such a high-quality video output, you're stuck.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Drew JensenRe: How to capture video best for keying
by on Nov 9, 2009 at 7:41:15 pm

I really wish I could have gotten a Mac but I didn't have that much pull here at work when they were deciding on a computer for editing. We don't really didn't do editing for this so we really didn't know what kind of setup to get but now we are starting to regret the stuff we got as I learn more and more. Anyways, could you possibly recommend a camera under 5,000 or so that can capture using a good codec for AE?


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Dave LaRondeRe: How to capture video best for keying
by on Nov 9, 2009 at 9:52:02 pm

[Drew Jensen] "...could you possibly recommend a camera under 5,000 or so that can capture using a good codec for AE?"

Look at the Panasonic HVX 200 or some other Panasonic P2 camera. But before you take the plunge, make darned sure you know the drill for transferring P2 footage to your NLE.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Todd KoprivaRe: How to capture video best for keying
by on Nov 7, 2009 at 2:25:27 am

The "Keying introduction and resources" page includes links to several good resources about acquiring footage for keying. There's also a link to the KeyerforDV animation preset, which helps a bit with keying DV footage.

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Todd Kopriva, Adobe Systems Incorporated
putting the 'T' back in 'RTFM' : After Effects Help on the Web
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If a page of After Effects Help answers your question, please consider rating it. If you have a tip, technique, or link to share---or if there is something that you'd like to see added or improved---please leave a comment.


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Steve RobertsRe: How to capture video best for keying
by on Nov 7, 2009 at 9:39:04 am

It's a shame for a good Irishman to admit it, but I'm not up on my new cameras ...
(sorry, lame reference)

... but do you have access to a camera that can record to hard drive through the HDMI port? If so, you might get better results. This is way out of my depth (!) though, so unless one of the wise folks here can offer something, you might want to check a videography forum.




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