greenscreen and hdv

ilauzirika

ilauzirika

Boring Senior Member
hi

I have a greenscreen gig in about two week time and I'm trying to find the best way to capture from a hdv (canon hv20) camera.

Is there anyway to capture from the computer with more quality than from tapes?

Thanks
 
well as far as I know, if you convert HDVs 4:2:0 to SD via a uncomrpessed SD codect you end up with full colour sampling i.e. 4:4:4 BUT at SD.

If your final output is SD, I would suggest that you donvert to MJPEG or HuffYUV or something like some umpressed file format to get full colour ,

or use the nattress filter:

http://www.nattress.com/ (g nicer?)

you could always use blackmagic I think to capture uncompressed HD from your cam, but its kind of pointless because its already sampled at 4:2:0.

my minds a fuzz please ignore my technical mistakes, tons more stuff on dvinfo and right here too about keying in HDV.
 
I don't know the specifics about aspectHD, I think in theory you may abe able to use blackmagic to capture the HD stream and use aspectHD to encode it on the fly, not sure about this.

But anyways, what is your final target desintation ?

SD or HD, that is the most important question, if its SD I personally would use HDV tapes, adn then convert to 4:4:4 SD format and then work on that.

If its for HD then you may want to consider a more expensive camera, eg HVX200, becasue then you will be working with HD @ 4:2:2 i think, not that keying in HDV @ HD is impossible
 
I will output it to sd. so I think i'll stick to the dv tapes and then downrez it by using a
uncompressed codec.

Thanks for the eye opening answers.
 
Anhar Miah said:
well as far as I know, if you convert HDVs 4:2:0 to SD via a uncomrpessed SD codect you end up with full colour sampling i.e. 4:4:4 BUT at SD.
Click to expand...

I don't think you can take it that far.. but HDV at 4:2:0 has more than twice the color information as SD at 4:1:1..

The Canopus HQ codec apparently will give you a 4:2:2 color space SD image, but I'd be surprised if you could get a legitimate 4:4:4 image from it.

But for the record, a good key can be pulled from HDV footage with minimal effort (assuming the screen is properly lit and the subject is well enough separated from it).
 
so which would be the best procedure?

Capture to tape- lay in a hd timeline- and render to sd (I would thank you if you could help me wiht this step) - then import in sd project in after effectss for further compositing.

The only problem I have is with the downscaling do I have to lay the 1440x1080 footage in a sd timeline or just lay it in a hdv timeline and the render it to sd?

Do anyone know of any website from where i candownload raw greenscreen footage for trying this procedure?

Sorry if I'm being too annoying and thanks for the help
 
I don't buy it.. just setting the color space to 4:4:4 isn't going to necessarily make use of that full range. I'm sure there is somewhere between the information of a 4:2:2 and a 4:4:4 space, but I would be very surprised if there was truly enough there to actually use the full 4:4:4 space.
 
tcindie said:
I don't buy it.. just setting the color space to 4:4:4 isn't going to necessarily make use of that full range. I'm sure there is somewhere between the information of a 4:2:2 and a 4:4:4 space, but I would be very surprised if there was truly enough there to actually use the full 4:4:4 space.
Click to expand...

well, that would be enough to get a better chroma key than just using 4:2:0 footage
or footage from a sd camera.

What i was trying to know is that if compromising the resolution and downscaling to 4:2:2 - 4:4:4 would be better than just key it from the hdv source.

All this being said, I think that I will just record it to hdv and try different ways to key , because as someone said practice is the key. (I'll try to post some comparison when I finish the project)

Thanks for all the help.
 
Technically speaking, there is no such thing as an "easy key", so you can always expect a certain amount of work additional to just applying the chroma key plugin/tool.. but that said, I was able to pull pretty good keys without additional work from HDV footage in its full resolution.

Practice is important, but no matter how much you practice you're likely to run across some footage at some point that is just a major pain to key, regardless of the resolution or color depth. I find it usually has more to do with how the shot was initially lit than it does with the format of video you're working with.

Properly lit chroma shots (evenly lit screen, separation of talent/etc from the screen, and no excessive color spill) can be pretty easy to key on virtually any format.
 
tcindie said:
Technically speaking, there is no such thing as an "easy key", so you can always expect a certain amount of work additional to just applying the chroma key plugin/tool.. but that said, I was able to pull pretty good keys without additional work from HDV footage in its full resolution.

Practice is important, but no matter how much you practice you're likely to run across some footage at some point that is just a major pain to key, regardless of the resolution or color depth. I find it usually has more to do with how the shot was initially lit than it does with the format of video you're working with.

Properly lit chroma shots (evenly lit screen, separation of talent/etc from the screen, and no excessive color spill) can be pretty easy to key on virtually any format.
Click to expand...

True. Once I did a greenscreen project just wiht a cheapo handycam and I got pretty good results (in my opinion and for being the first time), but it really was painful and in some shots I had to rotoscope everything. As I can see every greenscreen has its trick (lights ...).
 
ilauzirika said:
True. Once I did a greenscreen project just wiht a cheapo handycam and I got pretty good results (in my opinion and for being the first time), but it really was painful and in some shots I had to rotoscope everything. As I can see every greenscreen has its trick (lights ...).
Click to expand...

Yup.. and generally a certain amount of roto is required -- whether that's just a garbage mask to minimize the area that needs to be keyed, or actually rotoing every frame to use footage that can't otherwise is next to impossible to pull a key from. ;)
 
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