A1 Subsampling HDV Color Scheme?

[GL2guy]

Anyone know the A1's HDV subsampling color scheme? Is it 4:2:0?

And how much better would the XH A1 be at chroma keying in HDV as opposed to chroma keying with the GL2's SD DV footage?? Thanks.

[manglerBMX]

i've done some chroma keying with the h1 and its simply amazing.

[GL2guy]

i've done some chroma keying with the h1 and its simply amazing.

In HDV or uncompressed HD?

[Jason Ramsey]

All HDV, that I know of is 4:2:0

Jason

[GL2guy]

All HDV, that I know of is 4:2:0

Jason

Yea... is that good for chroma keying? As opposed to whatever the color subsampling is for standard DV? I just want to get a general idea how easy chromakeying will be with HDV footage as opposed to standard DV footage. Thanks.

[Jason Ramsey]

Well, I can't tell you from experience, but in comparison to "regular" dv... for NTSC land it is 4:1:1, and for PAL it is 4:2:0. So a pal mini dv and hdv have the same.
4:1:1 = 4 pixels horizontally equals different shades of one color.
4:2:0 = 2 pixels on line one, 2 pixels directly below it on line 2. Those 4 pixels are different shades of one color.
4:2:2 = (which is dvcpro 50, dvcpro hd) 2 pixels horizontally for one color.
And of course there is 4:4:4, which is one pixel per color

Not the best explanation of color space, but pretty much that's it.
So, in theory 4:1:1 would be the worst for chromakey and 4:4:4 would obviously be the best.

But, I am sure that with a good program and a skilled person manning it, one could get good results from any of those. It will just require more work, and be more difficult to get a clean key from 4:2:0 compared to 4:2:2, for example.

Again, I can't tell you from personal experience. I am sure someone can chime in on that though.

Jason

[Elton]

I've had good results, but it does take a bit of finesse. Most of the time I simply transcode HDV to a better codec like Sheer or uncompressed to pull the key. It helps to preserve quality and render cleaner edges.