View Full Version : question about keying

10 October 2003, 06:52 PM
Just a doubt,

Is there difference among keying a DV, HD or 2K shot (using green-screen)?


10 October 2003, 08:31 PM
Heaps of difference! not so much in the spacial resolution, but in the colour compression. DV in particular is very hard to key, as the chroma channels are effectivly quarter size or so (depending on whether its NTSC or PAL the chroma sampling changes, but the fact is, its a bitch to key)

the best results of keying DV footage are found by blurring the chroma channels by 2-4 pixels prior to keying it (this can be done by blurring the footage with a blur operator, then assign a 'compound HSV arithmetic' operator - you set the V operator to Set, the V Layer to the same layer directly before the blur, the V input to Value, & the blend to 100%) That will give you far better DV keys.

I've never keyed off HD, & dont know what the compression is like, keying of 2k frames from 35mm is sweet - with the only problem you may encounter being grain (depending on the stock) Combustions grain removal tools will fix this though

10 October 2003, 01:41 PM
Hi Chris,

Thanx :beer:

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