The full (paid) version of GoPro-Cineform Neo (as I have) does support alpha channels.
(A colleague initially thought otherwise – but that impression turned out to be based on info from old forum threads)
Archive for the ‘chroma’ Category
Cineform and Alpha Channels
Friday, August 31st, 2012Chroma Upsampling (Chroma Interpolation)
Friday, August 31st, 2012Shooting green-screen onto a 4:2:0 chroma-subsampled format, intending of course to use it for chroma-keying. Obvious disadvantage is green-ness of green-screen only gets sampled at quarter-resolution. Not a show-stopper, given my target deliverable is standard definition, but anyhow, towards perfectionism, is there any way to up-sample to 4:4:4 i.e. full definition colour?
It does occur to me that something more sophisticated than chroma blur ought to be possible, broadly along the lines of edge-following methods employed in resizing. What’s out there?
- Simplest method, that most people seem to use, is chroma-blur. That’s only the chroma, not the luma.
- Searching around, Graham Nattress has analysed the problem and seems to have produced a more mathematical approach. But it’s only available (at time of writing) for Final Cut (which of course is Mac-only at present).
Some tools that “promise” upsampling, but I wonder by what methods:
- GoPro-CineForm intermediate. The codec settings include an option to up-sample to 4:4:4
- Adobe Premiere, but only if a Color Corrector effect employed.
- But the crucial thing here, regarding the usefulness of this, is whether it uses any better method than chroma blur.
Some questions:
- Does Adobe have anything built-in to do something Nattress-like nowadays?
- DaVinci Resolve?
- Boris?