Regrain Filter?

[Lyris]

Before I try and write one myself (this would be my first function), is there an AVIsynth filter which will Regrain an image?

I'm aware of tools like AddNoise and the more elaborate GrainFactory, which are great - but what I want to do is snap a featureless area of grain from another movie and replicate it as best as I can on another clip (a la Adobe After Effects). Does anyone know if such a filter exists already?

[leeperry]

"snap a featureless area of grain from another movie and replicate it as best as I can on another clip" ? sounds great, eager to try it :)

did you play around w/ GrainF3? you can get stunning results w/ this script!

[Lyris]

I did indeed. My biggest issue with GrainFactory 3 so far has been that the grain is always perfect 1:1 resolution. I had a source needing grained which featured grain crystals/pixels that were taller than they were wider. So I altered the script to scale the grain. This was a very close match, but I would still like to experiment with regraining from a genuine grain snapshot.

I suppose such a script would have to,

1. Use ImageReader to read the grain snapshot,
2. Offset it by a random position for each frame,
3. Fine some way of feathering the edges to allow it to be "tiled" over the video,
4. Tile it,
5. and then overlay, probably using the same methods as GrainFactory3.

I wonder if this (particularly #2) is possible with AVISynth?

[leeperry]

"1:1 resolution"? you mean you'd like to have big asymetrical chunks of silver grain all over the screen?

maybe Didée would have an idea or two about that to shoot for GrainFactory_Reloaded() or something :D

[Lyris]

Not BIG chunks, no - but not pixel-perfect ones, either. It'd look more realistic for some sources, and also compress better.