File: Readme_AddGrain.txt

//  AddGrain - Random noise film grain generator for Avisynth 2.5
//	Copyright (C) 2003 Tom Barry  - trbarry@trbarry.com
//
//	This program is free software; you can redistribute it and/or modify
//	it under the terms of the GNU General Public License as published by
//	the Free Software Foundation; either version 2 of the License, or
//	(at your option) any later version.
//
//	This program is distributed in the hope that it will be useful,
//	but WITHOUT ANY WARRANTY; without even the implied warranty of
//	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//	GNU General Public License for more details.
//
//	You should have received a copy of the GNU General Public License
//	along with this program; if not, write to the Free Software
//	Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

Also, this program is "Philanthropy-Ware".  That is, if you like it and feel
the need to reward or inspire the author then please feel free (but not obligated) 
to consider joining or donating to the Electronic Frontier Foundation. This will 
help keep cyber space free of barbed wire and bullsh*t.  

See their web page at www.eff.org

***************

Okay, on to business. 

WARNING - This version only runs on the Avisynth 2.5+ release.

AddGrain generates film like grain or other effects (like rain) by adding
random noise to a video clip.  This noise may optionally be horizontally 
or vertically correlated to cause streaking.

USAGE - To use it just:

1) Place the AddGrain.dll in a directory somewhere. If that is the C:\Program
Files\AviSynth 2.5\plugins folder folder (recommended) then you can omit the
LoadPlugin command in your script. You can get AddGrain from:

   www.trbarry.com

2) In your Avisynth file use commands similar to 

    LoadPlugin("F:\AddGrain\AddGrain.dll")
    Avisource("D:\wherever\myfile.avi")
    AddGrain(20,0,0)
	
Of course replace the file and directory names with your own.  

PARAMETERS

AddGrain(float stddev, float HorizCorr, float VerticalCorr)

where:

	stddev = the standard deviation of the noise generated.
	
	HorizCorr = the horizontal correlation factor, causing horizontal
		steaking.  (0.0 to 1.0)
		
	VerticalCorr = the vertical correlation factor. (0.0 to 1.0)
	

The correlation factors are actually just implemented as exponential smoothing
which give a weird side affect that I did not attempt to adjust.  But this means
that as you increase either corr factor you will have to also increase the stddev
(grain amount) in order to get the same visible amount of grain, since it is being 
smooth out a bit.

Increase both corr factors can somewhat give clumps, or larger grain size. 

And there is an interesting effect with, say, AddGrain(800,0,.9) or any huge amount 
of strongly vertical grain.  It can make any scene look like it is raining.


KNOWN ISSUES AND LIMITATIONS

1) 	Requires Avisynth 2.5 and YV12 input.        


FILE LOCATIONS

For now, both source, this readme, and DLL should be at:
	
	www.trbarry.com

***************

Change Log:

2003/06/181  V 0.1.0.0  Initial test release for Avisynth 2.5 only





























